TY - GEN AU - Hellebrand, Sybille AU - Wunderlich, Hans-Joachim ID - 13084 KW - WORKSHOP TI - Ein Verfahren zur testfreundlichen Steuerwerkssynthese ER - TY - GEN AU - Hellebrand, Sybille AU - Paulo Teixeira, Joao AU - Wunderlich, Hans-Joachim ID - 13085 KW - WORKSHOP TI - Synthesis for Testability - the ARCHIMEDES Approach ER - TY - CONF AU - Platzner, Marco AU - Steger, Christian AU - Weiss, Reinhold ID - 13468 T2 - Proceedings of the 7th Mediterranean Electrotechnical Conference TI - Experimental Evaluation of Multi-DSP Architectures in High Performance Applications ER - TY - JOUR AU - Bechstedt, F AU - Schmidt, Wolf Gero AU - Wenzien, B ID - 13853 IS - 5 JF - Europhysics Letters (EPL) SN - 0295-5075 TI - Energetics and Structure of Ordered Sb Overlayers and Sb Clusters on GaAs(110) Probed by Ab Initio Calculations VL - 25 ER - TY - JOUR AU - Schmidt, Wolf Gero AU - Srivastava, GP ID - 13854 IS - 4 JF - Solid State Communications SN - 0038-1098 TI - First principles calculations of interface phonons of an Epitaxial Sb monolayer on GaAs(110) and InP(110) VL - 89 ER - TY - JOUR AU - Schmidt, Wolf Gero AU - Wenzien, Bernd AU - Bechstedt, Friedhelm ID - 13855 IS - Part A JF - Surface Science SN - 0039-6028 TI - Coverage-dependent bonding of Sb on GaAs (110) VL - 307-309 ER - TY - JOUR AU - Schmidt, Wolf Gero AU - Wenzien, B. AU - Bechstedt, F. ID - 13856 IS - 7 JF - Physical Review B SN - 0163-1829 TI - Chemisorption of antimony on GaAs(110) VL - 49 ER - TY - CONF AU - Sun, J. AU - Grotstollen, I. ID - 30025 T2 - Proceedings of IECON'94 - 20th Annual Conference of IEEE Industrial Electronics TI - Pulsewidth modulation based on real-time solution of algebraic harmonic elimination equations ER - TY - CONF AU - Ruff, M. AU - Bunte, A. AU - Grotstollen, H. ID - 30021 T2 - Proceedings of 1994 IEEE Industry Applications Society Annual Meeting TI - A new self-commissioning scheme for an asynchronous motor drive system ER - TY - CONF AU - Sun, J. AU - Beineke, S. AU - Grotstollen, H. ID - 30027 T2 - Proceedings of 1994 Power Electronics Specialist Conference - PESC'94 TI - DSP-based real-time harmonic elimination of PWM inverters ER - TY - CONF AU - Heinemann, L. AU - Schulze, R. AU - Wallmeier, P. AU - Grotstollen, H. ID - 30026 T2 - Proceedings of 1994 Power Electronics Specialist Conference - PESC'94 TI - Modeling of high frequency inductors ER - TY - CONF AU - Fröhleke, N. AU - Becker, B. AU - Grotstollen, H. AU - Magaritis, B. AU - Vollmer, L. ID - 30023 T2 - Proceedings of 1994 IEEE Industry Applications Society Annual Meeting TI - Analysis and design of isolated high power boost topologies and simulations with quasi-static and quasi-stationary transformer models ER - TY - CONF AU - Fröhleke, N. AU - Mende, R. AU - Grotstollen, H. AU - Margaritis, B. AU - Vollmer, L. ID - 30024 T2 - Proceedings of IECON'94 - 20th Annual Conference of IEEE Industrial Electronics TI - Isolated boost full bridge topology suitable for high power and power factor correction ER - TY - CONF AU - Fröhleke, N. AU - Becker, B. AU - Wallmeier, P. AU - Grotstollen, H. ID - 30022 T2 - Proceedings of 1994 IEEE Industry Applications Society Annual Meeting TI - Computer aided optimization of multi-winding transformers for SMPS considering HF-effects ER - TY - JOUR AB - Abstract: Historia Mathematica 22 (1995), #22.2.62 (I. Anellis). Rezensionen: Zbl. Math. 812.01012 (I. Grattan-Guinness); MR 95m:03002 (M. Guillaume). AU - Peckhaus, Volker ID - 17489 JF - Modern Logic TI - Wozu Algebra der Logik? Ernst Schröders Suche nach einer universalen Theorie der Verknüpfungen VL - 4 ER - TY - GEN AU - Peckhaus, Volker ID - 17774 T2 - Modern Logic TI - Erik Heijerman/H. Walter Schmitz (eds.), Significs, Mathematics and Semiotics. The Signific Movement in the Netherlands. Proceedings of the International Conference Bonn 19–21 November 1986. Nodus Publicationen: Münster 1991 (= Materialien zur Geschichte der Sprachwissenschaft und der Semiotik; 5) VL - 4 ER - TY - JOUR AB - (Abdruck von “Alexander Rüstow's Thesis”, Beitrag für russell-l@mcmail.cis.mcmaster am 17. Juni 1994) AU - Peckhaus, Volker ID - 17841 IS - September-Oktober 1994 JF - History of Logic Newsletter TI - Rüstow’s Thesis on Russell’s Paradox VL - 13 ER - TY - CHAP AU - Peckhaus, Volker ID - 17837 T2 - Abstract of Papers Presented to the American Mathematical Society TI - The Axiomatic Method and Ernst Schröder’s Algebraic Approach to Logic [Abstract] VL - 15, Nr. 5 (August 1994) ER - TY - CHAP AU - Peckhaus, Volker ID - 17834 T2 - Modern Logic Calendar 1994 TI - Ernst Schröder ER - TY - GEN AB - [Abdruck siehe 7.13, revidierte Fassung 4.18] AU - Peckhaus, Volker ID - 17896 TI - Alexander Rüstow's Thesis, Beitrag