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Université de Fribourg

Spectroscopy of alkali-metal atoms in dense supercritical ⁴He at low temperatures

Moroshkin, Peter ; Lebedev, Victor ; Weis, Antoine

In: Physical Review A, 2013, vol. 87, no. 2, p. 022513

We present an experimental study of laser-induced fluorescence spectra of Cs atoms embedded in superfluid and solid ⁴He, as well as in dense supercritical fluid He. The studied temperature range is increased with respect to earlier studies by the use of intense laser pulses for the transient local heating of the helium sample. The analysis of the experimental spectra is based on two different...

Université de Fribourg

Unexpected Decoupling of Stretching and Bending Modes in Protein Gels

Gibaud, Thomas ; Zaccone, Alessio ; Gado, Emanuela Del ; Trappe, Véronique ; Schurtenberger, Peter

In: Physical Review Letters, 2013, vol. 110, no. 5, p. 058303

We show that gels formed by arrested spinodal decomposition of protein solutions exhibit elastic properties in two distinct frequency domains, both elastic moduli exhibiting a remarkably strong dependence on volume fraction. Considering the large difference between the protein size and the characteristic length of the network we model the gels as porous media and show that the high and low...

Université de Fribourg

Teilhabe und Ordnung: Zur Politisierung der Weimarer Gesellschaft

Siegfried Weichlein, Université de Fribourg

In: Zur Genealogied es politischen Raums; VS Verlag für sozialwissenschaften, 2006, p. 53-76

Université de Fribourg

Mass transport properties of the tetrahydronaphthalene/n-dodecane mixture measured by investigating non-equilibrium fluctuations

Croccolo, Fabrizio ; Scheffold, Frank ; Bataller, Henri

In: Comptes Rendus Mécanique, 2013, vol. 341, no. 4–5, p. 378–385

We present preliminary near-field light scattering (NFS) data concerning the analysis of the static power spectrum and of the relaxation time constant as a function of the wave vector for non-equilibrium fluctuations (NEFs). The goal of these measurements is to obtain information about the Soret and the mass diffusion coefficients of a binary mixture undergoing thermodiffusion. In particular, we...

Université de Fribourg

Potential theory for directed networks

Zhang, Qian-Ming ; Lü, Linyuan ; Wang, Wen-Qiang ; Zhu, Yu-Xiao ; Zhou, Tao

In: PLoS ONE, 2013, vol. 8, no. 2, p. e55437

Uncovering factors underlying the network formation is a long-standing challenge for data mining and network analysis. In particular, the microscopic organizing principles of directed networks are less understood than those of undirected networks. This article proposes a hypothesis named potential theory, which assumes that every directed link corresponds to a decrease of a unit potential and...

Université de Fribourg

Does Bilateral Trust Affect International Movement of Goods and Labor?

Spring, Eva ; Grossmann, Volker

(Working Papers SES ; 442)

Trust in the citizens of a potential partner country may affect the decision to trade with or to migrate to a foreign country. This paper employs panel data to examine the causal impact of such bilateral trust on international trade and migration patterns. We apply instrumental variables (IV) approaches that capture the exogenous variance of bilateral trust separately with eight indicators of...

Université de Fribourg

The influence of constrictivity on the effective transport properties of porous layers in electrolysis and fuel cells

Holzer, L. ; Wiedenmann, Daniel ; Münch, B. ; Keller, L. ; Prestat, M. ; Gasser, Ph. ; Robertson, I. ; Grobéty, Bernard

In: Journal of Materials Science, 2013, vol. 48, no. 7, p. 2934-2952

The aim of the present investigation is to define microstructure parameters, which control the effective transport properties in porous materials for energy technology. Recent improvements in 3D-imaging (FIB-nanotomography, synchrotron X-ray tomography) and image analysis (skeletonization and graph analysis, transport simulations) open new possibilities for the study of microstructure effects. In...