Ausgewählte Publikationen

Turing structures in networks

Monday, 26th April 2010Ausgewählte Publikationen

Turing patterns in a complex network.

Researchers from the Department of Physical Chemistry of the Fritz Haber Institute of the Max Planck Society in Berlin and the Department of Physics of the Kyoto University have made an important step forward in the understanding of self-organization phenomena, extending theoretical analysis to the systems which represent complex networks. Their attention was focused on the behavior first predicted in 1952 by British mathematician Alan Turing and suggested by him to provide chemical basis for biological morphogenesis. They have reported their findings in an article appearing in Nature Physics. more

(Published online: 25 April 2010 | doi: 10.1038/NPHYS1651).

This entry is only available in English.


Increased silver activity for direct propylene epoxidation via subnanometer size effects

Monday, 19th April 2010Ausgewählte Publikationen

Results of increased silver activity for direct propylene epoxidation via subnanometer size effects have been reported in the journal Science; the work was part of a collaborative effort. Here is the abstract:

Production of the industrial chemical propylene oxide is energy-intensive and environmentally unfriendly. Catalysts based on bulk silver surfaces with direct propylene epoxidation by molecular oxygen have not resolved these problems because of substantial formation of carbon dioxide. We found that unpromoted, size-selected Ag3 clusters and ~3.5-nanometer Ag nanoparticles on alumina supports can catalyze this reaction with only a negligible amount of carbon dioxide formation an with high activity at low temperatures. Density functional calculations show that, relative to extended silver surfaces, oxidized silver trimers are more active and selective for epoxidation because of the open-shell nature of their electronic structure. The results suggest that new architectures based on ultrasmall silver particles may provide highly efficient catalysts for propylene epoxidation.

Science, vol 328 p. 224 (2010)


Eine neue Quelle für niederenergetische Elektronen

Friday, 15th January 2010Ausgewählte Publikationen

Wissenschaftler des Max-Planck-Instituts für Plasmaphysik und des Fritz-Haber-Instituts haben eine neue Quelle von langsamen Elektronen in Wasser entdeckt

Presseinformation des Fritz-Haber-Instituts 1/2010, 15. Januar 2010
Weitere Auskünfte: Melanie MuckeUwe Hergenhahn

When high-energy photons, such as X-rays, interact with an atom or molecule, energy is transferred in a process known as photoionization. This results in an ionized atom/molecule and a free electron. When embedded in condensed matter, such released electrons might undergo multiple collisions while traveling through the sample. This causes the escaping electron to lose energy. Until recently, the multiple collision effect was commonly considered the root of all low-energy electrons produced from ionizing radiation. However, researchers of the Max Planck Institute of Plasma Physics and the Fritz Haber Institute have now identified an additional source of low-energy electrons in water. The results of the Berlin team are substantial, as it is thought that DNA molecules are susceptible to damage from low-energy electrons. Their work has been published in the journal Nature Physics. [mehr (auf Englisch)]


Ein ganzes Labor auf einem Chip

Friday, 26th June 2009Ausgewählte Publikationen

Max-Planck-Forscher fangen Moleküle auf einem Mikrochip und vereinfachen damit viele Experimente drastisch

Weitere Auskünfte: Gerard Meijer, Sam Meek

Doktorand Sam Meek mit seinem Mikrochip-Abbremser.Auszug: Zu einer Zeit, in der elektronische Bauteile von nur wenigen Nanometern Größe die Regel sind, kann es auch nicht überraschen, wenn die Größe von Experimenten der physikalischen Grundlagenforschung ebenfalls schrumpft: ein gesamtes Labor findet Platz auf einem Chip. Die Pioniere dieser Entwicklung, Sam Meek und seine Kollegen vom Fritz-Haber-Institut in Berlin, entwickelten eine Mikrochipstruktur, mit der man die gleichen Experimente durchführen kann wie bisher nur mit großen Geräten. Mit Hilfe des Chips können sie Kohlenmonoxid-Moleküle in Fallen aus elektrischen Feldern kurz über der Chipoberfläche festhalten und manipulieren. Die Ergebnisse sind in Science veröffentlicht worden. [mehr]

siehe auch Presseinformation der Max-Planck-Gesellschaft

(Science, 26. Juni 2009)