für russell-l@mcmail.cis.mcmaster am 17. Juni 1994 [Abdruck: Rüstow’s Thesis on Russell’s Paradox, History of Logic Newsletter, Nr. 13 (September–Oktober 1994), 2–3] [revidierte Fassung: Rüstow’s Thesis on Russell’s Paradox”, Modern Logic 5 (1995), 167–169] ER - TY - THES AU - Josef Wiesing, Josef ID - 30850 TI - Betrieb der feldorientierten geregelten Asynchronmaschine im Bereich oberhalb der Nenndrehzahl ER - TY - CONF AU - Hagengruber, Ruth Edith ED - Heinekamp, Albert ED - Hein, Isolde ID - 15509 T2 - Leibniz und Europa TI - Parallelen um den Punkt zwischen Campanella und Leibniz VL - 1 ER - TY - THES AU - Hagengruber, Ruth Edith ID - 15497 SN - 3883453331 TI - Tommaso Campanella. Eine Philosophie der Ähnlichkeit ER - TY - GEN AU - Süßmann, Johannes ED - Kerber, Harald ED - Schmieder, Arnold ID - 34939 SN - 3-499-55542-5 T2 - Spezielle Soziologien. Problemfelder, Forschungsbereiche, Anwendungsorientierungen TI - [Art.] Kunstsoziologie VL - 542 ER - TY - CONF AU - Hellebrand, Sybille AU - Wunderlich, Hans-Joachim ID - 13014 T2 - ACM/IEEE International Conference on Computer-Aided Design (ICCAD'94) TI - An Efficient Procedure for the Synthesis of Fast Self-Testable Controller Structures ER - TY - CONF AU - Hellebrand, Sybille AU - Wunderlich, Hans-Joachim ID - 13059 T2 - Tagungsband der GI/GME/ITG-Fachtagung \& Rechnergestützter Entwurf und Architektur mikroelektronischer Systeme TI - Synthese schneller selbsttestbarer Steuerwerke ER - TY - CONF AU - Hellebrand, Sybille AU - Wunderlich, Hans-Joachim ID - 13013 T2 - European Design and Test Conference (EDAC/ETC/EUROASIC) TI - Synthesis of Self-Testable Controllers ER - TY - CHAP AU - van Laak, Lothar AU - Bartels, Kathrin AU - Brenig, Claudia AU - Prudlo, Marion ID - 31094 T2 - Hölderlin-Jahrbuch 29 TI - Michael Hamburgers Übersetzungen und einige neue Tendenzen in der englisch-sprachigen Hölderlin-Rezeption ER - TY - BOOK AU - Scharlau, Ingrid ID - 29079 TI - Cartesianische Grundlagen der wissenschaftlichen Psychologie ER - TY - CHAP AU - Öhlschläger, Claudia ED - Keck, Annette ED - Schmidt, Dietmar ID - 32990 T2 - AUTO(R)EROTIK. Gegenstandslose Liebe als literarisches Projekt TI - "In den Wald gehen, tief in den Wald hinein" Autoerotische Phantasmen männlicher Autorschaft in Thomas Bernhards Holzfällen. Eine Erregung ER - TY - CHAP AU - Öhlschläger, Claudia ID - 32992 T2 - Rundbrief Frauen in der Literaturwissenschaft 43: Postfeminismus. Dez. 1994 TI - Maskerade. Bericht über das 3. Symposium des Münchener Graduiertenkollegs Geschlechterdifferenz & Literatur. Ludwig- Maximilians-Universität München (27.-29.10.1994) ER - TY - CHAP AU - Öhlschläger, Claudia AU - Schmidt, Dietmar ID - 32989 T2 - Hofmannsthal-Jahrbuch 2 TI - "Weibsfauna". Zur Koinzidenz von Tiergeschichte und Pornographie am Beispiel von Bambi und Josefine Mutzenbacher ER - TY - JOUR AU - Kratzat, Krystyna AU - Schmidt, Claudia AU - Finkelmann, Heino ID - 35384 IS - 1 JF - Journal of Colloid and Interface Science KW - Colloid and Surface Chemistry KW - Surfaces KW - Coatings and Films KW - Biomaterials KW - Electronic KW - Optical and Magnetic Materials SN - 0021-9797 TI - A Doubly Branched Nonionic Oligooxyethylene V-Amphiphile: Effect of Molecular Geometry on Liquid-Crystalline Phase Behavior, 3 VL - 163 ER - TY - JOUR AU - Grabowski, D. A. AU - Schmidt, Claudia ID - 35386 IS - 9 JF - Macromolecules KW - Materials Chemistry KW - Inorganic Chemistry KW - Polymers and Plastics KW - Organic Chemistry SN - 0024-9297 TI - Simultaneous Measurement of Shear Viscosity and Director Orientation of a Side-Chain Liquid-Crystalline Polymer by Rheo-NMR VL - 27 ER - TY - JOUR AU - Disch, Stefan AU - Schmidt, Claudia AU - Finkelmann, Heino ID - 35385 IS - 4 JF - Macromolecular Rapid Communications KW - Materials Chemistry KW - Polymers and Plastics KW - Organic Chemistry SN - 1022-1336 TI - Nematic elastomers beyond the critical point VL - 15 ER - TY - JOUR AU - Schnepp, Werner AU - Schmidt, Claudia ID - 35383 IS - 2 JF - Berichte der Bunsengesellschaft für physikalische Chemie KW - General Chemical Engineering SN - 0005-9021 TI - Conformational order of amphiphilic chain molecules in lyotropic liquid-crystalline phases VL - 98 ER - TY - BOOK ED - Tophinke, Doris ID - 18433 TI - Sprachbiographie und Sprachstörung. Fallstudien zur Textproduktion bei hirnorganischen Erkrankungen ER - TY - CHAP AU - Hagengruber, Ruth Edith ED - Gómez Pin, Victor ID - 15610 T2 - Actas del primer Congreso Internacional de Ontología : categorías e inteligibilidad global : el proyecto ontológico a través de la reflexión contemporánea TI - Die Theorie des Punktes aus der Philosophie der Ähnlichkeit bei Tommaso Campanella ER - TY - CHAP AU - Hagengruber, Ruth