174,875 research outputs found
Bibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
9. Gehrke (H. J.). Phokion. Studien zur Erfassung seiner historischen Gestalt
No full textGoukowsky Paul. 9. Gehrke (H. J.). Phokion. Studien zur Erfassung seiner historischen Gestalt. In: Revue des Études Grecques, tome 90, fascicule 428-429, Janvier-juin 1977. pp. 121-122
Highly conductive ion tracks in tetrahedral amorphous carbon by irradiation with 30 MeV C-60 projectiles
No full textElectrically conducting ion tracks are produced when high-energy heavy ions pass through a layer of tetrahedral amorphous carbon (ta-C). The tracks are embedded in the insulating ta-C matrix and have a diameter of about 8 nm. Earlier studies showed that the electrical currents through individual tracks produced with Au and U projectiles exhibit rather large track-to-track fluctuations. In striking contrast, 30 MeV C-60 cluster ions are shown to generate conducting tracks of very narrow conductivity distributions. Their current-versus-voltage curves are linear at room temperature. We also investigated ta-C films doped with B, N, Cu and Fe at a concentration of 1 or 2 at.%. In particular, Cu-and Fe-doped samples show increased ion track conductivity.DFG [Ho1125/17-1]; BMBF [05KK4MGA/9]Open-Access-Publikationsfonds 201
Wissenschaftliche Bibliographie Hilarion G. Petzold 1958 – 2014 mit Anhang von 2007 als Einführung
No full textDieses Archiv enthält die Gesamtbiliograpie der Werke des Autors bis Dez. 2013 nebst einiger Texte „Über H. G. Petzold“ und einen Anhang mit einer Einführung in die Struktur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author up to Dec. 2013 and some texts about H. G. Petzold, moreover an appendix with an introduction to the structure of the work in its epistemological structure and composition as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2014-petzold-h-g-2014-wissenschaftliche-gesamtbibliographie-1958-2014/peerReviewedpublishedVersio
Electrical conduction of ion tracks in tetrahedral amorphous carbon: temperature, field and doping dependence and comparison with matrix data
Full text linkThis paper gives an extended overview of the electrical properties of ion tracks in hydrogen-free tetrahedral amorphous carbon (ta-C) with a sp(3) bond fraction of about 80%. The films were grown by mass selected ion beam deposition of 100 eV C-12(+) ions. The ion tracks are generated by irradiation of ta-C films with uranium ions of 1 GeV kinetic energy. Along the ion path a conversion from diamondlike (sp(3)) carbon to graphite-like (sp(2)) carbon takes place. Topography and current measurements of individual ion tracks were performed by atomic force microscopy at ambient temperature. The temperature dependence of the electric conductivity was studied between 15 and 390 K by means of 0.28 mm(2) large contact pads averaging over about 10 7 tracks. For each sample and at each temperature the conductivity as a function of the applied electrical field (non-ohmic behaviour) was measured separately and the data were extrapolated to field zero. In this way, the zero-field conductivity was determined independent from the field dependence. In spite of large differences in the absolute values, the temperature dependence of the zero-field conductivities is found to be very similar in shape for all samples. The conductivities follow a T-1/4 law up to temperatures slightly below room temperature. At higher temperatures a transport mechanism based on over-barrier hopping dominates with an activation energy of about 220 meV for tracks and 260 meV for the ta-C matrix. The field dependence measurements show that the deviation of the I-V characteristics from ohmic behaviour decreases with increasing zero-field conductivity. We also tested Cu-doped ta-C samples and found that they conduct significantly better than pure ta-C. However, the doping also increases the zero-field conductivity resulting in a weaker contrast between the track and matrix. The data are interpreted within the so-called 'barrier model' where the electrons are assumed to move fairly freely in well-conducting sp(2) regions but encounter barriers in track sections consisting of more sp(3)-like bonds
Conductive tracks of 30-MeV C60 clusters in doped and undoped tetrahedral amorphous carbon
No full textIn insulating tetrahedral amorphous carbon (ta-C), the irradiation with 30-MeV C60 cluster ions leads to the formation of well conducting tracks. While electrical currents through individual tracks produced with monoatomic projectiles (e.g. Au or U) often exhibit rather large track to track fluctuations, C60 clusters are shown to generate highly conducting tracks with very narrow current distributions. Additionally, all recorded current–voltage curves show linear characteristics. These findings are attributed to the large specific energy loss dE/dx of the 30-MeV C60 clusters. We also investigated C60 tracks in ta-C films which were slightly doped with B, N or Fe during film growth. Doping apparently increases the ion track conductivity. However, at the same time the insulating characteristics of the pristine ta-C film can be reduced. The present C60 results are compared with data from earlier experiments with monoatomic heavy ion beams. The investigations were performed by means of atomic force microscopy including temperature dependent conductivity measurements of single ion tracks
Progress in Economics
No full textThe Author discusses the relevance of studying the progress made in economic research and how to assess the existence of different models
Conductivity enhancement of ion tracks in tetrahedral amorphous carbon by doping with N, B, Cu and Fe
No full textConducting ion tracks are formed when high-energy heavy ions (e.g. 1 GeV Au) pass through tetrahedral amorphous carbon (ta-C). These nanowires with a diameter of about 8 nm are embedded in the insulating ta-C matrix and of interest for various nanotechnological applications. Usually the overall conductivity of the tracks and the current/voltage characteristics (Ohmic or non-Ohmic) vary strongly from track to track, even when measured on the same sample, indicating that the track formation is neither complete nor homogeneous. To improve the track conductivity, doping of ta-C with N, B, Cu, or Fe is investigated.
Beneficial changes in track conductivity after doping compete with a conductivity increase of the surrounding matrix material. Best results are achieved by incorporation of 1 at.% Cu, while for different reasons, the improvement of the tracks remains moderate for N, B, and Fe doping. Conductivity enhancement of the tracks is assumed to develop during the ion track formation process by an increased number of localized states which contribute to the current transport
12. Gehrke (H.-J.), Stasis. Untersuchungen zu den inneren Kriegen in den griechischen Staaten des 5. und 4. Jahrhunderts v. Chr. (Vestigia, 35)
No full textWeil Raymond. 12. Gehrke (H.-J.), Stasis. Untersuchungen zu den inneren Kriegen in den griechischen Staaten des 5. und 4. Jahrhunderts v. Chr. (Vestigia, 35). In: Revue des Études Grecques, tome 99, fascicule 470-471, Janvier-juin 1986. pp. 184-185
- …
