El presente trabajo tiene como finalidad la sustentación de un modelo de negocio que tiene como giro principal la producción y venta de hamburguesas de pota empanizadas con quinua y kiwicha, un producto dirigido para personas que llevan un estilo de vida saludable según Arellano Marketing, pertenecientes a las zonas 6 y 7 de Lima que tengan un rango de edad entre 18 y 35 años según el estudio de distribución geográfica realizado por CPI. Asimismo, se analizó las características del mercado y la industria de alimentos saludables y se pudo detectar que hay una escasa oferta de productos saludables a base de pota y que hay un segmento de clientes que quiere este tipo de productos y está dispuesto a pagar por él un costo mayor. Para el lanzamiento de este proyecto, se tuvo que realizar diversos presupuestos para poder obtener el costos del negocio y de sus operaciones tanto directas como indirectas, se elaboró un plan de operaciones, plan de marketing, plan de recursos humanos, plan de responsabilidad social empresarial y también luego de varios experimentos y publicaciones en canales digitales para poder vender los productos se realizó el concierge que da pie a una proyección de ventas que nos permitirá hacer una estimación de los ingresos que tendrá Delipota en el transcurso de 3 años. Por último, luego del análisis financiero correspondiente se obtiene que el proyecto tiene una tasa interna de retorno de 61% lo cual nos indica que es rentable y genera valor. / The purpose of the present work is to support a business model whose main line of business is the production and sale of squid burgers breaded with quinoa and kiwicha, a product aimed at people who lead a healthy lifestyle according to Arellano Marketing, belonging to zones 6 and 7 of Lima and that have an age range between 18 and 35 years according to the geographical distribution study conducted by CPI. Likewise, the characteristics of the market and the industry of healthy food were analyzed and it was possible to detect that there is a scarce offer of healthy products based on squid and that there is a segment of clients who want this type of product and are willing to pay a higher cost for it. For the launching of this project, several budgets had to be made in order to obtain the costs of the business and its operations, both direct and indirect. An operations plan, a marketing plan, a human resources plan, a corporate social responsibility plan and also after several experiments and publications in digital channels in order to sell the products, the concierge was made, which gives rise to a sales projection that will allow us to make an estimate of the income that delipota will have in the course of 3 years. Finally, after the corresponding financial analysis, we obtained that the project has an internal rate of return of 61%, which indicates that it is profitable and generates value. / Trabajo de investigación

This thesis contains the results of the extensive study into the synthesis of nickel niobate (NiNb2O6) including the formation of what was a previously unreported polymorph of the material, as well as the magnetic properties of both cobalt niobate (CoNb2O6) and nickel niobate using techniques including SQUID magnetometry, powder and single crystal x-ray scattering, powder and single crystal neutron scattering and muon spin rotation/relaxation. In cobalt niobate we found extremely long relaxation times in the heat capacity which showed up strongly in muon spin rotation experiments but not in neutron measurements. Additionally, with field applied to the system we see the emergence of spin-wave like structures in the neutron scattering data. Within cobalt niobate the strongest interaction is ferromagnetic and along the chain. The chains themselves are laid out on a triangular fashion and interact, although far more weakly, in an antiferromagnetic manner. This triangular patterning as well as an antiferromagnetic interaction results in interchain frustration, which protects the quasi-1D nature of the system due to the difficulty generated in creating 3D order. In nickel niobate we found that growth conditions caused highly variable changes, and we were able to create two different polymorphs. One polymorph was in the same space group as cobalt niobate, which gave us an opportunity to explore the magnetic difference between a spin-½ and spin-1 magnetic system and in nickel niobate in the new space group we performed an ab initio characterization solving the unit cell structure, the magnetic structure with neutron scattering as well as a magnetic characterization with SQUID magnetometry and muon spin rotation, allowing us to contrast the significant crystallographic differences. For the new polymorph we were able to determine its magnetic structure, characterized by Ising-like spins arranged in frustrated tetrahedra with three of the four points lying in the same plane as the spin, and for both materials we were able to use zero-field μSR data to estimate behaviour near the critical point and determine a critical exponent near the magnetic transitions. In both polymorphs there is evidence of constrained magnetism or reduced dimensionality, although the evidence for low dimensionality is much stronger in the columbite polymorph. / Thesis / Doctor of Philosophy (PhD) / This thesis examines two different niobium-based compounds: cobalt niobate (CoNb2O6) and nickel niobate (NiNb2O6). In these systems the cobalt and nickel atoms provide interesting magnetic properties. Within a magnetic material, the magnetic atoms tend to have their spins align in certain ways. The atoms themselves are fixed to particular sites by the way the material is assembled; an atomic framework. In the case of cobalt niobate, the magnetic atoms are arranged in well-separated chains so that a magnetic atom interacts strongly with its magnetic neighbours within a chain, and weakly with ones that are further away. This is an example of a material that is called `low dimensional'. The chains themselves form triangular patterns, and the interactions between chains are both weaker and antialigned, which creates a frustrated competition between the chains, protecting the low dimensional state by creating conditions where it is hard for all the spins in the material to order. For nickel niobate, the magnetic moments all want to anti-align, or be pointing in the opposite direction as its nearest neighbour. The magnetism is `frustrated' because each magnetic atom is tetrahedrally connected to three other atoms, so it cannot meet that condition. This can be visualized by drawing a triangle and trying to make each corner have an arrow pointing up or down. The third corner of the triangle cannot satisfy this requirement for its neighbours (one up and one down arrow). Both decreased dimensionality and frustration can lead to the emergence of novel quantum states of matter at low temperature. This thesis explores these materials with that in mind.