Edith ED - Fritscher, Bernhard ED - Brey, Gerhard ID - 15608 T2 - Cosmographica et Geographica. Algorismus. Studien zur Geschichte der Mathematik und der Naturwissenschaften TI - Platons "Timaios", eine Anleitung zur wissenschaftlichen Hypothesenbildung? VL - 13 ER - TY - JOUR AU - Kamp, Hermann ID - 36179 JF - Historische Zeitschrift TI - Konflikte im hohen Norden. Ein Blick auf einige Neuerscheinungen zur isländischen und norwegischen Geschichte im Mittelalter VL - 230 ER - TY - BOOK AU - Bigga, Regine AU - Braun, F. AU - Hoffmann, L. ID - 27958 TI - Die Gleichstellung der Geschlechter im Lehrplan. Anregungen für Schule und Unterricht. ER - TY - BOOK AU - Tornieporth, G. AU - Bigga, Regine ID - 27961 TI - Erwerbsarbeit - Hausarbeit. Strukturwandel der Arbeit als Herausforderung an das Lernfeld Arbeitslehre ER - TY - CHAP AU - Bigga, Regine ED - Tornieporth, Gerda ED - Bigga, Regine ID - 37582 T2 - Erwerbsarbeit - Hausarbeit. Strukturwandel der Arbeit als Herausforderung an das Lernfeld der Arbeitslehre TI - Ergebnisse aus dem Projekt Mädchen & junge Frauen in der Arbeitswelt ER - TY - CONF AU - Felser, W. AU - Müller, Wolfgang ID - 39557 TI - EXPRESS-P - Eine Erweiterung von ISO 10303-11 zur Prozessmodellierung ER - TY - CONF AB - In this paper we present a novel approach to the layout problem of dimensional graph based dia grams We introduce a framework for e ciently solving constrained layout problems encompassing geometrical and graph based algorithms especially dedicated to the generation of diagrams These concepts as well as the aesthetics for the read ability of diagrams are presented by introducing FADE FADE is a user parametrizable frame work for the generation of EXPRESS G diagrams Our present implementation is discussed consider ing extensions to other classes of graphs and layout problems Additionally competitive approaches in this domain and their limitations are critically reviewed. AU - Eikerling, Josef AU - Müller, Wolfgang ID - 39560 T2 - Proceedings of the 17th Annual Computer Science Conference TI - FADE: A Layout Facility for Graph-Based Diagrams ER - TY - CONF AU - Hyhuis, D. AU - Müller, Wolfgang ID - 39565 T2 - Proceedings of the 2nd International Conference on Concurrent Engineering & Electronic Design Automation (CEEDA94) TI - Implementing Simultaneous Design: A Case Study ER - TY - CONF AU - Müller, Wolfgang AU - Lehrenfeld, Georg AU - Wiechers, N. ID - 39577 TI - Implementierung eines parallelen Validierungswerkzeugs für STEP-Produktdaten unter PVM ER - TY - CONF AU - Börger, Egon AU - Glässer, Uwe AU - Müller, Wolfgang ID - 39575 T2 - Proceedings of EURO-DAC'94/EURO-VHDL'94 TI - The Semantics of Behavioral VHDL'93 Descriptions ER - TY - JOUR AU - Behrens, Ulrike AU - Kitzerow, Heinz-Siegfried AU - Chilaya, Gouram ID - 40006 IS - 4 JF - Liquid Crystals KW - Condensed Matter Physics KW - General Materials Science KW - General Chemistry SN - 0267-8292 TI - Electro-optic effect in polymer-dispersed cholesteric liquid crystals with medium chirality VL - 17 ER - TY - GEN AU - Grotjahn, Rebecca ED - Böttcher, Dirk ED - Guratzsch, Herwig ED - Mlynek, Klaus ID - 37871 SN - 978-3934920538 T2 - Hannover Kunst- und Kultur­lexikon TI - Stadtgeschichte in Daten – Musik ER - TY - CONF AU - Lehrenfeld, Georg AU - Müller, Wolfgang AU - Wiechers, N. ID - 39554 TI - Ein paralleles Framework fuer die Validierung von STEP-Produktdaten ER - TY - CONF AU - Lehrenfeld, Georg AU - Müller, Wolfgang AU - Wiechers, N. ID - 39566 T2 - Proceedings of the 2nd International Conference on Concurrent Engineering & Electronic Design Automation (CEEDA94) TI - Parallel Validation of STEP Files ER - TY - CONF AU - Lehrenfeld, Georg AU - Müller, Wolfgang ID - 39569 TI - Computational Model of a Logical Visual Programming Language ER - TY - CONF AB - The upcoming ISO standard EXPRESS has been de- #ned as a data speci#cation language for the use within STEP. EXPRESS supports the modeling of static structural relationships and consistency constraints whereas the applicability of EXPRESS for the modeling of behavior is very limited. Thus, at present there is an ongoing discussion by which means EXPRESS should be extended with. AU - Felser, Winfried AU - Müller, Wolfgang ID - 39572 T2 - Proceedings of the 1994 ASME Computers in Engineering Conference TI - EXPRESS-P - Extending EXPRESS for Process Modeling and Monitoring ER - TY - JOUR AU - REHAGE, M AU - Noé, Reinhold ID - 38463 IS - 14 JF - ELECTRONICS LETTERS SN - 0013-5194 TI - WAVELENGTH-SELECTIVE POLARIZATION ANALYZER WITH INTEGRATED TI LINBO3 ACOUSTOOPTICAL TE-TM CONVERTER VL - 30 ER - TY - JOUR AU - Molsen, Henning AU - Kitzerow, Heinz-Siegfried ID - 40322 IS - 2 JF - Journal of Applied