Institute's Colloquium (Archive)

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Tuesday, 20.12.2016, 14:00 (WIAS-ESH)
Dr. M.-Th. Wolfram, University of Warwick, Mathematics Institute / Johann Radon Institute Linz (RICAM), Austria:
Applied PDE in the socio-economic sciences
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
In recent years nonlinear PDE models have been used successfully in various applications in socio-economic sciences. For example to describe opinion for- mation and knowledge growth in a society, or the collective dynamics of large pedestrian crowds.
In this talk we focus on two PDE models for socio-economic problems. First a Boltzmann mean- eld game approach to describe knowledge and economic growth in a society; and second a nonlinear PDE model for interacting pedes- trian ows. We start by discussing the underlying microscopic modelling as- sumptions as well as the corresponding mean- eld equations. Then we focus on the existence and linear stability of solutions in either case. Finally we construct special solutions, which relate to sustained economic growth or segregation of flows, and illustrate the dynamics of both models with numerical simulations.
Monday, 19.12.2016, 14:00 (WIAS-ESH)
Dr. B. Zwicknagl, Universität Bonn, Germany:
Variational analysis of microstructures in low-hysteresis shape memory alloys
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
The formation of patterns in solids is often explained as the result of a competition between an elastic bulk energy and a higher order surface energy. As an example we will discuss microstructures in shape memory alloys, which are usually modeled by singularly perturbed non-convex bulk energies. The main focus will be on recent analytical results for shape memory alloys which have been found experimentally to have particularly low hysteresis.
Monday, 28.11.2016, 14:00 (WIAS-ESH)
Dr. F. Hildebrand, Robert Bosch GmbH, Germany:
Technological challenges and chances of Li-metal solid state batteries
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Wednesday, 09.11.2016, 14:00 (WIAS-ESH)
Prof. Dr. M. Kohlhase, Friedrich-Alexander-Universität Erlangen/Nürnberg, Germany:
FrameIT: From Serious Games to Modeling and Applying Mathematical Models
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Mathematical modeling is the key tool that drives modern science, technology engineering, and medicine (STEM). It comprises data about the respective situations & phenomena and models (e.g. differential equations) that allow to draw inferences and make predictions from the data.
STEM data has seen a lot of attention to support its collection, storage, curation, and presentation by computers, and large public and private data repositories have been established. The models themselves have largely remained in the pen-and-paper world of mathematics, and have been transformed into programs on a case-by-case basis. In particular, the question on how to model the models declaratively for computer support is largely unresolved, and as a consequence we do not have collections of models as a resource.
In this talk we will present the knowledge-based FrameIT method, which represents mathematical models and the knowledge backing it in a theory graph whose nodes (theories) are logic-based representations of the mathematical objects, their assumptions, and properties and whose edges (theory morphisms) are meaning-preserving mappings. The critical realization utilized by the FrameIT method is that the application of a mathematical model can be represented as an extension of the model theory graph by special theories representing the situation and phenomena and that the application mapping naturally becomes a theory morphism. This gives an abstract framework for modelling mathematical modelling and makes the models into represented objects that can be collected, curated, presented, and reused.
The FrameIT method has been implemented and tested in the context of serious games for mathematics. We will present that work in the talk and discuss how the very simple models (highschool math) used there can be scaled to realistic models in the STEM fields. We also discuss the OMDoc/MMT infrastructure for collection, storage, curation, and presentation of theory graphs and how this can serve as a basis for a repository of mathematical models.
Monday, 07.11.2016, 14:00 (WIAS-ESH)
Dr. A. Carpentier, Universität Potsdam, Germany:
Sequential sampling and uncertainty quantification
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
This talk will cover two complementary topics : sequential sampling and uncertainty quantification.
The automatisation of sequential decision making in an uncertain environment, also called sequential sampling, is a fundamental goal of modern artificial intelligence and machine learning. A simple example of sequential sampling is the best arm identification bandit setting [1], which is a discrete, unstructured and noisy optimisation problem. Recent own results [5] addressing a conjecture from [1] will be presented. They highlight the importance of uncertainty quantification for sequential sampling, and for risk-aware decision making.
Empirical uncertainty quantification of estimation procedures can be simple in parametric, low dimensional situations. However, it becomes challenging and often problematic in high and infinite dimensional models. Indeed, adaptivity to the unknown model complexity becomes key in this case, and uncertainty quantification becomes akin to model estimation, see [6,4]. Such model-adaptive uncertainty quantification can be formalised through the concept of adaptive and honest confidence sets [2]. Recent own results [3,4] related to this concept will be presented.