Cette étude porte sur des oxydes TiO2, SrTiO3 et SrZrO3 déficients en oxygène ou dopés par des ions de métaux de transition. Nous avons préparé des échantillons sous forme de polycristaux, de monocristaux et de films minces. Leurs propriétés structurelles, physiques et électroniques ont été mesurées à l’aide de techniques sensibles aux volumes (diffraction des rayons X, magnétométrie SQUID, résonance paramagnétique électronique) ou sensibles aux surfaces (spectroscopie de photoémission, spectroscopie d’absorption X). Les mesures de RPE et au SQUID permettent non seulement d’obtenir leurs propriétés magnétiques mais également la valence des ions Cr dopant. Nous avons ainsi pu établir les paramètres clés qui contrôlent la valence des ions chrome lors de la synthèse. Des phases secondaires telles que SrCrO4 peuvent se former quand les échantillons sont synthétisés dans des atmosphères riches en oxygène. Les propriétés de films SrZrO3 dopés au chrome sont également discutées. Leurs conditions de préparation influencent non seulement le comportement des ions chrome mais également celui de la commutation de résistivité. Ce dernier semble dépendre de la chimie de surface des films. L’accumulation d’ions Cr3+ au voisinage de la surface fournit une interface propre exempte d’oxydes non stœchiométriques. Cette terminaison nette de l’interface a pour résultat de bonnes performances de la commutation de résistivité. / In this study, the oxygen-deficient TiO2, SrTiO3 systems and transition metal ion (Cr or V) doped TiO2, SrTiO3 and SrZrO3 systems have been investigated. We prepared samples as polycrystals, single crystals and thin films for various desires. Their structural, physical and electronic properties were measured by bulk-sensitive techniques (X-Ray Diffraction, SQUID and Electro Paramagnetic Resonance) or surface-sensitive techniques (Photoemission spectroscopy and X-ray absorption spectroscopy). The measurement of SQUID and EPR showed not only their magnetic properties but also the valence state of Cr dopant. We verified the valence state of Cr ions in oxides and found the key parameters of sample synthesis which control the valence state of Cr ions. Segregated phases such as SrCrO4 were formed when the samples were synthesized under O2 rich environment. The surface properties of Cr doped SrZrO3 films are also discussed. We found the synthesis conditions which influence on not only the behavior of Cr ions but also the resistive-switching behaviors. Various resistive-switching behaviors seem to depend on the surface chemistry of films. We found that the accumulation of Cr3+ on film surface provides a clean interface without any non-stoichiometric oxides and that this sharp interface termination results in a good performance of resistive-switching.

