TY - JOUR A1 - Hövel, H. A1 - Fritz, S. A1 - Hilger, A. A1 - Kreibig, U. A1 - Vollmer, Michael T1 - Width of cluster plasmon resonances: Bulk dielectric functions and chemical interface damping JF - In: Phys. Rev. B 48 (1993) 24, 18178–18188 N2 - The damping of collective electron resonances in clusters which develop into plasmon polaritons at larger sizes is investigated for free, supported, and embedded neutral metal clusters. Embedding of free 2 nm Ag clusters of 2-nm diameter into a SiO2 matrix leads to an increase of the width of the resonances by more than a factor of 3. The optical spectra are compared with the Mie theory using size-effect-modified dielectric functions of the solid state. The results corroborate the assumption that the widths of the resonances strongly depend on chemical interface effects. The results are briefly discussed with regard to limited-mean-free-path and quantum-size-effect theories and a recent approach by Persson. It is demonstrated that the widths of the spectra of supported and embedded clusters have to be interpreted with care since true intrinsic size effects of the clusters appear to be less effective than previously believed and can be obscured by the chemical interface damping. © 1993 The American Physical Society Y1 - 1993 U6 - https://doi.org/10.1103/PhysRevB.48.18178 ER - TY - JOUR A1 - Götz, T. A1 - Träger, F. A1 - Vollmer, Michael T1 - Desorption of metal atoms with laser light of different polarization JF - In: Applied physics / A 57 (1993) 1, pp 101-104 N2 - Laser-induced desorption of metal atoms from the surface of small metal particles has been investigated as a function of the shape of the particles and the polarization of the incident laser light. The particles were supported on LiF, quartz or sapphire substrates. In a first set of experiments, the shape of the particles was determined by recording optical transmission spectra with s- and p-polarized light incident under an angle of typically 40° with respect to the surface normal. The metal particles turn out to be oblate, the ratio of the axes perpendicular and parallel to the substrate surface being on the order of 0.5. This ratio decreases with increasing particle size. Also, the particles change shape if the temperature is raised. In further experiments, s- and p-polarized light has been used to stimulate desorption of atoms via surface plasmon excitation. It is found that the desorption rate markedly depends on the polarization of the light. This is explained by excitation of the collective electron oscillation along different axes of the non-spherical particles. Y1 - 1993 U6 - https://doi.org/10.1007/BF00331225 SP - 101 EP - 104 ER - TY - JOUR A1 - Hoheisel, W. A1 - Vollmer, Michael A1 - Träger, F. T1 - Desorption of metal atoms with laser light: Mechanistic studies JF - In: Physical Review / B 48 1993) 23, 17463-17476 N2 - Results on laser-induced desorption of metal atoms from small metal particles are presented. Experiments have been performed on sodium, potassium, and silver particles supported on a LiF(100) single-crystal surface under ultrahigh vacuum conditions. Measurements include the determination of the desorption rate as a function of laser wavelength, laser intensity, average particle size, and substrate temperature, the determination of the kinetic energy of the desorbed atoms, the investigation of the optical spectra of the supported metal particles, and the study of the influence of adsorbate molecules on the desorption rate. Furthermore, theoretical extinction and absorption spectra of the metal particles have been calculated with the classical electrodynamical Mie theory as a function of average particle size and excitation wavelength. Also, the radial electric field at the particle surface was computed. The results of the experiments and theoretical calculations are combined to give a consistent picture of the mechanism of metal-atom desorption by electronic excitation with laser light. A realistic surface potential from which the atoms escape and nonlocal