References
[1] J.Y. Audibert, S. Bubeck. Best arm identification in multi-armed bandits. Journal of Machine Learning Research W&CP COLT, volume 23, pp. 13-22, 2010.
[2] T. Cai and M. Low. An adaptation theory for nonparametric confidence intervals. The Annals of Statistics, volume 32:5, pp. 1805-1840, 2004.
[3] A. Carpentier, J. Eisert, D. Gross, and R. Nickl. Uncertainty Quantification for Matrix Compressed Sensing and Quantum Tomography Problems. ArXiv e-prints, April 2015.
[4] A. Carpentier, O. Klopp, M. Löffler, and R. Nickl. Adaptive confidence sets for matrix completion. ArXiv e-prints, August 2016.
[5] A. Carpentier and A. Locatelli. Tight (Lower) Bounds for the Fixed Budget Best Arm Identification Bandit Problem. Journal of Machine Learning Research W&CP COLT, volume 49, pp. 1-15, 2016.
[6] M. Hoffmann and R. Nickl. On adaptive inference and confidence bands. The Annals of Statistics, volume 39:5, pp. 2383-2409, 2011.
Monday, 27.06.2016, 14:00 (WIAS-ESH)
Prof. Dr. H. G. Matthies, TU Braunschweig, Institut für Wissenschaftliches Rechnen:
Probability, Analysis, and Numerics
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract

Probability theory was axiomatically built on the concept of measure by A. Kolmogorov in the early 1930s, giving the probability measure and the related integral as primary objects and random variables, i.e. measurable functions, as secondary. Not long after Kolmogorov´s work, developments in operator algebras connected to quantum theory in the early 1940s lead to similar results in an approach where algebras of random variables and the expectation functional are the primary objects. Historically this picks up the view implicitly contained in the early probabilistic theory of the Bernoullis.

This algebraic approach allows extensions to more complicated concepts like non-commuting random variables and infinite dimensional function spaces, as it occurs e.g. in quantum field theory, random matrices, and tensor-valued random fields. It not only fully recovers the measure-theoretic approach, but can extend it considerably. For much practical and numerical work, which is often primarily concerned with random variables, expections, and conditioning, it offers an independent theoretical underpinning. In short words, it is "probability without measure theory".

This functional analytic setting has also strong connections to the spectral theory of linear operators, where analogies to integration are apparent if they are looked for. These links extend in a twofold way to the concept of weak distribution, which describes probability on infinite dimensional vector spaces. Here the random elements are represented by linear mappings, and factorisations of linear maps are intimately connected with representations and tensor products, as they appear in numerical approximations.

Taking this conceptual basis of vector spaces, algebras, linear functionals, and operators gives a fresh view on the concepts of expectation and conditioning, as it occurs in applications of Bayes´s theorem.
Monday, 19.10.2015, 14:00 (WIAS-ESH)
Dr. S. Schmitz, Siemens AG:
Probabilistic Design in Gas Turbine Engineering
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Institutskolloquium
Monday, 15.12.2014, 14:00 (WIAS-ESH)
Prof. Dr. S. Christiansen, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH:
Advanced nano-patterned composite materials and their application in energy harvesting and sensing
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
We will report on novel nano-patterned composite materials for sensing and energy harvesting. We rely on a wealth of nano-composites composed of silicon (Si) as well as GaN nanowires (NWs) from chemical vapor deposition (CVD) based processing including NW shaping based on reactive ion etching, plasmonic nano-structures realized by patterning with focused ion beam microscopes (FIB) of thin metal layer or particle (silver, gold) and few layer graphene from CVD processing. The NWs show large surface areas that can chemically be functionalized to account for sensing functionality. The graphene requires proper chemical treatment to permit attachment of functional groups. The chemical routes to nano-materials functionalization will be reported. Sensing mechanisms with functional nano-materials can be e.g. of electrical, optical or mechanical nature. Examples will be given for selected cases. Emphasis will reside on optical detection based on the surface-enhanced Raman scattering (SERS) effect. We will report SERS of graphene layers transferred on arrays of split ring resonators (SRRs). Raman enhancement factors per area up to 75 demonstrate the strong plasmonic coupling between graphene and the metamaterial resonances. The SRR/graphene material offers a perspective to control SERS and may pave the way towards advanced SERS substrates that could lead to the detection of single molecules attached to graphene for bio-chemical sensing. For energy harvesting applications we develop Si and GaN nanowires with which Mie modes can be controlled and efficient absorption of solar light can be tuned. The integration of NWs in thin film solarcell concepts with efficiency potential >>15% will be demonstrated. The same type of Si NWs and their applicability to solarfuels generation will be shown.

