@misc{9636, author = {{Tönnies, Merle}}, booktitle = {{Anglistik. International Journal of English Studies}}, number = {{1}}, pages = {{198--200}}, title = {{{Assmann, A.: Einführung in die Kulturwissenschaft}}}, volume = {{20}}, year = {{2009}}, } @misc{9727, author = {{Flotmann, Christina}}, booktitle = {{Kindlers Literaturlexikon}}, editor = {{Arnold, Heinz Ludwig}}, pages = {{409--410}}, publisher = {{J.B. Metzler Verlag}}, title = {{{Lionel Johnson}}}, volume = {{8}}, year = {{2009}}, } @inproceedings{9735, abstract = {{Die Entwicklung piezoelektrischer Tr{\"a}gheitsmotoren basiert derzeit auf Erfahrungswissen und Prototypenbau. Es existiert kein allgemeines Modell und keine Methodik f{\"u}r die systematische Entwicklung dieser Motoren. In diesem Beitrag stellen wir einen Ansatz zur Entwicklung einer solchen Methodik und den von uns aufgebauten Versuchsmotor vor. Der Motor ist modular aufgebaut; er besteht im Wesentlichen aus einer piezoelektrischen Antriebseinheit, einem Antriebsstab und dem zu bewegenden Schlitten. Eine wesentliche Aufgabe bei der modellbasierten Entwicklung von Tr{\"a}gheitsmotoren ist die hinreichende Beschreibung des dynamischen Verhaltens der Antriebseinheit. Um ein geeignetes Modell zu finden, bzw. um nachzuweisen, dass einfache parametrische Modelle gen{\"u}gen, wird die Antriebseinheit des Motors detailliert untersucht. Es zeigt sich, dass der derzeitige Aufbau eine Reihe von Nachteilen aufweist, die durch eine teilweise Neukonstruktion der Antriebseinheit beseitigt oder zumindest entsch{\"a}rft werden k{\"o}nnen.}}, author = {{Hunstig, Matthias and Hemsel, Tobias}}, booktitle = {{6. Paderborner Workshop Entwurf mechatronischer Systeme}}, editor = {{Gausemeier, Jürgen and Rammig, Franz and Schäfer, Wilhelm and Trächtler, Ansgar}}, issn = {{1948-5719}}, keywords = {{Piezoelektrischer Tr{\}}, pages = {{85--96}}, publisher = {{Heinz Nixdorf Institut, Universität Paderborn}}, title = {{{Modellbasierte Entwicklung piezoelektrischer Trägheitsmotoren}}}, volume = {{250}}, year = {{2009}}, } @inproceedings{9736, abstract = {{Self-optimizing mechatronic systems are a new class of technical systems. On the one hand, new challenges regarding dependability arise from their additional complexity and adaptivity. On the other hand, their abilities enable new concepts and methods to improve the dependability of mechatronic systems. This paper introduces a multi-level dependability concept for self-optimizing mechatronic systems and shows how planning can be used to improve the availability and reliability of systems in the operating stages.}}, author = {{Klöpper, Benjamin and Sondermann-Wölke, Christoph and Romaus, Christoph and Vöcking, Henner}}, booktitle = {{Computational Intelligence in Control and Automation, 2009. CICA 2009. IEEE Symposium on}}, keywords = {{multilevel dependability concept, probabilistic planning, self-optimizing mechatronic systems, systems reliability, mechatronics, planning (artificial intelligence), self-adjusting systems}}, pages = {{104 --111}}, title = {{{Probabilistic planning integrated in a multi-level dependability concept for mechatronic systems}}}, doi = {{10.1109/CICA.2009.4982790}}, year = {{2009}}, } @article{9738, author = {{Sattel, Thomas and Hesse, Tobias and Sondermann-Wölke, Christoph and Hüfner, Thorsten}}, journal = {{memo - mechatronik mobil}}, pages = {{30--40}}, title = {{{Potenzialfeldmethoden zur Fahrzeugführung für Fahrerassistenzsysteme zum automatisierten Fahren}}}, volume = {{1}}, year = {{2009}}, } @inproceedings{9740, abstract = {{Die Integration von Selbstoptimierung in mechatronische Systeme beinhaltet sowohl Risiken als auch Potenziale für die Verlässlichkeit. Die Risiken entstehen durch die Selbstoptimierung in den komplexen Systemen, da das Systemverhalten nur begrenzt im Voraus vorhersehbar ist. Daher wurde innerhalb des Sonderforschungsbereichs 614 ''Selbstoptimierende Systeme des Maschinenbaus" ein mehrstufiges Verlässlichkeitskonzept entworfen, welches das Ziel Verlässlichkeit stärker im Zielsystem verankert. In diesem Beitrag wird zum einen das erarbeitete Verlässlichkeitskonzept und zum anderen die Anwendung dieses Konzepts innerhalb des aktiven Spurführungsmoduls eines schienengebundenen Fahrzeugs vorgestellt. Um Programmierfehler auszuschließen wurde das Verlässlichkeitskonzept modelliert und über Model Checking verifiziert. Anhand von Simulationsergebnissen wird gezeigt, wie durch das mehrstufige Verlässlichkeitskonzept auf einen Ausfall eines Wirbelstromsensors des aktiven Spurführungsmoduls reagiert werden kann.