Dans la première partie de ce travail de thèse, nous nous sommes intéressé à l’étude de l’anisotropie magnétique au sein de complexes mononucléaires de Ni(II) et de Co(II) pentacoordinés de géométrie allant de la pyramide à base carrée jusqu’à la bipyramide trigonale. Pour les complexes mononucléaires, nous avons montré que pour une géométrie donnée, la nature de l’ion métallique a une influence importante sur l’anisotropie magnétique.Nous avons étudié l’effet de la géométrie pour un même ion métallique. Dans le cas d’une géométrie bipyramidale trigonale (symétrie C3v), nous avons montré que le complexe de Co(II) possède un axe facile de l’aimantation et donc un blocage de l’aimantation qui conduisent à l’ouverture d’un cycle d’hystérèse à basse température. Ce type de complexe peut donc être utilisé pour le stockage de l’information. Dans la deuxième partie du travail, nous avons étudié les propriétés magnétiques de complexes binucléaires. Un complexe binucléaire de Co(II) pontés par deux Cl- présente un faible couplage ferromagnétique et un blocage de l’aimantation.Enfin, l’autre aspect de ce travail est de réaliser une molécule binucléaire où deux ions anisotropes, chacun possédant un axe facile de l’aimantation, soient faiblement couplés de manière antiferromagnétique. Pour ce faire, nous avons étudié des composés avec des ligands de type cryptant où la géométrie autour des Co(II) est bipyramide trigonale. Nous avons trouvé qu’avec un ligand pontant de type Cl- ou Br-, l’interaction d’échange est beaucoup plus importante que l’anisotropie locale des ions Co(II) conduisant à un comportement magnétique où les ions perdent leur caractère local. Ce travail ouvre la perspective de synthétiser le même type de complexes mais avec des ponts de plus grande taille pour diminuer l’intensité du couplage antiferromagnétique. / In the first part of this thesis, we studied the magnetic anisotropy of pentacoordinated mononuclear Ni(II) and Co(II) complexes possessing geometries from square pyramid to trigonal bipyramid. We have shown that, for a given geometry, the metal ion nature has an important influence on the magnetic anisotropy.Then, we studied for a given metal ion the effect of geometry on its magnetic anisotropy. In the case of a trigonal bipyramidal geometry (C3v symmetry), we showed that Co(II) has an Ising type anisotropy (easy axis of magnetization) and thus a blocking of magnetization that leads to an opening of a hysteresis cycle at low temperature. This type of complexes can be used for storing data albeit at low temperature.In the second part of the work, we studied the magnetic properties of binuclear complexes. A binuclear Co(II) complex bridged by two Cl- has a weak ferromagnetic coupling and a blocking of its magnetization.Finally, another aspect of this work was to design binuclear complexes, where two anisotropic ions having each one an easy axis of magnetization, are weakly antiferromagnetically coupled. To do this, we have studied compounds with cryptand ligands where the geometry around the Co (II) is trigonal bipyramid. We found that with a Cl- or Br- bridging ligand, the exchange interaction is much more important than the local anisotropy of Co(II) ions leading to a magnetic behavior where the ions lose their local character. This work opens up prospects for synthesizing the same type of complex but with larger bridges to decrease the intensity of the antiferromagnetic coupling.

No description available.

L'imagerie par résonance magnétique (IRM) est une modalité qui offre de bons contrastes et une bonne résolution spatiale, mais qui souffre d'un important problème de sensibilité. Pour répondre à cette problématique, le paradigme actuel est d'accroitre le champ magnétique des aimants d'IRM. Ceci mène toutefois à une explosion des coûts et à des contraintes accrues vis-à-vis des patients. L'approche que nous présentons est radicalement différente~: il s'agit de travailler à champ faible. Les antennes classiques n'étant pas assez sensibles pour recueillir le signal, l'idée est d'utiliser des SQIF. Ces derniers sont une nouvelle technologie d'antennes supraconductrices ultra-sensibles basées sur les réseaux de SQUID. Le projet vise à optimiser les capteurs SQIF et à les adapter pour la première fois à la RMN afin de mesurer un signal sur un aimant à 0.2~T.Pour ce faire, nous avons développé et étudié les performances de nouvelles architectures d'antennes SQIF afin de définir la géométrie la plus adaptée à la RMN. Nous avons également cherché à mieux comprendre comment le contexte d'utilisation de ces nouvelles antennes pouvait influencer leurs performances. Le jeu d'antennes le plus performant réalisé avait un facteur de transfert de 8.4~kVperT et un seuil de détection de 190~fTperHz. Il fut également observé que la présence d'un champ magnétique pendant le refroidissement de ces capteurs supraconducteurs dégradait leur réponse, phénomène à prendre en compte en RMN.Un Démonstrateur Super-QIF intégrant un SQIF dans l'IRM à 0.2~T fut conçu en tenant compte des contraintes géométriques et de l'environnement magnétique. Après sa fabrication, la température du cryostat était de 50~K, donc suffisante pour le bon fonctionnement des SQIF. Les premiers tests ont montrés que la présence du système ne perturbait pas le signal de RMN.Le démonstrateur est toujours en cours de développement et devrait permettre de mesurer un de RMN dans les mois à venir. À long terme, ces travaux pavent la voie à des applications des SQIF en IRM à champ terrestre. / Magnetic resonance imaging (MRI) is a modality that offers good contrasts and good spatial resolution, but suffers from a significant sensitivity problem. To address this issue, the current paradigm is to increase the magnetic field of MRI magnets. However, this leads to an explosion of costs and to increased constraints on patients. The approach we present is radically different: it involves working in a weak field. As conventional antennas are not sensitive enough to collect the signal, the idea is to use SQIF. These are a new ultra sensitive superconducting antenna technology based on SQUID networks. The project aims to optimize SQIF technology and adapt it to measure an NMR signal in a 0.2~T magnet.To do this, we developed and studied the performance of new SQIF antenna architectures in order to define the geometry most suitable for NMR. We also sought to better understand how the context of use of these new antennas could influence their performance. The best performing antennas set had a transfer factor of 8.4~kVperT and a detection threshold of 190~fTperHz. It was also observed that the presence of a magnetic field during the cooling of these superconducting sensors degraded their response, a phenomenon to be accounted for in NMR.The Super-QIF Demonstrator incorporating a SQIF in the 0.2~T MRI was designed considering the geometric constraints and the magnetic environment. After its assembly, the temperature of the cryostat was 50~K, therefore sufficient for the proper operation of SQIF. The first tests showed that the system presence did not disturb the NMR signal.The demonstrator is still under development and is expected to measure an NMR signal in the forthcoming months. In the long term, this work paves the way for applications of SQIF in Earth's field MRI.

