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Université de Fribourg

Novel iron tweezers complexes for hydrogenation and polymerization of olefins

Mafua, Roger ; Jenny, Titus A. (Dir.)

Thèse de doctorat : Université de Fribourg, 2006 ; no. 1503.

The use of organometallic complexes as catalysts became a very significant topic in the field of material chemistry. However, despite of this development, only few of them contain iron(II), except the tridentate complex diimine pyridine developed by Gibson and Brookhart and employed in the olefin polymerization. Unfortunately, this model suffers by its lack of tolerance towards the minor changes...

Université de Neuchâtel

Partner control mechanisms in repeated social interactions

Wubs, Matthias ; Bshary, Redouan (Dir.) ; Lehmann, Laurent (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2017.

Individuals that interact socially regularly have to make decisions whether to help another individual (provide some payoff benefit, possible at a personal payoff cost) or not. Here, a pair of individuals is best off if both individuals help each other, but a single individual may gain a relative payoff advantage by not helping (defecting) while the partner does choose to help, thus creating a...

Université de Neuchâtel

Evolution of moonwort ferns ("Botrychium", Ophioglossaceae) on local to global scales

Dauphin, Benjamin ; Grant, Jason (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2017.

Plants have long fascinated biologists by their ability to form cryptic species, hybrids between distinct species, large and stable genome sizes, and a wide variety of mating systems among taxa that have driven to the current plant biodiversity. More than 450 million year ago, vascular plants emerged and colonized the land. Rapidly, they dispersed to explore new habitats and diversified in...

Université de Neuchâtel

Complexity of positive contactomorphisms

Dahinden, Lucas ; Schlenk, Felix (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2018.

In this thesis we study volume growth properties of positive contactomorphisms, using Rabinowitz-Floer homology. We prove that positive dimensional growth of Rabinowitz-Floer homology implies that every positive contactomorphism has positive topological entropy. We found two instances where Rabinowitz-Floer homology has positive dimensional growth. The first instances are unit cosphere bundles of...

Université de Neuchâtel

Application of carbon-chlorine isotopic analysis to determine the origin and fate of chlorinated ethenes in groundwater

Badin, Alice ; Hunkeler, Daniel (Dir.) ; Schirmer, Mario (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2015.

Chlorinated ethenes are ubiquitous groundwater contaminants posing a threat to one of our main drinking water sources. Despite their spill history dating back to more than 40 years ago, these contaminants are still found in groundwater in numerous industrially developed countries due to their persistence, difficult characterisation in the subsurface and resulting challenging remediation. When...

Université de Neuchâtel

An explicit approach to the Baum-Connes conjecture for some semi-direct products

Pooya, Sanaz ; Valette, Alain (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2018.

We investigate the Baum-Connes assembly map through concrete examples. It is known that the Baum-Connes conjecture holds for large classes of groups including a-T-menable groups, thanks to work of Higson and Kasparov. However neither of these works describes the K-groups. In this thesis we describe explicitly the Baum-Connes assembly map for some a-T-menable groups namely BS(1, n), where...

Université de Neuchâtel

Fungal biogenic patina : optimization of an innovative conservation treatment for copper-based artefacts

Albini, Monica ; Joseph, Edith (Dir.) ; Junier, Pilar (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2017.

Microorganisms are often considered harmful for cultural heritage. However, they can also be used for its safeguarding. Indeed, some fungal species are known for their ability to produce oxalic acid in order to immobilize of toxic heavy metals and, therefore, detoxify their environmental. Biotechnology already exploited this ability to immobilize heavy metals in the field of waste treatment...

Université de Neuchâtel

Numerical simulations and uncertainty analysis for assessing spatial and temporal dynamics in alluvial river-aquifer systems : an application in the context of the 3rd Rhône River Correction

Gianni, Guillaume ; Brunner, Philip (Dir.) ; Perrochet, Pierre (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2017.

Characterizing river-groundwater interactions in alluvial aquifers is essential when forecasting the impact of river management strategies, such as river restorations, on the overall water resources distribution and dynamics. Therefore, the development of methods and calibration approaches that allow for better identification of the spatial and temporal characteristics of the hydraulic properties...

Université de Neuchâtel

Compact ultrafast frequency combs

Hakobyan, Sargis ; Südmeyer, Thomas (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2018.

Optical frequency combs provide a direct and phase-coherent link between the optical spectral region of the electromagnetic spectrum (i.e., hundreds of THz frequencies) and the radio-frequency domain (MHz-GHz frequencies). As a result, they constitute a unique and powerful tool for various applications such as broadband high-resolution molecular spectroscopy, optical metrology, astrophysics,...

Université de Neuchâtel

Novel ultrafast high-power thin-disk laser oscillators and applications for metrology and XUV generation

Paradis, Clément ; Südmeyer, Thomas (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2018.

Ultrafast lasers have revolutionized research in fundamental physics, chemistry and biology as well as industrial applications. A great number of experiments benefit from the development of Yb-based high-power femtosecond laser sources. These systems typically include a low-power mode-locked oscillator followed by amplifier stages relying on fiber, slab or thin-disk technologies. In many cases,...