optical effects are taken into account. The latter introduce additional absorption channels by the formation of electron-hole pairs in the surface layer of the particle which relax into antibonding states before desorption occurs. Finally, the mechanism is discussed in the light of similar phenomena observed for thin metal films. Possibilities for future work are outlined. © 1993 The American Physical Society Y1 - 1993 U6 - https://doi.org/10.1103/PhysRevB.48.17463 ER - TY - JOUR A1 - Götz, T. A1 - Hoheisel, W. A1 - Träger, F. A1 - Vollmer, Michael T1 - Interplay between collective and single electron excitations in large metal clusters JF - In: Zeitschrift für Physik / D 26 (1993), 267-269 Y1 - 1993 ER - TY - JOUR A1 - Hoheisel, W. A1 - Vollmer, Michael A1 - Träger, F. T1 - Laserdesorption von Metallatomen JF - In: Physikalische Blätter 49 (1993) 9, 795 - 799 N2 - Beleuchtet man die Oberfläche eines Festkörpers mit Laserlicht, können darauf adsorbierte Atome oder Moleküle abgelöst werden. Solche Desorptionsprozesse sind in jüngster Zeit in zahlreichen Experimenten untersucht worden, wobei sich das Interesse sowohl auf die Erforschung der zugrundeliegenden Mechanismen als auch auf mögliche Anwendungen dieser Reaktionen, zum Beispiel zur gezielten Modifizierung von Oberflächen, konzentriert. Besonders interessant ist das laserinduzierte Aufbrechen von Bindungen zur Oberfläche dann, wenn es nicht einfach als thermischer Prozeß durch eine Temperaturerhöhung hervorgerufen wird, sondern direkt auf einer elektronischen Anregung beruht. Solche nichtthermischen Prozesse werden selbst für Metalle beobachtet, obwohl die Kopplung der elektronischen Anregung an das Substrat hier besonders schnell abläuft. Der zugrundeliegende Mechanismus beruht auf dem Zusammenspiel einer kollektiven Elektronenoszillation und einer lokalisierten Einzelelektronenanregung, wobei auch nichtlokale optische Effekte in der Metalloberfläche eine wichtige Rolle spielen. Y1 - 1993 U6 - https://doi.org/10.1002/phbl.19930490909 ER - TY - CHAP A1 - Edel, Karl-Otto T1 - Fracture Mechanics Analysis of the Residual Service Life of the Welded Main Girders of the Highway Bridges of Ruedersdorf T2 - In: Fatigue design : papers presented at the International Symposium on Fatigue Design / organized and sponsored by VTT (Technical Research Centre of Finland) and held in Helsinki, Finland. Co-sponsored by the European Structural Integrity Society (ESIS) and the Technology Development Centre of Finland (TEKES). Ed. by J Solin ... - London : Mechanical Engineering Publ., 1993. - (ESIS publication // European Structural Integrity Society, ISSN 1566-1369 ; 16). - ISBN 0-85298-884-2 Y1 - 1993 SP - 109 EP - 120 ER - TY - JOUR A1 - Herrman, K. H. A1 - Auth, J. A1 - Möllmann, Klaus Peter A1 - Tomm, J. W. A1 - Bottner, H. A1 - Lambrecht, A. A1 - Tacke, M. A1 - Kolesnikov, V. A1 - Yunovich, A. E. A1 - Fedorenko, A. I. A1 - Mironov, O. A. A1 - Sipatov, A. Yu T1 - Band offsets in Eu-containing lead chalcogenides and lead chalcogenide superlattices from spectroscopic data JF - In: Semiconductor Science and Technology Vol. 8 (1993) 1S, pp S176-S179 N2 - The results of an experimental study of the optical and photoelectrical properties of Eu-containing lead chalcogenides and superlattices are presented. From both sets of experiments band offset data for the lead chalcogenide-europium chalcogenide heterojunction are derived. The results are compared with the data obtained from a linear interpolation of the band structures between those of the binaries. Y1 - 1993 U6 - https://doi.org/10.1088/0268-1242/8/1S/040 SN - 1361-6641 SP - S176 EP - S179 ER - TY - CHAP A1 - Edel, Karl-Otto T1 - Mit Rissen leben? : Zur Betriebssicherheit rissgeschädigter Bauteile; ein Vortrag, gehalten am 14. April 1993 in der FH Brandenburg T3 - Hochschulreihe / FH Brandenburg - 93,1 KW - Bauwerk KW - Riss KW - Betriebssicherheit Y1 - 1993 PB - Fachhochsch. Presse- und Öffentlichtkeitsarbeit CY - Brandenburg ER - TY - JOUR A1 - Edel, Karl-Otto T1 - Bruchmechanische Analyse und Bewertung