Wetland sites provide important knowledge about settlement history and historical infrastructure in the form of buried archaeological features. However, the subsurface is difficult to access, e.g. due to high groundwater levels or unstable sediments, making archaeological excavation difficult and the conservation of recovered artefacts, e.g. timbers, is expensive. In addition, one of the aims of heritage conservation is to disturb structures in such contexts as little as possible as part of preserving. Therefore, alternative non- and minimal-invasive methods, e.g. geophysical prospection and vibra-coring, are used for exploration. However, geophysical surveys face the issue of inaccurate depth values and rely on sufficient contrasts in the measured physical parameters. Vibra-coring allows direct access to the sediments, but again gives inaccurate depth values due to high compaction rates. For this reason, the implementation of alternative methods and the development of new methodical approaches to wetland site exploration are of extraordinary importance. One such wetland site is the Fossa Carolina, an early medieval canal that today is partially buried. Located in Southern Germany next to Treuchtlingen, south of Nuremberg, the canal was intended at the time to provide a navigable link between the Rhine-Main and Danube basins by bridging the European watershed. In the research for this thesis, direct push sensing was used as an alternative exploration technique to explore the site. In this method, various probes are pushed into the unconsolidated subsoil and the parameters are measured in situ with high depth accuracy. (i) Therefore, the colour logging tool (CLT) and the electrical conductivity (EC) probe were applied. (ii) In order to record archaeological structures and features, the soundings were distributed closely along a transect using an adaptive exploration strategy, thus recording a high-resolution cross-section of the structure. (iii) These prospections were integrated into a spatial-hierarchical multi-method approach by combining direct push sensing with geophysical survey and vibra-coring, inter alia. (iv) Thus, a deeply buried section of the Fossa Carolina (West-East Section) was explored, demonstrating at least one-way navigability and revealing the backfill stratigraphy. (v) Furthermore, the approach used helped to clarify the nature of conspicuous magnetic anomalies in the area adjacent to the canal. In the Northern and North-Eastern Sections, magnetic anomalies provided evidence of water-supplying structures. The exploration of these structures revealed an Early Holocene structure in the North-Eastern Section and a historic gravel road in the Northern Section. (vi) Additionally, a strong magnetic anomaly with a course parallel to the canal in the Northern Section could be temporally and stratigraphically associated with the construction of the canal. Thus, for the first time, a larger remnant of the construction process outside the canal could be identified, even if the origin could not be conclusively clarified. (vii) In a broader context, the in situ direct push cross-sections were integrated into a 3D modelling approach for the entire Fossa Carolina to quantify the excavation volume. (viii) The methodological approach was successfully applied to a wetland site at Pestenacker in Southern Germany to collect evidence for Holocene floodplain dynamics in the Late Neolithic settlement. Finally, the thesis demonstrates the enormous methodological potential of direct push sensing for the exploration of buried archaeological sites. In particular, the colour logging tool is proving to be extremely effective, further enhanced by the intelligent combination in multi-method approaches. This is confirmed by the significant results obtained at Fossa Carolina that shed new light on the canal{'}s navigability, water supply, and construction structure. Overall, this thesis demonstrates the valuable contribution that direct push methods can make to geoarchaeological research. It both introduces a new methodological approach and provides new empirical evidence concerning the construction of an example of early medieval infrastructure.:Preface Acknowledgements Abstract Kurzfassung Contents List of Figures List of Tables Acronyms and Symbols 1 Introduction 1.1 Geoarchaeological exploration in wetlands: possibilities and challenges 1.1.1 Proven exploration methods 1.1.2 Direct push sensing 1.1.3 Exploration strategies 1.2 The study site 1.2.1 The Fossa Carolina - State of the art in brief 1.2.2 Natural settings 1.3 Aims of the thesis 2 Published Studies 2.1 Minimalinvasive Direct-push-Erkundung in der Feuchtboden(geo)archäologie am Beispiel des Karlsgrabens (Fossa Carolina) 2.2 Non-invasive prospection techniques and direct push sensing as high-resolution validation tools in wetland geoarchaeology – Artificial water supply at a Carolingian canal in South Germany? 