}}, author = {{Sondermann-Wölke, Christoph and Geisler, Jens and Hirsch, Martin and Hemsel, Tobias}}, booktitle = {{Entwurf mechatronischer Systeme}}, editor = {{Gausemeier, Jürgen and Rammig, Franz Josef and Trächtler, Ansger}}, keywords = {{Verlässigkeit}}, pages = {{231 -- 242}}, title = {{{Verlässlichkeit im aktiven selbstoptimierenden Spurführungsmodul eines schienengebundenen Fahrzeugs}}}, volume = {{250}}, year = {{2009}}, } @inproceedings{9741, author = {{Sondermann-Wölke, Christoph and Hesse, Tobias and Sattel, Thomas and Hemsel, Tobias}}, booktitle = {{24. Tagung Technische Zuverlässigkeit (TTZ 2009) - Entwicklung und Betrieb zuverlässiger Produkte, Leonberg}}, pages = {{335 -- 340}}, title = {{{Menschliche Unzuverlässigkeit als Grundlage für den Entwurf von Kollisionsvermeidungssystemen.}}}, volume = {{2065}}, year = {{2009}}, } @inproceedings{9742, abstract = {{New mechatronic systems, called self-optimizing systems, are able to adapt their behavior according to environmental, user and system specific influences. Self-optimizing systems are complex and due to their non-deterministic behavior comprise hidden risks, which cannot be foreseen in the design phase of the system. Therefore, this paper presents modifications of the current condition monitoring policy, to be able to cope with this new kind of systems. Beside avoiding critical situations evoked by self-optimization, the proposed concept uses self-optimization to increase the dependability of the system. In this case, the concept is applied to the active guidance module of an innovative rail-bound vehicle.}}, author = {{Sondermann-Wölke, Christoph and Sextro, Walter}}, booktitle = {{Future Computing, Service Computation, Cognitive, Adaptive, Content, Patterns, 2009. COMPUTATIONWORLD '09. Computation World:}}, keywords = {{condition monitoring, mechatronic systems, rail bound vehicle, rail guidance module, self-optimization, self-optimizing function modules, condition monitoring, mechatronics, railway rolling stock, self-adjusting systems}}, pages = {{15 --20}}, title = {{{Towards the Integration of Condition Monitoring in Self-Optimizing Function Modules}}}, doi = {{10.1109/ComputationWorld.2009.47}}, year = {{2009}}, } @article{4152, abstract = {{A novel technique to form periodically nanostructured Si surface morphologies based on nanosphere lithography (NSL) and He ion implantation induced swelling is studied in detail. It is shown that by implantation of keV He ions through the nanometric openings of NSL masks regular arrays of hillocks and rings can be created on silicon surfaces. The shape and size of these surface features can be easily controlled by adjusting the ion dose and energy as well as the mask size. Feature heights of more than 100 nm can be obtained, while feature distances are typically 1.15 or 2 (hillock or ring) nanosphere radii, which are chosen to be between 100 and 500 nm in this study. Atomic force and scanning electron microscopy measurements of the surface morphology are supplemented by cross-sectional transmission electron microscopy, revealing the inner structure of hillocks to consist of a central cavity surrounded by a hierarchical arrangement of smaller voids. The surface morphologies developed here have the potential to be useful for fixing and separating nano-objects on a silicon surface.}}, author = {{Fischer, Frederic J.C. and Weinl, Michael and Lindner, Jörg and Stritzker, Bernd}}, issn = {{1946-4274}}, journal = {{MRS Proceedings}}, location = {{San Franicsco (USA)}}, publisher = {{Cambridge University Press (CUP)}}, title = {{{Nanoscale Surface Patterning of Silicon Using Local Swelling Induced by He Implantation through NSL-Masks}}}, doi = {{10.1557/proc-1181-dd10-02}}, volume = {{1181}}, year = {{2009}}, } @inproceedings{4180, abstract = {{We show that an optically driven carrier spin undergoes indirect dephasing even in the absence of spin-reservoir coupling and illustrate it for phonon-induced decoherence during optical spin rotation in a single quantum dot.