Further Informations
Presentation slides
Monday, 10.11.2014, 14:00 (WIAS-ESH)
Th. Schröder/G. Capellini, Leibniz-Institut für innovative Mikroelektronik (IHP):
Modern Materials Research for "More than Moore" Silicon Microelectronics (T. Schröder) / A Si CMOS compatible Ge laser source on Silicon (G. Capellini)
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 03.11.2014, 14:00 (WIAS-ESH)
N. Triantafyllidis, Ecole Polytechnique, Laboratoire de Mecanique des Solides & Departement de Mecanique:
Electromagnetic forming: A new coupled variational formulation and solution algorithms
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 30.06.2014, 14:00 (WIAS-ESH)
Prof. Dr. J. Neugebauer, Max-Planck-Institut für Eisenforschung, Düsseldorf:
Efficient coarse graining of stochastic high-dimensional configuration spaces as fundament for a fully ab initio based materials design
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
A recurring mathematical challenge in developing simulation techniques to describe and predict materials properties on the computer is the occurrence of interacting many-particle systems on all relevant length and time scales. In the talk I will give a brief overview about the concepts and methods we have developed over the last years and that allow us to describe materials properties from the quantum mechanical level all the way up to engineering quantities. A particular emphasize will be put on novel algorithmic strategies to accurately yet computationally efficiently coarse grain the sampling of stochastic high-dimensional configuration spaces. Applying these strategies allows to use highly accurate but computationally expensive ab initio calculations as input and thus to reach a predictive accuracy that was hitherto not achievable. The performance of this approach will be discussed for a few examples: The design of next-generation ultra-high-strength steels, medical implants with tailored elastic properties but also how to address failure mechanisms that often delay or prevent the introduction of new materials.
Monday, 27.01.2014, 14:00 (WIAS-ESH)
Prof. Dr. E. Rocca, WIAS Berlin:
Entropic solutions for systems of PDEs arising in complex fluids dynamics
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
The main aim of the talk will be to show how to reinterpret the concept of weak solution satisfying a suitable energy conservation and entropy inequality - recently introduced by E. Feireisl and coauthors for a problem of heat conduction in fluids - in order to deal with certain classes of complex fluids dynamics. In many cases indeed the resulting PDE systems dysplay high order nonlinearities due mainly to quadratic forcing terms. The main idea consists in replacing, in the weak formulation, these PDEs by an equality representing energy conservation complemented with a differential inequality describing production of entropy. In this way, the thermodynamical consistency is preserved, but the entropic formulation is more tractable mathematically. This solution notion has been already successfully applied to the analysis of non-isothermal liquid crystals models and to the case of the evolution of a non-isothermal mixture of two different viscous incompressible fluids of the same density. Abstract including references (in pdf format)

Further Informations
Institutskolloquium
Monday, 13.01.2014, 13:00 (WIAS-ESH)
Prof. Dr. E. Valdinoci, WIAS Berlin:
Some nonlocal aspects of partial differential equations and free boundary problems.
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
We will discuss the notion of fractional, nonlocal diffusive operators and we will present some recent mathematical results with applications to different fields, such as: nonlocal phase transitions, nonlocal quantum mechanics, crystal dislocation, nonlocal free boundary problems.
Thursday, 12.12.2013, 14:00 (WIAS-405-406)
O. Knoth, Leibniz-Institut für Troposphärenforschung e.V. (TROPOS):
Multirate time integration methods for the simulation of the atmosphere
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406