2.3 High-Resolution Direct Push Sensing in Wetland Geoarchaeology—First Traces of Off-Site Construction Activities at the Fossa Carolina 2.4 3D-Modelling of Charlemagne’s Summit Canal (Southern Germany)—Merging Remote Sensing and Geoarchaeological Subsurface Data 2.5 A hydrological tipping point and onset of Neolithic wetland occupation in Pestenacker (Lech catchment, S Germany) 3 Discussion 3.1 Direct push sensing for wetland exploration 3.1.1 High-resolution direct push sensing cross-sections 3.1.2 Integration and comparison of direct push sensing in a spatially hierarchical multi-method approach 3.1.3 Direct push colour logging tool (CLT) data for ground truthing 3.1.4 Perspectives on direct push sensing in geoarchaeology 3.2 Results of the exploration of the Fossa Carolina 3.2.1 Chronostratigraphic recording in the West-East and Northern Sections 3.2.2 Characteristics of the canal construction in the West-East and Northern Sections 3.2.3 Validation of off-canal structures in the Northern and North-Eastern Sections 3.2.4 Water supply for the Fossa Carolina 3.2.5 Pending issues in the study of the Fossa Carolina 4 Conclusion References Appendix A1 - Author publications A2 - Article contribution A3 - Declaration of originality A4 - Bibliographic description / Feuchtgebiete bergen durch begrabene archäologische Strukturen wichtige Erkenntnisse zur Siedlungsgeschichte und historischen Infrastruktur. Schwierige Untergrundverhältnisse, z. B. durch hohen Grundwasserspiegel oder instabile Sedimente, erschweren jedoch archäologische Ausgrabungen und die Konservierung der geborgenen Artefakte, z. B. Hölzer, verursacht hohe Kosten. Darüber hinaus ist ein Ziel der Bodendenkmalpflege, archäologische Strukturen so wenig wie möglich zu beeinträchtigen und sie in situ zu erhalten. Daher werden alternative nicht- und minimal-invasive Methoden, z. B. geophysikalische Prospektionen und Rammkernsondierungen, zur Exploration eingesetzt. Bei geophysikalischen Untersuchungen ergeben sich jedoch Schwierigkeiten durch ungenaue Tiefenwerte und die Methoden sind auf ausreichende Kontraste der gemessenen physikalischen Parameter angewiesen. Rammkernsondierungen ermöglichen einen direkten Zugriff auf die Sedimente, erzeugen jedoch wiederum ungenaue Tiefenwerte durch hohe Kompaktionsraten. Aus diesem Grund sind die Implementierung alternativer Methoden und die Entwicklung neuer methodischer Ansätze für die Erforschung von Feuchtgebietsstandorten von herausragender Bedeutung. Die Fossa Carolina, ein frühmittelalterlicher, heute teilweise verschütteter Kanal, ist ein solcher Standort. Das Bauwerk befindet sich in Süddeutschland in der Nähe von Treuchtlingen, südlich von Nürnberg und sollte eine schiffbare Verbindung zwischen dem Rhein-Main- und dem Donaueinzugsgebiet herstellen, indem es die europäische Hauptwasserscheide überbrückte. Zur Erkundung des Bauwerks wurde als Alternative die in situ Direct-Push-Methode eingesetzt. Bei dieser Methode werden verschiedene Sonden in den unkonsolidierten Untergrund gedrückt und die Parameter in situ tiefengenau gemessen. (i) Dabei kamen die Farbsonde, engl. colour logging tool (CLT), und die Sonde zur Messung der elektrischen Leitfähigkeit, engl. electrical conductivity (EC) probe, zum Einsatz. (ii) Zur Erfassung archäologischer Strukturen und Befunde wurden die Sondierungen mit einer adaptiven Erkundungsstrategie auf einem Transekt engmaschig verteilt und somit ein hochaufgelöster Querschnitt des Bauwerks erfasst. (iii) Darüber hinaus wurden diese Prospektionen in einen räumlich-hierarchischen Multimethodenansatz integriert, indem in situ Direct-Push-Sondierungen mit z. B. geophysikalischen Erkundungen und Rammkernsondierungen kombiniert wurden. Somit wurde (iv) ein tiefliegender, begrabener Abschnitt der Fossa Carolina im West-Ost-Bereich erkundet, dort