Filtern
Erscheinungsjahr
Dokumenttyp
- Wissenschaftlicher Artikel (1082) (entfernen)
Sprache
- Deutsch (869)
- Englisch (210)
- Französisch (2)
- Spanisch (1)
Schlagworte
- Geldpolitik (6)
- Arbeitsrecht (4)
- Building Information Modeling (4)
- Deutschland (4)
- Energiepolitik (4)
- Kühllastberechnung (4)
- E-Learning (3)
- Europäische Union (3)
- Europäische Zentralbank (3)
- GmbH (3)
Institut
- Wirtschaftsrecht (447)
- Institut für Internetsicherheit (160)
- Wirtschaft und Informationstechnik Bocholt (68)
- Institut für Innovationsforschung und -management (55)
- Westfälisches Institut für Gesundheit (47)
- Westfälisches Energieinstitut (39)
- Wirtschaft Gelsenkirchen (36)
- Elektrotechnik und angewandte Naturwissenschaften (33)
- Informatik und Kommunikation (32)
- Wirtschaftsingenieurwesen (25)
Efficient tool to calculate two-dimensional optical spectra for photoactive molecular complexes
(2015)
In the polymer electrolyte membrane fuel cells (PEMFC) state of the art, rare and expensive platinum group metals (PGM) or PGM alloys are used as catalyst material. Reduction of PGMs in PEMFC electrodes is strongly required to reach cost targets for this technology. An optimal catalyst utilization is achieved in case of nano-structured particles supported on carbon material with a large specific surface area. In this study, graphitic material, in form of carbon nanofibers (CNF), is decorated with Pt particles, serving as catalyst material for PEMFC electrodes with low Pt loading. As a novelty, the effect of oxygen plasma treatment of CNFs previously to platinum particle deposition has been studied. Electrodes are investigated in respect of the optimal morphology, microstructure as well as electrochemical properties. Therefore, samples are characterized by means of scanning electron microscopy combined with energy dispersive X-ray analysis, transmission electron microscopy, thermogravimetry, X-ray diffraction as well as X-ray fluorescence analysis. In order to determine the electrochemical active surface area of catalyst particles, cyclic voltammetry has been performed in 0.5 M sulphuric acid. Selected samples have been investigated in a PEMFC test bench according to their polarization behavior.
A qualitative work‐flow analysis of a neurosurgical procedure indicates that the resolution of the image used to plan the intervention is the major source of inaccuracy. Quantitative experimental measurements confirm this observation. They fail, however, to explain the relationship between the accuracy of the frame components involved in a stereotactic procedure and the overall application accuracy. This investigation shows that the novel Gaussian approach is a flexible framework for the calculation of the application accuracy of frame systems. Therefore, the Gaussian approach provides a detailed understanding of the interplay between the various factors affecting accuracy. The basic ideas and limitations of the Gaussian approach are briefly explained. The effect of fiducial marker distribution and registration is investigated and shown to introduce a spatial dependence to the accuracy. The results of the Gaussian approach are compared with experimental data for three stereotactic frame devices: Leksell G, Cosman–Roberts–Wells, and Brown–Roberts–Wells. Although the Gaussian approach is an approximation, it reproduces the accuracy measured in the experiment within the statistical error of that experiment. Comp Aid Surg 4:77–86 (1999). © 1999 Wiley‐Liss, Inc.