Abstract
In this talk an overview is given on multirate time integration methods developed over the years for the integration of the compressible Euler equation and advection-diffusion-reaction equations. Physical and chemical processes in the atmosphere occur on different time scales ranging from seconds to hours and days. Let us mention waves of different speeds in the atmosphere, turbulent diffusion, condensation of water vapor, temporal emission patterns, or photo chemistry. Further time scales come in to play due to the shallow nature of the atmosphere and the huge computational area in case of simulations of the whole globe. To handle these problems anisotropic grids with different grid sizes are used in the vertical and horizontal direction and additional local grid refinement is applied in the horizontal direction. In our solution strategy we follow the method of lines, first discretize in space and then solve in a second stage a huge system of ordinary differential equations (ODE) in time. Most of the proposed time integration methods originate from the idea of source splitting and the recursive use of Runge-Kutta like methods. At each stage of these Runge-Kutta methods again an ODE has to be solved but now only a part of the original right hand side is taken into account whereas the rest act as an additional constant source term. This idea can than be applied again to the subproblems. For these methods order conditions are derived and different strategies for determining reliable schemes with good stability properties will be explained. Two special applications are multirate methods for the advection equation on locally refined grids and generalized split-explicit methods for the compressible Euler equation.

Further Informations
Institutskolloquium
Monday, 02.12.2013, 14:00 (WIAS-ESH)
Dr. K. Wünnemann/D. Elbeshausen, Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung:
Computer simulations of meteorite impact processes: A multi-material, multi-rheology CFD-approach for compressible flows
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Impact cratering on planetary surfaces is one of the most important geological processes in the solar system. The cratered landscapes such as on the Moon, Mars or Mercury testify to the importance of collision events during the evolution of planets. Although remnants of meteorite impacts are rare on Earth it is generally accepted that impact events played an important role in the evolution of the biosphere. On the other hand impacts pose a threat to life on earth. 65 Mio years ago the dinosaurs were wiped out by the impact of a 10 km diameter asteroid striking the Earth at approx. 20 km/s. A quantitative understanding of impact processes can be obtained by the analysis of remnants of impacts from the geological record, by analogue experiments, and numerical modelling. The latter is the main topic of this presentation. Numerical simulations of meteorite impacts require a special type of computer codes, so-called ?hydrocodes?. A hydrocode may be loosely defined as a code designed to solve large deformation, finite strain transient problems that occur on a short time scale. While material strength is neglected in Eulerian codes used for gas dynamics, it is a key component of hydrocodes. In contrast to structural analysis codes, the energy equation is integrated in time, and the deviatoric and pressure terms in the stress tensor are usually modelled separately. The solution is advanced in time using an explicit integration scheme because stress waves and shocks are an important part of the solution, and they must be resolved accurately in both space and time. We will describe modelling approaches to investigate hypervelocity impact processes and shock wave propagation on different scale ranging from millimetres to thousands of kilometres. Besides an efficient parallelized numerical solution of partial differential equations by finite volume technique on Eulerian grids the parameterisation of material properties poses the biggest challenge in the simulation of impact processes. Material modelling in terms thermodynamic behaviour and mechanical response of large, rapid deformation is key for realistic description of the processes.
Monday, 03.06.2013, 14:00 (WIAS-ESH)
Dr. R. Scholz, Technische Universität Dresden, Institut für Angewandte Photophysik (IAPP):
Optoelektronische Bauelemente aus organischen Halbleitern: Simulation von spektroskopischen Eigenschaften und elektronischem Transport
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Institutskolloquium
Monday, 29.04.2013, 14:00 (WIAS-ESH)
Dr.-Ing. J. Höntschel, GLOBALFOUNDRIES Dresden KG, Technology Development (Device):
Advanced VLSI CMOS Technology Scaling - The industry approach from classical scaling towards 3D device integration
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Within the semiconductor industry pure leading edge foundries serve a special mission by delivering state-of-the-art competitive logic performance with a strong focus on system-on-chip (SoC). Therefore they have to support a broad portfolio of different technology options on each node and GLOBALFOUNDRIES is an industry leader by representing this particular business model. To achieve the "high performance per watt" figure of merit technology elements like PD-SOI, strained-Si, an aggressive junction scaling as well as HKMG is needed together with an efficient multiple core- and power-efficient design. Those technology elements were developed and optimized for multiple generations beginning from an 180nm to a 32/28nm technology. For taking the next steps on further device scaling into 20nm VLSI CMOS technologies and beyond several challenges will occur, which will be discussed in the presentation. Future technologies will push a planar transistor technology to its physical limits and subsequent technologies require substantial innovations in process architecture and 3D device concepts. Two possible technology approaches will be discussed such as Multi-Gate-FETs/FinFETs and Extreme-Thin(ET)-SOI/Ultra-Thin-Box(UTB) devices to continue More Moore and More than Moore.
Monday, 22.04.2013, 15:00 (WIAS-ESH)
Prof. Dr. M. Hairer, The University of Warwick, Department of Mathematics:
Dynamics near criticality
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 28.01.2013, 14:00 (WIAS-ESH)
Prof. Dr. K. Hutter, ETH Zürich, Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie:
Cryospheric IBVP's. In support of general circulation models of the earth's climate evolution
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Part II of WIAS launching event for "Mathematics of Planet Earth 2013"
Presentation slides (as presented)
Presentation slides (extended version)
Monday, 21.01.2013, 13:30 (WIAS-ESH)
Dr. G. Kirillin, Leibniz Institute of Freshwater Ecology and Inland Fisheries Berlin (IGB):
Ice-covered freshwater-lakes: natural laboratories for investigation of buoyancy flows
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Convection driven by gravitational instability is a widespread phenomenon in the geophysical fluid dynamics, dynamics of stars and planetary interiors. In contrast to the quasi-homogeneous small-scale turbulence, convection is distinguished by the cell-like coherent structure of the flow. Absence of wind shear and non-linear dependene of freshwater density on temperature in vicinity of 4°C are characteristic features of ice-covered lakes. Therefore, a variety of convective flows develop there, driven by solar radiation penetrating the ice, and by salt fluxes at the ice-water and the water-sediment interfaces. In our field studies on ice-covered lakes, we apply modern measurement techniques, like microstructure profiling and acoustic doppler velocimetry, which deliver direct estimations of the mixing characteristics, comparable with the output of the eddy-resolving LES and DNS models. Providing a rare example of 'pure' convection in the natural conditions, ice-covered lakes serve as natural laboratories for investigation of convective mixing and for testing of CFD models. Apart from general geophysical studies, a number of ecological applications exist, where field studies on convection can be effectively combined with advanced mathematical modelling of convective mixing.