Physics KW - General Physics and Astronomy SN - 0021-8979 TI - Bistability in polymer‐dispersed ferroelectric liquid crystals VL - 75 ER - TY - CONF AU - Crooker, Peter P. AU - Kitzerow, Heinz-Siegfried AU - Xu, F. ED - Shashidhar, Ranganathan ID - 40316 SN - 0277-786X T2 - Liquid Crystal Materials, Devices, and Applications III TI - Polymer-dispersed cholesteric liquid crystals ER - TY - JOUR AU - Kitzerow, Heinz-Siegfried ID - 40325 IS - 1 JF - Liquid Crystals KW - Condensed Matter Physics KW - General Materials Science KW - General Chemistry SN - 0267-8292 TI - Polymer-dispersed liquid crystals From the nematic curvilinear aligned phase to ferroelectric films VL - 16 ER - TY - JOUR AU - Xu, F. AU - Kitzerow, Heinz-Siegfried AU - Crooker, P. P. ID - 40323 IS - 4 JF - Physical Review E SN - 1063-651X TI - Director configurations of nematic-liquid-crystal droplets: Negative dielectric anisotropy and parallel surface anchoring VL - 49 ER - TY - JOUR AB - A novel technique to produce planar and homeotropic alignment of smectic liquid crystals is presented. The technique is based on producing an anisotropic polymer network in the bulk by photo-polymerizing a mixture of photoresist material and liquid crystal by linearly polarized UV-light. Both uniform planar alignment and homeotropic alignment can be obtained depending on the curing conditions. In the case of planar alignment, the orientation of liquid crystal molecules is governed by the direction of the polarization vector of the UV-light, thus making it possible to produce a defined azimuthal orientation of the liquid crystal director. This technique obviates the need to give any previous treatment to the bounding substrates. AU - Jain, Sukhmal C. AU - Kitzerow, Heinz-Siegfried ID - 40317 IS - 5A JF - Japanese Journal of Applied Physics KW - General Physics and Astronomy KW - General Engineering SN - 0021-4922 TI - A New Method to Align Smectic Liquid Crystals by Photo-Polymerization VL - 33 ER - TY - JOUR AU - Behrens, Ulrike AU - Kitzerow, Heinz-Siegfried ID - 40321 IS - 8 JF - Polymers for Advanced Technologies KW - Polymers and Plastics SN - 1042-7147 TI - Utility of a liquid crystalline diacrylate for bistable switching cholesteric gel displays VL - 5 ER - TY - JOUR AU - Jain, Sukhmal C. AU - Kitzerow, Heinz-Siegfried ID - 40318 IS - 22 JF - Applied Physics Letters KW - Physics and Astronomy (miscellaneous) SN - 0003-6951 TI - Bulk‐induced alignment of nematic liquid crystals by photopolymerization VL - 64 ER - TY - JOUR AU - Herzog, Bernd AU - Huber, Klaus AU - Rennie, Adrian R. ID - 42055 IS - 2 JF - Journal of Colloid and Interface Science KW - Colloid and Surface Chemistry KW - Surfaces KW - Coatings and Films KW - Biomaterials KW - Electronic KW - Optical and Magnetic Materials SN - 0021-9797 TI - Characterization of Worm-like Micelles Containing Solubilized Dye-Molecules by Light Scattering Techniques VL - 164 ER - TY - JOUR AU - Maloney, Colette AU - Huber, Klaus ID - 42054 IS - 2 JF - Journal of Colloid and Interface Science KW - Colloid and Surface Chemistry KW - Surfaces KW - Coatings and Films KW - Biomaterials KW - Electronic KW - Optical and Magnetic Materials SN - 0021-9797 TI - Mixtures of Polyacrylic Acid and Nonionic Surfactants at the Water/Air Interface VL - 164 ER - TY - CONF AU - Hilleringmann, Ulrich AU - Adams, S. AU - Goser, K. ID - 39908 T2 - ESSDERC ’94: 24th European Solid State Device Research Conference TI - Micromechanic Pressure Sensors with Optical Readout and CMOS-Amplifiers on Silicon ER - TY - JOUR AU - Schroeter-Wittke, Harald ID - 43511 JF - Der Evangelische Erzieher TI - Zwischen Fest und Alltag. Symboldidaktische Anmerkungen zur Gestaltung christlicher Religion in der Primarstufe VL - 46 ER - TY - CHAP AU - Schroeter-Wittke, Harald ED - Domay, Erhard ID - 43514 T2 - Gottesdienstpraxis. Serie A. IV. Perikopenreihe Band 2 TI - 4. Sonntag nach Trinitatis. Predigttext: 1. Petrus 3,8-15a(15b-17) ER - TY - JOUR AU - Schroeter-Wittke, Harald ID - 43513 JF - Der Evangelische Erzieher TI - In Bibel steckt Musik. Eine Er-Hörung von 1 Kön 19 VL - 46 ER - TY - GEN AU - Schroeter-Wittke, Harald ID - 43515 T2 - Der Evangelische Erzieher TI - Ingrid Schoberth: Erinnerung als Praxis des Glaubens VL - 46 ER - TY - JOUR AU - Schroeter-Wittke, Harald ID - 43512 JF - Der Evangelische Erzieher TI - Friedhof der Vergessenen VL - 46 ER - TY - JOUR AB - We study the critical field for the formation of Wannier-Stark ladders and Bloch oscillations in GaAs/AlxGa1−xAs superlattices at low temperatures. From the results of photocurrent and transient four-wave mixing experiments, we conclude that the critical field is higher for superlattices with wide minibands