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Université de Fribourg

Dendrogeomorphologische Prozessanalyse zum Schwemmholzaufkommen und Rekonstruktion von Ufererosion zweier voralpiner Wildbachsysteme

Hitz, Oliver Markus ; Monbaron, Michel (Dir.) ; Strunk, Horst (Codir.)

Thèse de doctorat : Université de Fribourg, 2008 ; Nr. 1605.

En raison du changement climatique global, il faut s’attendre à l’avenir à une augmentation des événements de fortes précipitations régionales. La Suisse subit également chaque année des dégâts dus aux intempéries, conséquences directes d’événements pluviométriques exceptionnels. Les dégâts sont causés par exemple par l’érosion et l’accumulation de sédiments...

Université de Fribourg

The birth of the Rheic Ocean — Early Palaeozoic subsidence patterns and subsequent tectonic plate scenarios

Raumer, Jürgen F. von ; Stampfli, Gérard M.

In: Tectonophysics, 2008, vol. 461, no. 1-4.1, p. 9-20

New plate-tectonic reconstructions of the Gondwana margin suggest that the location of Gondwana-derived terranes should not only be guided by the models, but should also consider the possible detrital input from some Asian blocks (Hunia), supposed to have been located along the Cambrian Gondwana margin, and accreted in the Silurian to the North-Chinese block. Consequently, the Gondwana margin has...

Université de Fribourg

Thermal runaway of dried sewage sludge granules in storage tanks

Poffet, Martine S. ; Käser, Kurt ; Jenny, Titus A.

In: Chimia, 2008, vol. 62, no. 1-2, p. 29-34

Elimination of the sewage sludge from urban wastewater occurs exclusively by incineration in Switzerland, because recycling as fertilizer in agriculture has been banned since October 2006. Two options exist for elimination, either thermal elimination of a thickened sludge in a household waste incineration plant, or drying of the thickened sludge to yield a granular material fit for storage and...

Université de Fribourg

Silver coordination compounds as light-stable, nano-structured and anti-bacterial coatings for dental implant and restorative materials

Slenters, Tünde Vig ; Hauser-Gerspach, Irmgard ; Daniels, Alma U. ; Fromm, Katharina M.

In: Journal of Materials Chemistry, 2008, vol. 18, p. 5359-5362

Silver coordination polymer chains were deposited on Au(111) as a model surface, as well as on gold alloy and titanium as dental implant and restorative materials. The topography of the surface was analysed on the model substrate and it was found to be a nano-structured crystalline material. In vitro investigations in a flow chamber imitating the oral environment prove the anti-bacterial...

Université de Fribourg

Counterion effect on the formation of coordination polymer networks between AgNO₃ and L (2,2′-oxybis(ethane-2,1-diyl) diisonicotinate) Part 2

Sague, Jorge L. ; Meuwly, Markus ; Fromm, Katharina M.

In: CrystEngComm, 2008, vol. 10, p. 1542-1549

Herein we report the synthesis and characterization by single crystal X-ray diffraction of three new silver(I) complexes {[Ag₂·L₂](NO₃)₂(H₂O)₄} (1), {[Ag₂·L₂](NO₃)₂} (2) and {[Ag₂·L₂](NO₃)₂} (3). Whereas compounds 2 and 3 are...

Université de Fribourg

Resonance structure in low-energy electron scattering from OCS

Hoffmann, T. H. ; Hotop, H. ; Allan, Michael

In: Journal of Physics B: Atomic, Molecular and Optical Physics, 2008, vol. 41, no. 9, p. 195202

Energy-dependent absolute angle-differential cross sections (θ = 135°) for elastic and vibrationally inelastic electron scattering from OCS molecules have been investigated at high resolution (13 meV). The elastic cross section, reported over the range E= 0.06–20 eV, exhibits a deep Ramsauer–Townsend minimum near 0.55 eV and the π*(1.2 eV) and σ*(3.8 eV) resonances known from...

Université de Fribourg

Probing the potential of N-heterocyclic carbenes in molecular electronics: redox-active metal centers interlinked by a rigid ditopic carbene ligand

Mercs, Laszlo ; Neels, Antonia ; Albrecht, Martin

In: Dalton Transactions, 2008, vol. 41, p. 5570-5576

Bimetallic homonuclear iron(II) and ruthenium(II) N-heterocyclic carbene complexes have been synthesized and crystallographically analyzed. As a spacer ligand for interconnecting the two redox-active metal centers, a ditopic carbene ligand has been used that comprises two carbene sites annelated to benzene. Detailed electrochemical and spectroelectrochemical analyses of the bimetallic...

Université de Fribourg

Palladation of diimidazolium salts at the C4 position: access to remarkably electron-rich palladium(II) centers

Heckenroth, Marion ; Kluser, Evelyne ; Neels, Antonia ; Albrecht, Martin

In: Dalton Transactions, 2008, p. 6242 - 6249

Palladation of C2-protected diimidazolium salts with Pd(OAc)₂ afforded complexes comprising C4-bound N-heterocyclic dicarbene ligands. The reactivity of these complexes towards Lewis acids (AgBF₄, AgOAc) and Brønsted acids (H₂SO₄, H₃PO₄, HOAc) revealed that abnormal C4 bonding of the carbenes markedly increases the nucleophilicity of the coordinated palladium center as compared to C2...

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