die Schiffbarkeit für mindestens eine Schiffsbreite nachgewiesen und die Sedimentstratigraphie der Verfüllung beschrieben. Weiterhin wurde der Ansatz genutzt, um magnetische Anomalien im Umfeld des Kanals zu prospektieren. (v) Im nördlichen und nordöstlichen Bereich lieferten magnetische Anomalien Hinweise auf wasserzuführende Bauwerke im Untergrund. Die Erkundung ergab eine frühholozäne Struktur im nordöstlichen Bereich und eine historische Schotterstraße im nördlichen Bereich. (vi) Weiterhin konnte eine starke magnetische Anomalie mit parallelem Verlauf zum Kanal im nördlichen Bereich zeitlich und stratigraphisch dem Bauwerk zugeordnet werden. Somit konnte zum ersten Mal eine größere Spur des Baus außerhalb des Kanals nachgewiesen werden, auch wenn die Entstehung nicht abschließend geklärt werden konnte. (vii) Im übergeordneten Kontext konnten die Daten der in situ Direct-Push-Transekte in einen 3D-Modellierungsansatz für die gesamte Fossa Carolina zur Quantifizierung des Aushubs integriert werden. (viii) Neben der Erforschung der Fossa Carolina wurde der methodische Ansatz zusätzlich an einem Feuchtgebietsstandort bei Pestenacker in Süddeutschland angewendet, um Informationen über die holozäne Auendynamik an der spätneolithischen Siedlung zu gewinnen. Schlussendlich belegt die Dissertation das enorme methodische Potential der in situ Direct-Push-Erkundungen für die Prospektion von Bodendenkmälern. Dabei erweist sich insbesondere die Farbsonde als äußerst wirkungsvoll, was durch die gezielte Kombination in multi-methodischen Ansätzen noch verstärkt wird. Dies wird durch die aussagekräftigen Ergebnisse an der Fossa Carolina belegt, mit deren Hilfe insbesondere neue Erkenntnisse zur Schiffbarkeit, Wasserzuführung und Baustruktur gewonnen werden konnten. Insgesamt demonstriert diese Dissertation den wertvollen Beitrag, den in situ Direct-Push-Methoden zur geoarchäologischen Forschung leisten können. Sie präsentiert sowohl einen neuen methodischen Ansatz als auch neue empirische Erkenntnisse zu einem frühmittelalterlichen Bauwerk.:Preface Acknowledgements Abstract Kurzfassung Contents List of Figures List of Tables Acronyms and Symbols 1 Introduction 1.1 Geoarchaeological exploration in wetlands: possibilities and challenges 1.1.1 Proven exploration methods 1.1.2 Direct push sensing 1.1.3 Exploration strategies 1.2 The study site 1.2.1 The Fossa Carolina - State of the art in brief 1.2.2 Natural settings 1.3 Aims of the thesis 2 Published Studies 2.1 Minimalinvasive Direct-push-Erkundung in der Feuchtboden(geo)archäologie am Beispiel des Karlsgrabens (Fossa Carolina) 2.2 Non-invasive prospection techniques and direct push sensing as high-resolution validation tools in wetland geoarchaeology – Artificial water supply at a Carolingian canal in South Germany? 2.3 High-Resolution Direct Push Sensing in Wetland Geoarchaeology—First Traces of Off-Site Construction Activities at the Fossa Carolina 2.4 3D-Modelling of Charlemagne’s Summit Canal (Southern Germany)—Merging Remote Sensing and Geoarchaeological Subsurface Data 2.5 A hydrological tipping point and onset of Neolithic wetland occupation in Pestenacker (Lech catchment, S Germany) 3 Discussion 3.1 Direct push sensing for wetland exploration 3.1.1 High-resolution direct push sensing cross-sections 3.1.2 Integration and comparison of direct push sensing in a spatially hierarchical multi-method approach 3.1.3 Direct push colour logging tool (CLT) data for ground truthing 3.1.4 Perspectives on direct push sensing in geoarchaeology 3.2 Results of the exploration of the Fossa Carolina 3.2.1 Chronostratigraphic recording in the West-East and Northern Sections 3.2.2 Characteristics of the canal construction in the West-East and Northern Sections 3.2.3 Validation of off-canal structures in the Northern and North-Eastern Sections 3.2.4 Water supply for the Fossa Carolina 3.2.5 Pending issues in the study of the Fossa Carolina 4 Conclusion References Appendix A1 - Author publications A2 - Article contribution A3 - Declaration of originality A4 - Bibliographic description