than for superlattices, with narrow minibands. The explanation for this dependence is that intraminiband scattering due to LO-phonon emission is excluded in minibands narrower than the LO-phonon energy. AU - Meier, Torsten AU - von Plessen, G. AU - Feldmann, J. AU - Göbel, E.O. AU - Thomas, P. AU - Goosen, K.W. AU - Kuo, J.M. AU - Kopf, R.F. ID - 43593 IS - 19 JF - Physical Review B TI - Influence of scattering on the formation of Wannier-Stark ladders and Bloch oscillations in semiconductor superlattices VL - 49 ER - TY - JOUR AB - We present a microscopic analysis of coherent effects induced by electric fields in photoexcited semiconductors in the presence of the Coulomb interaction. Both the terahertz emission and four-wave-mixing signals arising from Bloch oscillations in a semiconductor superlattice are computed consistently. It is predicted that Bloch oscillations should be observable also for miniband widths on the order of the exciton binding energy. AU - Meier, Torsten AU - von Plessen, G. AU - Thomas, P. AU - Koch, S.W. ID - 43592 IS - 6 JF - Physical Review Letters TI - Coherent electric-field effects in semiconductors VL - 73 ER - TY - CONF AB - The coherent dynamics of exciton wavepackets in (GaIn)As/GaAs as well as (GaIn)As/Ga(PAs) multiple quantum well structures is studied by means of transient four-wave mixing (FWM) experiments. The wavepackets are generated by simultaneous excitation of several exciton transitions with laser pulses of about 100 fs duration. The time-integrated FWM signals exhibit a pronounced modulation superimposed on the overall decay which can be attributed to the quantum interference of the different eigenstates. In the time-resolved FWM signals this interference is not present, reflecting the interplay between many-body Coulomb effects and inhomogeneous broadening. This experimental technique is then employed to extract the exciton binding energies in pseudomorphic symmetrically strained (GaIn)As/GaIPAs) with various In contents. AU - Meier, Torsten AU - Koch, M. AU - Feldmann, J. AU - Göbel, E.O. AU - Jahnke, F. AU - Schäfer, W. AU - Thomas, P. AU - Koch, S.W. AU - Nickel, H. AU - Luttgen, S. AU - Stolz, W. ID - 43450 IS - 11S T2 - Proceedings der 8. International Winterschool on New Developments in Physics TI - Coherent Dynamics of Exciton Wavepackets in Semiconductor Heterostructures VL - 9 ER - TY - CHAP AB - Since the realization of semiconductor heterostructures vertical transport of electrically injected carriers has been one of the most interesting topics in semiconductor physics. Precise engineering of semiconductor layers and thus electronic energy levels allows the tailoring of transport properties over a wide range and has even led to the invention of semiconductor devices relying on ballistic electron transport. In addition, negative differential resistance (NDR) can be realized by using tunneling diodes containing double-barrier heterostructures or a superlattice structure.5,6 Actually, the proposal of Esaki and Tsu5 to use electronic Bloch oscillations in the miniband of a semiconductor superlattice to realize NDR marked the starting point for the physics and applications of semiconductor heterostructures. AU - Meier, Torsten AU - Feldmann, J. AU - von Plessen, G. AU - Thomas, P. AU - Göbel, E.O. AU - Goosen, K.W. AU - Miller, D.A.B. AU - Cunningham, J.E. ED - Phillips, R.T. ID - 43598 SN - 978-1-4757-9750-3 T2 - Coherent Optical Interactions in Semiconductors TI - Vertical transport studied by sub-picosecond four-wave mixing experiments ER - TY - CHAP AB - Transient four-wave mixing (TFWM) experiments have been widely used to study the excitation dynamics of excitons in quantum wells [1]. Recently is has been observed that TFWM signals, especially quantum beats between heavy-hole (hh) and light-hole (lh) excitons, strongly depend on the polarization of the incident laser pulses [2–6]. This dependence is presently being investigated. AU - Meier, Torsten AU - Bennhardt, D. AU - Thomas, P. AU - Hu, Y.Z. AU - Binder, R. AU - Koch, S.W. ED - Phillips, R.T. ID - 43597 T2 - Coherent Optical Interactions in Semiconductors TI - Theory of polarization-dependent four-wave mixing using the optical Bloch equations ER - TY - JOUR AB - A three-pulse degenerate four-wave-mixing experiment and its theoretical analysis reveal contributions of local field and biexciton effects to the nonlinear optical response of the two-dimensional exciton. Quantum beats with a frequency equivalent to the biexciton binding energy appear only for specific polarizations. Polarization-dependent spectrally resolved four-wave mixing shows an additional peak that is separated from the 1s heavy-hole exciton line by the