}}, author = {{Grodecka, Anna and Machnikowski, Pawel and Förstner, Jens}}, booktitle = {{Advances in Optical Sciences Congress}}, isbn = {{9781557528735}}, keywords = {{tet_topic_qd}}, publisher = {{OSA Technical Digest (CD) (Optical Society of America, 2009)}}, title = {{{Indirect Dephasing Channel for Optically Controlled Spin in a Single Quantum Dot}}}, doi = {{10.1364/nlo.2009.nma1}}, year = {{2009}}, } @article{4182, abstract = {{We demonstrate that an optically driven spin of a carrier in a quantum dot undergoes indirect dephasing via conditional optically induced charge evolution even in the absence of any direct interaction between the spin and its environment. A generic model for the indirect dephasing with a three-component system with spin, charge, and reservoir is proposed. This indirect decoherence channel is studied for the optical spin manipulation in a quantum dot with a microscopic description of the charge-phonon interaction taking into account its non-Markovian nature.}}, author = {{Grodecka, A. and Machnikowski, P. and Förstner, Jens}}, issn = {{1050-2947}}, journal = {{Physical Review A}}, keywords = {{tet_topic_qd}}, number = {{4}}, publisher = {{American Physical Society (APS)}}, title = {{{Indirect spin dephasing via charge-state decoherence in optical control schemes in quantum dots}}}, doi = {{10.1103/physreva.79.042331}}, volume = {{79}}, year = {{2009}}, } @article{4192, abstract = {{Buried ion beam synthesized 3C-SiC layers were revealed to the surface of silicon wafers to provide lattice matched substrates for GaN thin film epitaxy. Both epitaxial SiC/Si(1 1 1) and SiC/Si(0 0 1) growth surfaces with either six- or four-fold crystal symmetry, respectively, were formed. GaN thin film growth was achieved by ion beam assisted molecular beam epitaxy (IBA–MBE) which – owing to the energy and momentum transfer of the ions – allows to deposit epitaxial thin films at particularly low growth temperatures where both the stable hexagonal and the metastable cubic polytype of GaN can be formed. It is shown by X-ray diffraction (XRD) and cross-sectional transmission electron microscopy (XTEM) that using appropriate fluxes of Ga atoms both purely hexagonal and purely cubic GaN films can be grown epitaxially on SiC/Si(1 1 1) and SiC/Si(0 0 1), respectively. Thereby Ga rich growth conditions seem to stabilize the formation of the cubic polytype. It is obvious from XTEM studies that the high density of crystal defects in the SiC layer is not transferred onto the growing GaN films and that the crystalline quality of GaN films improves with increasing film thickness. The influence of surface roughness and wettability, interfacial cavities and the nucleation of twin-type defects at the GaN/SiC interface on the crystalline quality of the GaN thin films is discussed.}}, author = {{Häberlen, M. and Gerlach, J.W. and Murphy, B. and Lindner, Jörg and Stritzker, B.}}, issn = {{0022-0248}}, journal = {{Journal of Crystal Growth}}, number = {{6}}, pages = {{762--769}}, publisher = {{Elsevier BV}}, title = {{{Structural characterization of cubic and hexagonal GaN thin films grown by IBA–MBE on SiC/Si}}}, doi = {{10.1016/j.jcrysgro.2009.12.048}}, volume = {{312}}, year = {{2009}}, } @article{4196, abstract = {{The growth of cubic group III-nitrides is a direct way to eliminate polarization effects, which inherently limit the fabrication of normally-off heterojunction field-effect transistors (HFETs) in GaN technology. HFET structures were fabricated of non-polar cubic AlGaN/GaN hetero layers grown by plasma assisted molecular beam epitaxy (MBE) on free standing 3C-SiC (001). The electrical insulation of 3C-SiC was realised by Ar+ implantation before c-AlGaN/GaN MBE. The structural properties of the epilayers were studied by highresolution x-ray diffraction (HRXRD). HFETs with normally off and normally-on characteristics were fabricated of cubic AlGaN/GaN. Capacitance-voltage (CV) characteristics of thegate contact were performed to detect the electron channel at the c-AlGaN/GaN hetero interface.