The work presented in this thesis was broadly focussed on the investigation of the magnetic behaviour of different superconducting materials in the form of bulk (singe crystals and pellets) and thin films (nanomagnetic devices like superconducting spin valves etc). Neutrons and muons were extensively used to probe the structural and magnetic behaviour of these systems at the nanoscale along with bulk characterisation techniques like high-sensitive magnetic property measurements, scanning probe microscopy and magneto-transport measurements etc. The nanoscale interplay of Superconductivity and Ferromagnetism was studied in the thin film structures using a combination of Polarised Neutron Reflectivity (PNR) and Low Energy Muon Spin Rotation (LE-µSR) techniques while bulk Muon Spin Rotation (µSR) technique was used for microscopic magnetic investigation in the bulk materials. In the Fe/Pb heterostructure, evidence of the Proximity Effect was observed in the form of an enhancement of the superconducting penetration depth (λs) with an increase in the ferromagnetic layer thickness (dF) in both the bilayered and the trilayered structures. The existence of an Inverted Magnetic Region was also detected at the Ferromagnet-Superconductor (F/S) interface in the normal state possibly originating from the induced spin polarisation within the Pb layer in the presence of the neighbouring Fe layer(s). The spatial size (height and width) of the Inverted Magnetic Region did not change much while cooling the sample below the superconducting transition temperature(Tc)and it also stayed unaffected by an increase in the Fe layer thickness and by a change of the applied magnetic field. In the superconducting spin valve structure containing Permalloy (Py) as ferromagnetic layer and Nb as the superconducting layer, LE-µSR measurements revealed the evidence of the decay of magnetic flux density (as a function of thickness) within the Nb layer symmetrically from the Py/Nb interfaces towards the centre of the Nb layer in the normal state. The thickness dependent magnetisation decay occurred over two characteristic length scales in the normal state that stayed of similar values in the superconducting state also. In the superconducting state, an additional contribution towards the magnetisation was found in the vicinity of the Py/Nb interfaces possibly originating from the spin polarisation of the singlet Cooper pairs in these areas. The nanoscale magnetic investigation on a highly engineered F/S/F structure (where each of the F blocks made of multiple Co/Pd layers with magnetic moments aligned perpendicular to the plane of these layers and neighbouring magnetic blocks separated by Ru layers giving rise to antiferromagnetic alignment) using LE-µSR showed an antisymmetric thickness dependent magnetic flux density profile with two characteristic length scales. In the superconducting state, the magnetic flux density profile got modified within the superconducting Nb₆₇Ti₃₃ layer near the F/S interfaces in a way similar to that of observed in the case of Py/Nb system, most likely because of the spin polarisation of the superconducting electron pairs. The vortex magnetic phase diagram of Bi₂Sr₂Ca₂Cu₃O10-δ was studied using the Muon Spin Rotation (µSR) technique to explore the effects of vortex lattice melting and rearrangements for vortex transitions and crossover as a function of magnetic field and temperatures. At low magnetic fields, the flux vortices undergo a first order melting transition from a vortex lattice to a vortex liquid state with increasing temperature while another transition also occurred with increasing field at fixed temperature to a vortex glass phase at the lowest temperatures. Evidence of a frozen liquid phase was found in the intermediate field region at low temperature in the form of a lagoon in the superconducting vortex state which is in agreement with earlier observations made in BiSCCO-2212. The magnetic behaviour of the unconventional superconductor Sr₂RuO₄ was investigated using µSR to find the evidence of normal state magnetism and the nature of the vortex state. In the normal state, a weak hysteretic magnetic signal was detected over a wide temperature and field range believed to be supporting the evidence of a chiral order parameter. The nature of the vortex lattice structure was obtained in different parts of the magnetic phase diagram and the evidence of magnetic field driven transition in the lattice structure was detected from a Triangular→Square structure while the vortex lattice stayed Triangular over the entire temperature region below Tc at low fields with a disappearance of pinning at higher temperatures.