biexciton binding energy. These experimental results are in good agreement with the optical selection rules of the theoretical model, providing evidence for biexcitonic contributions to the four-wave mixing. AU - Meier, Torsten AU - Mayer, E.J. AU - Heuckeroth, V. AU - Smith, G.O. AU - Kuhl, J. AU - Bott, K. AU - Schulze, A. AU - Bennhardt, D. AU - Koch, S.W. AU - Thomas, P. AU - Hey, R. AU - Ploog, K. ID - 43595 IS - 19 JF - Physical Review B TI - Evidence of Biexcitonic Contributions to Four-wave-mixing in GaAs Quantum Wells VL - 50 ER - TY - JOUR AB - The effects of disorder and many-body interaction on the four-wave-mixing signal in semiconductor quantum wells are studied experimentally and theoretically. For weakly disordered samples it is shown that the combined influence of Coulomb and disorder effects leads to a characteristic photon-echo signal in time-resolved measurements and to oscillations in the time-integrated signal. Convincing agreement between experiment and theory is demonstrated. AU - Meier, Torsten AU - Jahnke, F. AU - Koch, M. AU - Feldmann, J. AU - Schäfer, W. AU - Thomas, P. AU - Koch, S.W. AU - Göbel, E.O. AU - Nickel, H. ID - 43594 IS - 11 JF - Physical Review B TI - Simultaneous influence of disorder and Coulomb interaction on photon echoes in semiconductors VL - 50 ER - TY - JOUR AU - Meier, Torsten AU - von Plessen, G. AU - Feldmann, J. AU - Thomas, P. AU - Göbel, E.O. AU - Koch, S.W. ID - 43596 IS - 12 JF - Optics and Photonics News TI - Intrinsic perturbations of Bloch oscillations and Wannier Stark ladders in semiconductor superlattices VL - 5 ER - TY - CONF AB - The strong influence of exciton/exciton interaction on the nonlinear optical response of the 2D exciton in GaAs quantum wells has been demonstrated in several recent experimental studies. The theoretical model for the microscopic coupling mechanism is still the subject of controversy, however. In ref. [1], we have presented a model including a density dependent coupling between opposite spin excitons which assumes that the interaction results in a renormalization of the matrix elements, dephasing rates and energies of the transition from the single-exciton state to the two-exciton state with respect to the corresponding quantities for the single exciton transitions. In contrast, Wang et al. claim that all experimental observations are explained by a density induced dephasing rate and that biexciton states play no role [2]. Here we present a new 3-pulse degenerate-four-wave-mixing (DFWM) configuration which is able to differentiate between pure local field effects and biexcitonic contributions to the time-integrated signal. Experiments were performed on an almost homogeneously broadened GaAs/Al0.3Ga0.7As single QW (well width 20 nm, photoluminescence line 0.3 meV, homogenous linewidth 0.15 meV) in the backward reflection geometry. The sample was cooled to 10 K and excited by a sequence of three pulses (1.1 ps duration) with equal intensity, wave vectors 𝑘→1,𝑘→2,𝑘→3 and delays τ12 and τ13 between the second and first and the third and first pulse, respectively. The signal was monitored in the direction 𝑘→𝑠=𝑘→1+𝑘→2−𝑘→3 which provides no signal for the chosen pulse length if local field and renormalization effects are negligible. The peak intensity of the time-integrated DFWM signal has been calculated by solving the optical Bloch for a system of two non-interacting two-level systems (2LS) with opposite circular polarization selection rules (local field effect) and for the renormalized four-level system (4LS) depicted in Fig. 1 which assumes the formation of biexcitons between excitons with opposite spins. The signal strength is proportional to the strength of the local field in the case of the 2LS and to the renormalization for the 4LS. The peak signal intensities expected for pure local field and pure biexction contributions are summarized in the second and third column of Table 1 for eight experimental configurations applying different linear and circularly polarized pulses. The values are normalized to the signal strength predicted for three parallel linearly polarized pulses. Close inspection of the data reveals remarkable differences of the peak amplitude with polarization geometry for the two coupling models. AU - Meier, Torsten AU - Kuhl, J. AU - Mayer, E.J. AU - Smith, G.O. AU - Bennhardt, D. AU - Schulze, A. AU - Thomas, P. AU - Hey, R. AU - Ploog, K. ID - 44283 T2 - International Conference on Ultrafast Phenomena TI - Contributions of Bound and Unbound Two-Exciton States to the Nonlinear Optical Response of GaAs Quantum Wells ER - TY - CONF AB - Several recent experimental and theoretical studies have demonstrated the importance of