der Rißausbreitung im Radkranz von Eisenbahnvollrädern. Teil 1 JF - In: Zeitschrift für Eisenbahnwesen und Verkehrstechnik : ZEV + DET 117 (1993) 8, 262-268 Y1 - 1993 SN - 0373-322X - 0941-0589 SP - 262 EP - 268 ER - TY - JOUR A1 - Edel, Karl-Otto T1 - Bruchmechanische Analyse und Bewertung der Rißausbreitung im Radkranz von Eisenbahnvollrädern. Teil 2 JF - In: Zeitschrift für Eisenbahnwesen und Verkehrstechnik : ZEV + DET 117 (1993) 9, 308-315 Y1 - 1993 SN - 0373-322X - 0941-0589 SP - 308 EP - 315 ER - TY - CHAP A1 - Brasche, Ulrich T1 - Sind Produktinnovationen mit mehrheitlich älteren Arbeitnehmern möglich? T2 - In: Alter und Erwerbsarbeit der Zukunft : Arbeit und Technik bei veränderten Alters- und Belegschaftsstrukturen; Kongreß vom 3. und 4. November 1992 in Berlin / [hrsg. für die Deutsche Forschungsanstalt für Luft- und Raumfahrt, Projektträger "Arbeit und Technik"]. H.-J. Bullinger ... (Hrsg.). - Berlin [u.a.] : Springer, 1993. - ISBN 3-540-56836-0 Y1 - 1993 SP - 150 EP - 155 ER - TY - JOUR A1 - Socolowsky, Jürgen T1 - The solvability of a free boundary problem for the stationary Navier-Stokes equations with a dynamic contact line JF - In: Nonlinear Analysis: Theory, Methods & Applications 21 (1993) 10, 763–784 Y1 - 1993 SP - 763 EP - 784 ER - TY - RPRT A1 - Barthel, S. A1 - Kindsmüller, Martin Christof A1 - Schmid, U. A1 - Schönig, S. T1 - Das FlieWaTau-DB - Ein Expertensystem zur Unterstützung von Wohnraumtausch mit Kopplung an ein Datenbanksystem BT - Projektabschlussbericht Y1 - 1993 N1 - Projektabschlussbericht. TU Berlin, Fachbereich Informatik ER - TY - GEN A1 - Kindsmüller, Martin Christof T1 - Testing the limits of LCSI MicroWorlds Logo 1.00: Developing an electronic book about the solar system Y1 - 1993 N1 - Talk and Demonstration given at the Research Seminar of the Learning and Common Sense Group, MIT Media-Lab, Cambridge, MA (USA) 28.10.93 ER - TY - CHAP A1 - Schneider, J. M. A1 - Preuss, Thomas A1 - Nielsen, P. S. T1 - Management of virtual private networks for integrated broadband communication T2 - SIGCOMM '93 : Conference proceedings ; communications, architectures, protocols and applications, September 13 - 17, 1993, San Francisco, California, USA Y1 - 1993 SN - 0-89791-619-0 U6 - https://doi.org/10.1145/166237.166259 SP - 224 EP - 237 PB - ACM CY - New York ER - TY - JOUR A1 - Stumpf, H. A1 - Fauser, B. A1 - Pfister, Winfried T1 - Composite Particle Theory in Quantum Electrodynamics JF - Zeitschrift für Naturforschung / A Y1 - 1993 SN - 1865-7109 (online) SN - 0932-0784 (print) VL - 48 IS - 7 SP - 765 EP - 776 ER - TY - JOUR A1 - Pfister, Winfried T1 - On the theory of composite gauge bosons: Calculation of coupling constants and covariant derivatives JF - Il nuovo cimento / A Y1 - 1993 U6 - https://doi.org/10.1007/BF02771452 SN - 1826-9869 (online) SN - 0369-3546 (print) VL - 106 IS - 3 SP - 363 EP - 377 ER - TY - JOUR A1 - Bunikowski, R. A1 - Fitzek, Clemens A1 - Trautmann, M. T1 - Epidemiologic and clinical aspects of HIV infection in homosexual patients and intravenous drug addicts in a comparative study JF - Gesundheitswesen Y1 - 1993 SN - 0941-3790 (Print) N1 - [Article in German] VL - 55 IS - 1 SP - 28 EP - 32 ER - TY - CHAP A1 - Mündemann, Friedhelm T1 - Fuzzy concepts for predicting the behaviour of other drivers on a highway T2 - Fuzzy Logic in Artificial Intelligence Lecture Notes in Computer Science KW - Preparation of decisions with uncertain/vague data KW - Real-time fuzzy expert systems KW - Application: autonomous mobile vehicles Y1 - 1993 U6 - https://doi.org/10.1007/3-540-56920-0_18 SP - 165 EP - 173 PB - Springer Verlag CY - Berlin Heidelberg ER - TY - BOOK A1 - Heinsohn, Jochen T1 - ALCP : ein hybrider Ansatz zur Modellierung von Unsicherheit in terminologischen Logiken T3 - Dissertationen zur künstlichen Intelligenz ; 55. KW - Terminologische Sprache KW - Unsicherheit KW - Stochastisches Modell KW - Hybride Wissensrepräsentation Y1 - 1994 SN - 3-929037-55-6 N1 - Zugl.: Saarbrücken, Univ., Diss., 1993 PB - Infix CY - Sankt Augustin ER -