@inbook{2596, author = {{Betz, Stefan}}, booktitle = {{E-Business im industriellen Management - Theoretische Fundierung und praktische Umsetzung im Mittelstand}}, editor = {{Betz, Stefan}}, pages = {{91 -- 109}}, title = {{{Auswahl einer E-Procurement-Strategie als betriebswirtschaftliches Entscheidungsproblem}}}, year = {{2004}}, } @article{26152, abstract = {{A model for simulation of the three-dimensional morphology of nano-structured aggregates formed by concurrent coagulation and sintering is presented. Diffusion controlled cluster–cluster aggregation is assumed to be the prevailing coagulation mechanism which is implemented using a Monte–Carlo algorithm. Sintering is modeled as a successive overlapping of spherical primary particles, which are allowed to grow as to preserve overall mass. Simulations are characterized by individual ratios τ of characteristic collision to fusion time. A number of resulting aggregate-structures is displayed and reveals structure formation by coagulation and sintering for different values of τ. These aggregates are described qualitatively and quantitatively by their mass fractal dimension Df and radius of gyration. The fractal dimension increases from 1.86 for pure aggregation to ≈ 2.75 for equal characteristic time scales. As sintering turns out to be more and more relevant, increasingly compact aggregates start to form and the radius of gyration decreases significantly. The simulation results clearly reveal a strong dependence of the fractal dimension on the kinetics of the concurrent coagulation and sintering processes. Considering appropriate values of Df in aerosol process simulations may therefore be important in many cases.}}, author = {{Schmid, Hans-Joachim and Tejwani, Saurabh and Artelt, Christian and Peukert, Wolfgang}}, issn = {{1388-0764}}, journal = {{Journal of Nanoparticle Research}}, number = {{6}}, pages = {{613--626}}, title = {{{Monte Carlo simulation of aggregate morphology for simultaneous coagulation and sintering}}}, doi = {{10.1007/s11051-004-2161-x}}, volume = {{6}}, year = {{2004}}, } @article{26154, abstract = {{A high-temperature short residence time flow reactor system has been realized for the investigation of the gas phase sintering kinetics of nanoparticles separated from all other synthesis mechanisms, e.g., chemical reaction, nucleation, coagulation and condensation. Major components are a hot-wall tubular reactor for the production of unsintered aggregates consisting of spherical primary particles in the size range 10–80 nm and a sintering reactor for the investigation of the sintering kinetics at well-defined temperature and residence time history. Therefore, rapid heating and quenching of the particles at the beginning and at the end of the reaction zone, respectively, is maintained. Main parameters in the sintering reactor are: temperatures up to 1873 K and residence times in the range 8–1000 ms. The reactor conditions are characterized by temperature profile measurements with a newly constructed suction thermocouple probe and by computational fluid dynamics simulations of the residence time distributions. Exemplary results of the sintering of silica nanoparticles obtained by transmission electron microscopy analysis are presented.}}, author = {{Kirchhof, Martin J. and Schmid, Hans-Joachim and Peukert, Wolfgang}}, issn = {{0034-6748}}, journal = {{Review of Scientific Instruments}}, number = {{11}}, pages = {{4833--4840}}, title = {{{Reactor system for the study of high-temperature short-time sintering of nanoparticles}}}, doi = {{10.1063/1.1809258}}, volume = {{75}}, year = {{2004}}, } @article{26155, author = {{Messerer, A. and Schmid, Hans-Joachim and Knab, C. and Pöschl, U. and Nießner, R.}}, issn = {{0009-286X}}, journal = {{Chemie Ingenieur Technik}}, number = {{8}}, pages = {{1092--1096}}, title = {{{Erhöhung der Abscheidung ultrafeiner Dieselrußpartikeln durch Mikrokugelbeschichtung auf metallträgerbasierten Katalysatorstrukturen}}}, doi = {{10.1002/cite.200403418}}, volume = {{76}}, year = {{2004}}, } @inproceedings{26411, author = {{Volbert, Klaus}}, booktitle = {{Proceedings of the 2004 joint workshop on Foundations of mobile computing - DIALM-POMC '04}}, title = {{{Experimental analysis of adjustable sectorized topologies for static ad hoc networks}}}, doi = {{10.1145/1022630.1022646}}, year = {{2004}}, } @article{26813, author = {{Hellmich, Frank}}, journal = {{Mathematikunterricht }}, number = {{1/2}}, pages = {{47--53}}, title = {{{Inhaltliche, kontextuelle und aktivitätsbezogene Aspekte bei räumlich-geometrischen Problemstellungen}}}, volume = {{50}}, year = {{2004}}, } @book{26845, author = {{Hellmich, Frank and Grüßing , Meike}}, publisher = {{Carl von Ossietzky Universität Oldenburg}}, title = {{{Aufgabenstellungen zur Erfassung mathematischer Kompetenz im vierten Schuljahr}}}, year = {{2004}}, } @inproceedings{3233, author = {{Wehrheim, Heike}}, booktitle = {{Architecting Systems with Trustworthy Components, International Seminar, Dagstuhl Castle, Germany, December 12-17, 2004. Revised Selected Papers}}, editor = {{H. Reussner, Ralf and A. Stafford, Judith and A. Szyperski, Clemens}}, pages = {{84----102}}, title = {{{Refinement and Consistency in Component Models with Multiple Views}}}, doi = {{10.1007/11786160_5}}, year = {{2004}}, } @inproceedings{3234, author = {{Möller, Michael and Olderog, Ernst-Rüdiger and Rasch, Holger and Wehrheim, Heike}}, booktitle = {{Integrated Formal Methods, 4th International Conference, {IFM} 2004, Canterbury, UK, April 4-7, 2004, Proceedings}}, editor = {{A. Boiten, Eerke and Derrick, John and Smith, Graeme}}, pages = {{267----286}}, title = {{{Linking {CSP-OZ} with {UML} and Java: {A} Case Study}}}, doi = {{10.1007/978-3-540-24756-2_15}}, year = {{2004}}, } @inproceedings{3235, author = {{Wehrheim, Heike}}, booktitle = {{Language Engineering for Model-Driven Software Development, 29. February - 5. March 2004}}, editor = {{B{\'{e}}zivin, Jean and Heckel, Reiko}}, title = {{{Refinement and Consistency in Multiview Models}}}, year = {{2004}}, }