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Contains fulltext : 33007.pdf (Publisher’s version ) (Open Access)

In this paper the influence of adsorbed hydrogen on the behavior of gold nanojunctions is investigated. It is found, that the hydrogen environment has a strong effect on the conductance of atomic-sized gold junctions, which is markedly reflected by the growth of an additional peak in the conductance histogram at 0.5 quantum unit, 2e^2/h. The statistical analysis of the conductance traces implies that the new peak arises due to the hydrogen-assisted distortion of atomic gold chains., Comment: 5 pages, 5 figures

Bulk resistivity and point contact spectra of Ni_xNb_{1-x} metallic glasses have been investigated as functions of temperature (0.3-300K) and magnetic field (0-12T). Metallic glasses in this family undergo a superconducting phase transition determined by the Nb concentration. When superconductivity was suppressed by a strong magnetic field, both the bulk sample R(T) and the point contact differential resistance curves of Ni_xNb_{1-x} showed logarithmic behavior at low energies, which is explained by a strong electron - "two level system" coupling. We studied the temperature, magnetic field and contact resistance dependence of Ni_{44}Nb_{56} point-contact spectra in the superconducting state and found telegraph-like fluctuations superimposed on superconducting characteristics. These R(V) characteristics are extremely sensitive detectors for slow relaxing "two level system" motion., Comment: 4 pages, 5 figures

Contains fulltext : 112816.pdf (Publisher’s version ) (Open Access)

Contains fulltext : 112835.pdf (Publisher’s version ) (Open Access)

An analytic solution of the current distribution in a two-dimensional electron gas (2D EG) near an abrupt variation in the conductance properties is given. This solution is shown to explain the approximate quantization of the two-terminal resistance of a 2D EG at values of h/${\mathrm{ie}}^{2}$. The difference between the two-terminal resistance and the Hall resistance is shown to be determined by an interplay of contact and 2D EG properties, and is argued to be of the order of ${10}^{\mathrm{\ensuremath{-}}6}$ times the Hall resistance or less, for Au-Ge-Ni and Sn contacts. Measurements in agreement with this prediction are presented.

Contains fulltext : 26913_softinsor.pdf (Publisher’s version ) (Open Access) While knowledge creation lies at the heart of scientific research, the role of knowledge typically remains implicit in studies of the practices and the management of that research. This paper examines which critical success factors (CSF's) define successful research. Based on Nonaka's knowledge spiral, it examines how processes of knowledge creation contribute to the existence or absence of success as indicated by these CSF's. It presents the outcomes of an in-depth exploration of the workings of the knowledge spiral in a university research institute. The research shows the outstanding but undervalued importance of socialization processes, whereas the most widely recognized tokens of success in academic research, given its focus on output, lie in externalization. It also shows that, while research success is typically defined at the interplay of the individual, group and institutional level, in the case organization none of the four knowledge creation processes (socialization, externalization, combination and internalization) appears to run smoothly at the institutional level RU,, 28 april 2005 Promotores : van Kempen, H., Nolte, R.J.M. Co-promotores : Elemans, J.A.A.W., Hendriks, P. VIII, 212 p.