Further Informations
Part I of WIAS launching event for "Mathematics of Planet Earth 2013"
Presentation slides
Monday, 10.12.2012, 14:00 (WIAS-ESH)
Dr. M. W. Wuttke, Leibniz Institute for Applied Geophysics (LIAG):
Unterirdische Kohlebrände in Nord-China: Lokales Problem mit globaler Wirkung und eine Herausforderung für die angewandte Geophysik
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract

Im LIAG untersuchen wir die oberen Bereiche der Erdkruste, die anthropogen beeinflussbar und für eine wirtschaftliche Nutzung und Daseinsvorsorge wichtig sind. Abhängig von der gewählten räumlichen und zeitlichen Skala werden diese Bereiche statisch durch Struktur- oder dynamisch durch Prozess-Modelle beschrieben. Letztere werden im Wesentlichen durch den gekoppelten Transport von Energie (thermisch und mechanisch) und Masse (hauptsächlich Fluide) und deren Umwandlungen bestimmt. Diese Prozesse ordnet man gewöhnlich unter die Begriffe thermisch (T), hydraulisch (H), mechanisch (M) und chemisch (C) ein, in der Gesamtheit werden sie als gekoppelte THMC-Prozesse bezeichnet.

Im Kohlebergbau treten besonders starke Kopplungen zwischen THMC-Prozessen auf, wenn die Kohle in der natürlichen Lagerstätte durch Sauerstoffzufuhr anfängt zu brennen. Zusätzlich zu den thermischen kommt es zu mechanischen Belastungen des Gesteins, was letztlich in Bruchvorgängen resultiert. Die entstandenen Brüche bilden Wegsamkeiten für die Sauerstoffzufuhr, wodurch sich das Feuer selbst anfacht.