}}, author = {{Tschumak, Elena and Lindner, Jörg and Bürger, M. and Lischka, K. and Nagasawa, H. and Abe, M. and As, Donald}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{1}}, pages = {{104--107}}, publisher = {{Wiley}}, title = {{{Non-polar cubic AlGaN/GaN HFETs grown by MBE on Ar+implanted 3C-SiC (001)}}}, doi = {{10.1002/pssc.200982615}}, volume = {{7}}, year = {{2009}}, } @article{4198, abstract = {{Three-dimensional (3D) photonic crystal exhibit direction-selective transmission with respect to the center frequency of the stop gap. As a model system, the stop gap of a 3D fcc inverted-opal photonic crystal is studied in the microwave regime in detail using 3D polyamide models. The difference in the direction-selective transmittance between crystals grown in two different high symmetry directions is experimentally shown and compared to numerical simulations.}}, author = {{Üpping, J. and Miclea, P.T. and Wehrspohn, R.B. and Baumgarten, T. and Greulich-Weber, Siegmund}}, issn = {{1569-4410}}, journal = {{Photonics and Nanostructures - Fundamentals and Applications}}, number = {{2}}, pages = {{102--106}}, publisher = {{Elsevier BV}}, title = {{{Direction-selective optical transmission of 3D fcc photonic crystals in the microwave regime}}}, doi = {{10.1016/j.photonics.2009.11.002}}, volume = {{8}}, year = {{2009}}, } @article{4219, abstract = {{The solar cell concept presented here is based on 3C-SiC nano- or microwires and conju¬gated polymers. Therefore the silicon carbide wires are fabricated by a sol-gel route including a car-bothermal reduction step, allowing growth with predetermined uniform diameters between 0.1 and 2μm and lengths up to several centimetres. The design of our photovoltaic device is therein based on a p-i-n structure, well known e.g. from silicon photovoltaics, involving an intrinsic semiconduc¬tor as the central photoactive layer, sandwiched between two complementary doped wide-bandgap semiconductors giving the driving force for charge separation. In our case the 3C-SiC microwires act as the electron acceptor and simultaneously as carrier material for all involved components of the photovoltaic element. }}, author = {{Greulich-Weber, Siegmund and Zöller, M. and Friedel, B.}}, issn = {{1662-9752}}, journal = {{Materials Science Forum}}, pages = {{239--242}}, publisher = {{Trans Tech Publications}}, title = {{{Textile Solar Cells Based on SiC Microwires}}}, doi = {{10.4028/www.scientific.net/msf.615-617.239}}, volume = {{615-617}}, year = {{2009}}, } @article{4220, abstract = {{We report on constructive methods providing a large range of high purity porous SiC products. All methods are based on modified sol-gel processes combined with carbothermal re¬duction. We obtain monodisperse regular pores of well defined diameters by using carbon sphere templates which are removed after SiC infiltration. A different way is a sol-gel based conversion of graphite bodies into SiC, which transfers the porosity from the graphite matrix into the final SiC product. Thus a large variety of porosity features are available, originating either from natural poro¬sity of graphite or from priorly created nano-/ microstructures in the carbonaceous base material. Whereas all our pristine porous sol-gel derived silicon carbide products are semi-insulating, doping is possible, during the growth to modifiy the electrical and optical properties. }}, author = {{Greulich-Weber, Siegmund and Friedel, B.}}, issn = {{1662-9752}}, journal = {{Materials Science Forum}}, pages = {{637--640}}, publisher = {{Trans Tech Publications}}, title = {{{Bottom-Up Routes to Porous Silicon Carbide}}}, doi = {{10.4028/www.scientific.net/msf.615-617.637}}, volume = {{615-617}}, year = {{2009}}, } @article{4221, abstract = {{Nanopatterning of silicon surfaces by means of He+ ion implantation through self-organized colloidal masks is reported for the first time. Nanosphere lithography (NSL) masks with mask openings of 46– 230 nm width were deposited on Si(100) wafers. He+ ions were implanted through these masks in order to induce a local cavity formation and Si surface swelling. The surface morphology and the subsurface structure were studied using atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (XTEM), respectively, as a function of mask and implantation parameters. It is demonstrated that regular arrays of both individual hillocks and trough-like circular rings can be generated.