Université de Fribourg

Hydrogen storage properties of Mg[BH₄]₂

Matsunaga, Tomoya ; Buchter, Florian ; Mauron, Phillipe ; Bielmann, Michael ; Nakamori, Y. ; Orimo, S. ; Ohba, N. ; Miwa, K. ; Towata, S. ; Züttel, Andreas

In: Journal of Alloys and Compounds, 2008, vol. 259, no. 1-2, p. 583-588

Among the large variety of possible complex hydrides only few exhibit a large gravimetric hydrogen density and stability around 40 kJ mol⁻¹H₂. Mg[BH₄]₂ is based on theoretical approaches a complex hydride with an equilibrium hydrogen pressure of approximately 1 bar at room temperature and a hydrogen content of 14.9 mass%. The reaction of Li[BH₄] with MgCl₂ at elevated temperatures...

Université de Fribourg

Charge-density oscillation on graphite induced by the interference of electron waves

Ruffieux, Pascal ; Melle-Franco, M. ; Gröning, Oliver ; Bielmann, Michael ; Zerbetto, F. ; Gröning, Pierangelo

In: Physical Review B, 2005, vol. 71, p. 153403

We report on a pronounced redistribution of the local electronic density of states at the graphite surface, which is induced by the presence of low energy hydrogen-ion induced point defects. Scanning tunneling microscopy reveals standing waves in the local density of states, which are due to backscattering of electron wave functions at individual point defects. The superstructure thereby formed...

Université de Fribourg

Surface scientific aspects of material relevant to tribology

Bielmann, Michael ; Gröning, Pierangelo (Dir.) ; Schlapbach, Louis (Codir.)

Thèse de doctorat : Université de Fribourg, 2004 ; no 1467.

Die vorgestellten Arbeiten behandeln oberflächenphysikalische Aspekte ausgewählter Materialien deren Anwendung aus tribologischer Sicht relevant sind. Tribologie ist ein hochgradig interdisziplinäres Thema und eines der ältesten Probleme, die den denkenden Menschen beschäftigen. Obwohl die Wichtigkeit der Oberfläche in der Tribologie wahrgenommen und akzeptiert wird, bleibt das Verständnis...