Das LIAG war von 2003 bis 2010 an dem BMBF Verbundvorhaben ?Innovative Technologien zur Erforschung, Löschung und Überwachung von Kohlebränden in Nord China? beteiligt. In diesem Projekt stand das Prozessverständnis der Kohlebrände sowie die Gewinnung von Kenntnissen zur Effizienz von Löschmethoden im Vordergrund der wissenschaftlichen Untersuchungen. Hierbei hat das LIAG als Schwerpunkt die numerische Modellierung der Brandvorgänge inklusive der Löschverfahren bearbeitet. Begleitend wurden geothermische Messungen in den Brandgebieten durchgeführt und dazu auch neue Hochtemperatur-Messtechniken entwickelt. Die erarbeitete Expertise wird zur Zeit in einer Kooperation mit dem Xinjiang Institute of Coal Science und dem Xinjiang Coal fire Fighting Bureau in Urumqi, Xinjiang, Volksrepublik China weiterentwickelt.

Die Löschung von Kohlebränden rückt auch im Schatten der Klimaerwärmung als Massnahme zur Reduzierung des anthropogenen Kohlendioxidausstosses in den Blickpunkt. Zur Akkreditierung jeglicher Zertifikate für solche Löschungen sind umfangreiche Modellrechnungen notwendig. Hierzu leisten die am LIAG erarbeiteten Methoden einen unverzichtbaren Beitrag.

Die bei der Untersuchung von Kohlebränden gewonnenen Erfahrungen lassen sich unmittelbar auf andere Arbeitsgebiete übertragen. Kohlebrände stellen allerdings eine besondere Herausforderung dar: Schnelle chemische Prozesse mit hohem Energieumsatz treiben den Stofftransport und bewirken mechanische und strukturelle Veränderungen der Umwelt, in der sie stattfinden. Alle Prozesse laufen sowohl räumlich, als auch zeitlich auf vielen verschiedenen Skalen ab. Technische Eingriffe bei den Löschungen stellen zeitlich diskrete Ereignisse dar. Die beteiligten Materialien unterliegen oft Phasenumwandlungen (Verdampfung und Kondensation, Lösung und Ausfällung, Verfestigung), so dass eigentlich immer ein Mehrphasentransport vorliegt. Die realen Situationen zeigen kaum Symmetrien, so dass die Behandlung dreidimensional erfolgen muss.

Die durch die Brandgase berührte Klimaproblematik, die Bedrohung der Ressource Kohle sowie der unmittelbar betroffenen Lebensgebiete machen die Untersuchung von Kohlebränden zu einem wirtschaftlich und gesellschaftlich relevanten Forschungsthema.
Monday, 12.11.2012, 14:00 (WIAS-ESH)
Dr. R. Werp/M. Schmidt, engage AG:
Status Quo und Weiterentwicklungsmöglichkeiten im Bereich Technologietransfer am WIAS
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Ziel des BMBF-finanzierten Förderprogrammes zur sektoralen Verwertung an Institutionen der Leibniz- sowie Helmholtz-Gemeinschaft ist die Professionalisierung des Technologietransfers unter Hinzuziehung von Kompetenzen externer Verwertungspartner. In diesem Kontext arbeitet das WIAS seit April 2011 mit der engage AG an der Erarbeitung und Umsetzung entsprechender Maßnahmen. Im Vortrag wird eine aus den durchgeführten Gesprächen und Marktstudien resultierende erste Bestandsaufnahme mit entsprechenden Empfehlungen vorgestellt und diskutiert.