exciton/exciton coupling due to Coulomb interactions for the nonlinear optical response of the 2D exciton in GaAs quantum wells (QWs).1,2 These results imply that multilevel models are required in order to provide a theoretically appropriate description of the nonlinear behavior. Previous application of a renormalized 9-level system has proven successful in describing the third-order response of hh-excitons in GaAs quantum wells.2 We present a comprehensive experimental and theoretical investigation of the polarization selection rules for degenerate- four-wave-mixing (DFWM) and quantum beating of hh and lh transitions in a GaAs QW. Depending on the polarization and temporal sequence of the three pulses simultaneous excitation of the hh and lh transitions generates either quantum beats (QB), no modulation of the signal, or a superposition of QB and polarization interference (PI) effects as proved by spectrally resolved (SR)-DFWM. AU - Meier, Torsten AU - Mayer, E.J. AU - Smith, G.O. AU - Kuhl, J. AU - Schulze, A. AU - Bennhardt, D. AU - Koch, S.W. AU - Thomas, P. AU - Hey, R. AU - Ploog, K. ID - 44284 T2 - Proceedings of the 5th European Quantum Electronics Conference TI - Polarization selection rules for quantum beating between light and heavy holes in GaAs quantum wells ER - TY - CONF AB - Although the importance of exciton/exciton interactions for the nonlinear optical response of GaAs quantum wells (QW) is well established by many experimental observations, the role of biexciton states in these processes is still an open question, even at low excitation densities. Evidence for the formation of biexcitons has been independently derived from pump-probe studies [1], from the density dependence of the photoluminescence (PL) line shape [2] and from signal modulations observed in degenerate-four-wave-mixing (DFWM) with incoherent light pulses [3]. Here, we report on time-resolved DFWM with parallel (PP) and cross-polarized (CP) pulses. Depending on the polarization geometry, the signals reveal strong quantum beats which correspond to the splitting between either the heavy hole (hh) and light hole (lh) exciton or the hh exciton and the biexciton. AU - Meier, Torsten AU - Mayer, E.J. AU - Smith, G.O. AU - Kuhl, J. AU - Bennhardt, D. AU - Schulze, A. AU - Thomas, P. AU - Hey, R. AU - Ploog, K. ID - 44282 T2 - International Conference on Ultrafast Phenomena TI - Observation of Biexcitons in Time-Resolved Degenerate-Four-Wave-Mixing on GaAs Quantum Wells ER - TY - CONF AB - We have performed sub-picosecond four-wave mixing experiments on a series of symmetrically strained (GaIn)As/Ga(AsP) multiple quantum wells. We show that these measurements allow a precise determination of exciton binding energies. One of the advantages of this quantum beat method as compared to linear optical methods is that a determination of the exciton binding energy is possible even in the presence of considerable inhomogeneous broadening. In addition, the dependence of the exciton binding energy on the strain in the (GaIn)As quantum well layers suggests that the reduced electron-hole effective mass is not influenced by the increase in strain. AU - Meier, Torsten AU - Koch, M. AU - Stolz, W. AU - Feldmann, J. AU - Thomas, P. AU - Göbel, E.O. ID - 43600 IS - 3 T2 - Proceedings der 7. International Conference on Superlattices, Microstructures and Microdevices TI - Determination of excitonic binding energies in symmetrically strained (GaIn)As/Ga(PAs) multiple quantum wells using quantum beat spectroscopy VL - 15 ER - TY - CONF AB - In the absence of scattering mechanisms, a crystal electron subjected to a homogeneous electric field undergoes a periodic motion in both momentum and real space. This oscillatory motion is known as Bloch oscillations (BOs) and has recently been detected in transient four-wave mixing (FWM) and Tera-Hertz emission experiments on semiconductor superlattices. It is generally assumed that the minimum field required for the observation of BOs is controlled by the rate of scattering in the material. However, an experimental verification of this point is still lacking. AU - Meier, Torsten AU - von Plessen, G. AU - Feldmann, J. AU - Göbel, E.O. AU - Thomas, P. AU - Goossen, K.W. AU - Kuo, J.M. AU - Kopf, R.F. ID - 44280 SN - 1-55752-342-8 T2 - International Quantum Electronics Conference TI - Field-induced dynamics of a wave packet in a wide superlattice miniband ER - TY - CONF AB - The strong nonlinear optical response of the 2D exciton in GaAs quantum wells at relatively low excitation densities has been observed in many experimental studies in accordance with theoretical predictions. In principle, exciton/exciton interaction results in a renormalization