Les travaux présentés dans cette thèse sont consacrés à l'investigation du fonctionnement des technologies bipolaires, et plus particulièrement des technologies BiCMOS SiGe, pour une utilisation à température cryogénique. Un état de l'art sur les transistors bipolaires et les bruits électroniques que l'on rencontre sur ce genre de technologie sont donnés avec une approche orientée vers les basses températures. Ces rappels permettent d'aborder les mesures, des paramètres basse fréquence et du bruit, réalisées sur des transistors bipolaires silicium et sur deux technologies SiGe à 300 K, 77 K et 4.2 K. Il est ensuite présenté deux réalisations d'ASIC cryogénique en technologie standard BiCMOS SiGe. La première est un amplificateur bas bruit (1 nV/sqrtHz) et large bande (1 GHz) fonctionnant à 77 K. Il est destiné à la caractérisation de bolomètres supraconducteurs YBaCuO à électrons chauds. La seconde réalisation est un circuit de lecture et de multiplexage de matrice de SQUID. Il est, en particulier, présenté le développement, la réalisation et le test d'un amplificateur ultra bas bruit (0.2 nV/sqrtHz) avec deux entrées multiplexées fonctionnant à 4.2 K.

Lulas da família Loliginidae são recursos pesqueiros em crescente importância no ecossistema marinho da Plataforma Continental Sudeste (PCSE) do Brasil. No entanto, informações sobre a distribuição dos estágios iniciais do seu ciclo de vida são bastante escassas. Com base em amostras de plâncton coletadas por 11 cruzeiros oceanográficos pretéritos do Instituto Oceanográfico da USP entre 1991 e 2005, o presente estudo teve como objetivo a identificação da ocorrência de paralarvas de Loliginidae na região entre o Cabo de São Tomé (RJ) e Cananéia (SP). Das 644 amostras analisadas, foram encontradas 246 paralarvas, sendo 121 identificadas em nível de espécie (Doryteuthis sanpaulensis n=75, Doryteuthis plei n=39, Lolliguncula brevis n=6 e Pickfordiateuthis pulchella, n=1). Os padrões de distribuição da Família em relação aos processos oceanográficos foram identificados a partir de mapas de distribuição horizontal e vertical de abundância, temperatura e salinidade. Modelos Lineares Generalizados (GLMs) foram utilizados para detectar os fatores que explicariam a ocorrência e a abundância de Loliginidae, os quais indicaram que a profundidade e a temperatura superficial do mar são as principais variáveis explanatórias. Uma Análise de Redundância (RDA) evidenciou os principais padrões de distribuição observados das três principais espécies de Loliginidae em relação às variáveis oceanográficas. D. sanpaulensis predominou na região norte da área de estudo, associada a águas frias e a eventos de ressurgência. D. plei ocorreu principalmente na região sul da área e em águas mais quentes. L. brevis foi encontrada apenas na região estuarina de Santos, em águas rasas e menos salinas. Os resultados obtidos representam uma contribuição relevante ao conhecimento sobre a Oceanografia Pesqueira das lulas no ecossistema marinho regional. / Loliginid squids are fisheries resources of increasing importance in the shelf ecosystem of Southeastern Brazil. Therefore, information about distribution of the early stages of their life cycle is scarce. Based on plankton samples collected by eleven historical oceanographic surveys cruises of the University of São Paulo\'s Oceanographic Institute between 1991 and 2005, the present study aimed identification of the occurrence of Loliginidae paralarvae in the region between Cabo de São Tomé (22ºS) and Cananéia (25ºS). From 664 samples analyzed, 246 paralarvae were found, being 121 identified to the species level, (Doryteuthis sanpaulensis n=75, Doryteuthis plei n=39,, Lolliguncula brevis n=6 and Pickfordiateuthis pulchella, n=1). The distributional patterns of Loliginidae in relation to oceanographic processes were identified by using horizontal and vertical maps of abundance, temperature and salinity. Generalized Linear Models (GLMs) were used to detect the factors that explain Loliginidae occurrence and abundance, which indicated that depth and sea surface temperature, were major explanatory variables. A Redundancy Analyses (RDA) showed the main observed distribution patterns of the three species of Loliginidae in relation to oceanographic variables. D. sanpaulensis occurred in the northern region associated to cold waters and upwelling events. D. plei occurred mainly in the southern region of the study area and in warmer waters.L. brevis was found in the estuarine region of Santos, in shallow and low salinity waters. The obtained results represent a relevant contribution to squids Fisheries Oceanography in the regional marine ecosystem.