}}, author = {{Lindner, Jörg and Seider, C. and Fischer, F. and Weinl, M. and Stritzker, B.}}, issn = {{0168-583X}}, journal = {{Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms}}, number = {{8-9}}, pages = {{1394--1397}}, publisher = {{Elsevier BV}}, title = {{{Regular surface patterns by local swelling induced by He implantation into silicon through nanosphere lithography masks}}}, doi = {{10.1016/j.nimb.2009.01.052}}, volume = {{267}}, year = {{2009}}, } @article{4223, abstract = {{The formation of a thick protective oxide layer on NiTi by plasma immersion ion implantation (PIII) for medical devices is an established technology on the laboratory scale. It is shown here that by pre-implantation with either 180 keV Ni or low fluence of 190 MeV Au ions, a radiation suppressed growth of the oxide layer of up to 40% is observed. At higher Au fluence and higher PIII temperatures, this changes into an enhancement of 25–40%. Different amorphisation mechanisms or disorder formation is proposed as the underlying effect.}}, author = {{Lutz, J. and Gerlach, J.W. and Lindner, Jörg and Assmann, W. and Mändl, S.}}, issn = {{0168-583X}}, journal = {{Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms}}, number = {{8-9}}, pages = {{1634--1637}}, publisher = {{Elsevier BV}}, title = {{{Radiation suppressed oxide growth in the system Ni–Ti–O}}}, doi = {{10.1016/j.nimb.2009.01.068}}, volume = {{267}}, year = {{2009}}, } @article{4225, abstract = {{EPR and ESE in nitrogen doped 4H- and 6H-SiC show besides the well known triplet lines of 14N on quasi-cubic (Nc,k) and hexagonal (Nc,h) sites additional lines (Nx) of comparatively low intensity providing half the hf splitting of Nc,k. Frequently re-interpreted as spin-forbidden lines, arising from Nc,k pairs and triads or resulting from hopping conductivity, only recently the theoretical calculation of the corresponding g-tensors lead to a tentative model of distant NC donor pairs on inequivalent lattice sites which are coupled to S = 1 assuming a fine-structure splitting too small to be observed in the EPR and ESE experiments. In this work, we present ESE nutation measurements confirming S = 1 for the Nx center. Analysing the nutation frequencies in comparison with that of the Nc,k (S = 1/2) spectrum as well as the line width of ESE and EPR spectra we obtain a rough estimate between 5×104 cm-1 and 50×104 cm-1 for the fine-structure splitting demonstrating efficient spin-coupling between nitrogen donors in 4H-SiC.}}, author = {{Savchenko, D.V. and Pöppl, Andreas and Kalabukhova, Ekaterina N. and Greulich-Weber, Siegmund and Rauls, Eva and Schmidt, Wolf Gero and Gerstmann, Uwe}}, issn = {{1662-9752}}, journal = {{Materials Science Forum}}, pages = {{343--346}}, publisher = {{Trans Tech Publications}}, title = {{{Spin-Coupling in Heavily Nitrogen-Doped 4H-SiC}}}, doi = {{10.4028/www.scientific.net/msf.615-617.343}}, volume = {{615-617}}, year = {{2009}}, } @article{4226, abstract = {{In non-annealed 6H-SiC samples that were electron irradiated at low temperature, a new EPR signal due to a S =1 defect center with exceptionally large zero-field splitting (D= +652104cm1,E=8104cm1) has been observed under illumination. A positive sign of D demonstrates that the spin–orbit contribution to the zero-field splitting exceeds by far that of the spin–spin interaction. A principal axis of the fine-structure tilted by 59 1 against the crystal c -axis as well as the exceptionally high zero-field splitting D can be qualitatively understood by the occurrence of additional close-lying defect levels in defect clusters resulting in comparatively large second-order spin–orbit coupling. A tentative assignment to vacancy clusters is supported by the observed annealing behavior.}}, author = {{Scholle, A. and Greulich-Weber, S. and Rauls, E. and Schmidt, W.G. and Gerstmann, U.}}, issn = {{0921-4526}}, journal = {{Physica B: Condensed Matter}}, number = {{23-24}}, pages = {{4742--4744}}, publisher = {{Elsevier BV}}, title = {{{Vacancy clusters created via room temperature irradiation in 6H-SiC}}}, doi = {{10.1016/j.physb.2009.08.123}}, volume = {{404}}, year = {{2009}}, }