of the transition matrix elements, dephasing rates and frequencies of the excitonic states. Wang et al.1 claimed that all experimental results can be explained by a density- induced enhanced dephasing rate. In a previous paper,2 we have suggested a density dependent coupling between opposite spin excitons, which involves all three renormalization phenomena. AU - Meier, Torsten AU - Smith, G.O. AU - Mayer, E.J. AU - Kuhl, J. AU - Schulze, A. AU - Bennhardt, D. AU - Koch, S.W. AU - Thomas, P. AU - Hey, R. AU - Ploog, K. ID - 44279 T2 - European Quantum Electronics Conference TI - Direct verification of the existence of biexcitons in GaAs qauntum wells ER - TY - CONF AB - A proper description of subpicosecond four-wave-mixing (FWM) experiments for excitonic transitions in semiconductor heterostructures must consider the fact that the spectrally broad laser pulses excite not only the 1s bound exciton state but also energetically higher bound exciton states and the lower-lying part of the unbound continuum states. In this paper, we report results of transient and time-resolved FWM-experiments in which such ’excitonic wave packets’ play a crucial role. In addition, a theoretical treatment of the problem based on the solution of the semiconductor Bloch is presented. We show that the time-dependent nonlinear response is determined by an interplay between inhomogeneous broadening and Coulomb interaction. AU - Meier, Torsten AU - Koch, M. AU - Jahnke, F. AU - Feldmann, J. AU - Schäfer, W. AU - Thomas, P. AU - Koch, S.W. AU - Göbel, E.O. AU - Nickel, H. ID - 44285 TI - Interplay Between Inhomogeneous Broadening and Coulomb Interaction in the Dynamics of Excitonic Wave Packets ER - TY - GEN AU - Tulodziecki, G. AU - Herzig, Bardo ID - 45230 TI - Hinweise zur Statistik. Arbeitspapier ER - TY - CHAP AU - Schuster, Britt-Marie ED - Brandt , Gisela ID - 31299 KW - Sprachliche Formelhaftigkeit/-Musterhaftigkeit T2 - Bausteine zu einer Geschichte des weiblichen Sprachgebrauchs. Forschungsberichte – Projektangebote – Forschungskontexte TI - Kreativität und Reproduktion. Annäherung an den Bildungshorizont von Ursula Weida ER - TY - CONF AU - Peckhaus, Volker ID - 17487 T2 - VI. Internationalen Leibniz-Kongreß. Vorträge I. Teil, Hannover, 18.–22.7.1994 TI - Leibniz als Identifikationsfigur der britischen Logiker des 19. Jahrhunderts ER - TY - JOUR AB - Abstracts: MR 94m:01033; Zbl. Math. 798.01016 (N.I. Osetinski); Philosopher’s Index 28.3 (Herbst 1994), 179. AU - Peckhaus, Volker ID - 17486 JF - History and Philosophy of Logic TI - Benno Kerry. Beiträge zu seiner Biographie VL - 15 ER - TY - CHAP AU - Hilgert, Joachim AU - Neeb, K.-H. ED - Doebner, H.D. ID - 51481 T2 - Generalized Symmetries in Physics TI - Poisson Lie Groups and Non-LInear Convexity Theorems ER - TY - CHAP AU - Hilgert, Joachim ED - Tanner, E.A. ED - Wilson, R. ID - 51482 T2 - Non-Compact Lie Groups and some of their Applcations TI - Radon Transform on Halfplanes via Group Theory VL - 249 ER - TY - CHAP AU - Hilgert, Joachim AU - Neeb, K.-H. ED - Gindikin, S.G. ED - Michor, P. ID - 51480 T2 - 75 Years of Radon Transform TI - A General Setting for Wiener-Hopf Operators ER - TY - JOUR AU - Hilgert, Joachim AU - Neeb, K.-H. AU - Orsted, B. ID - 51438 JF - J. Lie Theory TI - The Geometry of Nilpotent Coadjoint Orbits of Convex Type in Hermitian Lie Algebras VL - 4 ER - TY - JOUR AU - Hilgert, Joachim AU - Faraut, J. AU - Ólafsson, G. ID - 51439 JF - Ann. Inst. Fourier TI - Spherical Functions on Ordered Symmetric Spaces VL - 44 ER - TY - JOUR AU - Hilgert, Joachim AU - Neeb, K.-H. AU - Plank, W. ID - 51440 JF - Compositio Math. TI - Symplectic Convexity Theorems and Coadjoint Orbits VL - 94 ER - TY - JOUR AU - Hilgert, Joachim ID - 51441 JF - Canad. J. Math. TI - A Convexity Theorems for Boundaries of Ordered Symmetric Spaces VL - 46 ER - TY - GEN AU - Hilgert, Joachim ID - 51596 T2 - Zentralblatt für Math. TI - Leptin, H. und J. Ludwig. Unitary Representation Theory of Exponential Lie Groups (De Gruyter, Berlin, 1994) ER - TY - JOUR AU - Betz, Stefan ID - 2561 JF - Zeitschrift für Betriebswirtschaft TI - Die Berücksichtigung von technischem Fortschritt im Konzept der investitionstheoretisch fundierten Abschreibung VL - 65 ER - TY - JOUR AU - Betz, Stefan ID - 2563 JF - Zeitschrift für Planung TI - Die Bedeutung der Periodenplanbeschäftigung im Rahmen einer investitionstheoretisch fundierten Kostenrechnung VL - 6 ER - TY - GEN AU - Eke, Norbert Otto ID - 19555 IS - H. 2 T2 - Wirkendes Wort TI - Ingo Schmidt, Florian Vaßen. Unter Mitarbeit von Uwe Sänger sowie Roger Fornhoff, Anja Maria Prochaska und Hendrik Werner: Bibliographie Heiner Müller 1948-1992. Bielefeld 1993 VL - 45 ER -