Université de Fribourg

Paléoécologie et taphonomie comparative en milieux carbonatés peu profonds (oxfordien du Jura suisse et holocène du Belize)

Stienne, Noémie ; Strasser, Andreas (Dir.)

Thèse de doctorat : Université de Fribourg, 2010 ; no 1661.

Sediment on tropical platforms stems from terrigeneous sources and from authigenic carbonate production, and the accumulation is also influenced by lateral migration of sedimentary bodies. The qualitative and quantitative evolution of the sediment flow is controlled by allocyclic and autocyclic processes. The studies of Pittet (1996), Plunkett (1997), Dupraz (1999), Hug (2003), and Védrine...

Université de Fribourg

Magnetic induction in high-Tc superconductor/ferromagnet heterostructures

Hoppler, Justin ; Bernhard, Christian (Dir.)

Thèse de doctorat : Université de Fribourg, 2009 ; Nr. 1638.

The magnetic induction in superlattices comprising thin layers of the high-Tc superconductor YBa2Cu3O7 (YBCO) and the ferromagnet La2/3Ca1/3MnO3 (LCMO) has been investigated by polarised neutron reflectometry measurements. The data provide evidence for a surprisingly strong mutual interaction of the superconducting and the ferromagnetic order parameters. In the region of the interfaces a...

Université de Fribourg

Electron-driven chemistry of saturated compounds containing oxygen or nitrogen atoms

Ibănescu, Bogdan Cătălin ; Allan, Michael (Dir.)

Thèse de doctorat : Université de Fribourg, 2009.

The broad aim of the present work was to improve our understanding of dissociative electron attachment (DEA) processes mediated by Feshbach resonances. DEA represents an important class of processes leading to electron-driven chemical change. Depending on the nature of the resonance (the transient negative ion) which mediates it, DEA processes can be divided into several types. Out of these, the...

Université de Fribourg

The influence of light on the circadian clock of mice and men

Jud, Corinne ; Albrecht, Urs (Dir.)

Thèse de doctorat : Université de Fribourg, 2009 ; Nr. 1625.

The continuous light-dark cycles caused by the rotation of the Earth around its own axis facilitated the evolution of circadian clocks, which have a huge impact on our daily life. Deregulation of the internal clock can lead to sleeping disorders, depression and various other health problems. Thus it is important to understand the mechanisms which allow our clock to tick properly. Since circadian...

Université de Fribourg

Applications of statistical physics to complex systems

Medo, Matúš ; Zhang, Yi-Cheng (Dir.)

Thèse de doctorat : Université de Fribourg, 2008 ; no 1614.

Knowledge and information make our lives easier and more enjoyable. In this thesis we use techniques and concepts from statistical physics and probability theory to explore several models of complex systems where information plays a prominent role. When building these models we tried to capture main aspects of real systems but also to keep the models simple and analytically solvable. We begin the...

Université de Fribourg

Elasticity and dynamics of weakly aggregated colloidal systems

Clara Rahola, Joaquim ; Trappe, Véronique (Dir.) ; Bartsch, Eckhard (Codir.) ; Schurtenberger, Peter (Codir.)

Thèse de doctorat : Université de Fribourg, 2007 ; no 1557.

In this work we present an experimental study on the elastic and dynamic properties of a variety of colloidal particle suspensions, in which the intrinsic Van der Waals attraction between the particles is modulated by providing the particle with a steric stabilization layer. We use different destabilization methods to trigger aggregation and study the physical properties of the resulting...

Université de Fribourg

External background radiation in the Fribourg (Switzerland) urban area

Boucher, Mathieu ; Völkle, Hansruedi (Dir.) ; Jenny, Titus (Codir.)

Thèse de doctorat : Université de Fribourg, 2008 ; no 1599.

We are constantly exposed to ionizing radiation of different type. Most of the radiation exposure comes from natural sources. External background ° radiation originates from two different sources, terrestrial and cosmic. Terrestrial radiation originates from two different background, natural and artificial or “man-made” isotopes. The artificial radiation contributes very little to the total...

Université de Fribourg

Characterization of chrysotile, tellurium and iImogolite nanotubes

Métraux, Cédric ; Grobéty, Bernard (Dir.) ; Jenny, Titus (Codir.)

Thèse de doctorat : Université de Fribourg, 2008.

The discovery of C60 (R. Smalley et al.) and carbon nanotubes CNTs (S. Iijima) in 1985 and 1991 respectively was a milestone in the field of nanoscience. Since 1991, WS2, MoS2, BN, Se, Te nanotubes were synthesized and analyzed. These nanotubes are promising materials for many applications in the field of catalysis, electronic, polymer synthesis, etc. In this study, we characterized the...

Université de Fribourg

Spectroscopic, time-resolved, and Stark effect studies of alkali atoms and exciplexes in solid ⁴He

Hofer, Adrian ; Weis, Antoine (Dir.) ; Bally, Thomas (Codir.) ; Ernst, Wolfgang E. (Codir.)

Thèse de doctorat : Université de Fribourg, 2007 ; Nr. 1571.

This thesis work was carried out in the atomic physics group of the Physics Department of the University of Fribourg. The thesis is divided into two main parts, and contains in total six original research papers. The first part deals with purely optical studies of Cs and Rb atoms and their exciplex molecules and clusters implanted in solid 4He crystals. The second part is an experimental and...