Further Informations
Presentation slides
Monday, 15.10.2012, 14:00 (WIAS-ESH)
Prof. Dr. W. Dreyer, WIAS:
Overcoming the shortcomings of the Nernst-Planck model
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Our study on electrolytes takes a thermodynamically consistent coupling between mechanics and diffusion into account. It removes some inherent deficiencies of the popular Nernst-Planck model. A boundary problem for the equilibrium processes is used to illustrate the new features of our model.
Monday, 18.06.2012, 14:00 (WIAS-ESH)
Prof. Dr. J. A. Sethian, University of California, Dept. of Mathematics, Berkeley (USA):
Tracking Multiphase Physics: Geometry, Foams, Thin Films, and Biological Cells
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 11.06.2012, 14:00 (WIAS-ESH)
Prof. Dr. S. Lu, Fudan University, School of Mathematical Sciences (Humboldt Fellow at WIAS):
Growth rate identification in the crystallization of polymers
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract

Nucleation and growth mechanisms are important kinetics of the phase transformation model which arises in the crystallization of the polymer materials. In each stage, the nucleation rate and the growth rate have been the crucial coefficients describing the kinetics of the process as well as the properties of the specimens. Moreover, identification of these physical parameters describing the nucleation or the growth mechanisms is essential for controlling the crystallization of polymers and so is a significant subject also from industrial viewpoints.

In this talk, we will revisit the time cone approach in Cahn 1996 where a hyperbolic governing equation is derived for the heterogeneous nucleation rate and spatially homogeneous growth rate. As for the inverse problem, by utilizing the eigenfunction expansion method, we investigate the identification of the growth rate for an isothermal one dimension specimen. Such a problem can be seem as an inverse coefficient problem for a hyperbolic equation which is highly nonlinear with respect to the observation data. A two-step Tikhonov type regularization method is proposed to reconstruct the growth rate provided with the final noisy observation data. Numerical prototype examples are presented to illustrate the validity and effectiveness of the proposed scheme.
Monday, 04.06.2012, 14:00 (WIAS-ESH)
Dr. S. Fortes, California Institute of Technology (WIAS Fellow):
Perturbation Methods for Waves in High-contrast Plasmonic Crystals
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 21.05.2012, 15:30 (WIAS-ESH)
Prof. Dr. V. Capasso, University of Milano, Department of Mathematics:
The role of geometric randomness in the mathematical modeling of Angiogenesis
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 23.04.2012, 17:15 (WIAS-ESH)
Dr. J. Dunlop, Max Planck Institute of Colloids and Interfaces, Department of Biomaterials:
Geometric control of tissue growth
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

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Presentation slides
Monday, 09.01.2012, 17:00 (WIAS-ESH)
Prof. Dr. M. Wakayama, Kyushu University, Institute of Mathematics for Industry:
Remarks on geodesics for multivariate normal models
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract

A complete description of the geodesic curves on the Riemann manifold of multivariate normal distributions equipped with the Fisher information metric has been accomplished by Eriksen in 1987, and later by Calvo and Oller in 1991 but in a different manner. The former describes geodesic curves in terms of an exponential map in somewhat mysterious way and the latter obtains a solution of the differential equation of a geodesic curve explicitly by solving much general system of differential equations. The method what Erikson had taken seems to have a group theoretic nature while it is still unclear. The purposes of this talk are to derive the explicit formula of the geodesic curve from the result obtained by Eriksen and to clarify why such exponential map may give geodesic curves for the one dimensional normal distribution case.

In the beginning of the talk, the speaker will briefly introduce the newly established research institute, "Institute of Mathematics for Industry, Kyushu University".
Monday, 19.12.2011, 17:00 (WIAS-ESH)
M. Becker, Leibniz-Institut für Plasmaforschung und Technologie e.V. (inp), Greifswald:
Hydrodynamische Modelle und numerische Verfahren zur Beschreibung von Niedertemperaturplasmen
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract

M. Becker und D. Loffhagen, INP Greifswald e.V., Felix-Hausdorff-Str. 2, 17489 Greifswald

Niedertemperaturplasmen werden in vielen technologischen Anwendungen eingesetzt. Dazu zählen Plasmabildschirme, Leuchtmittel und die Funktionalisierung von Oberflächen. Ergänzend zu experimentellen Versuchen wird die hydrodynamische Modellierung von Plasmen vielfältig bei der Entwicklung und Optimierung der Anwendungen eingesetzt. Typischerweise werden dabei Bilanzgleichungen für die Teilchendichten und die Stromdichten der Elektronen und Schwerteilchen sowie eine Bilanzgleichung für die Energiedichte der Elektronen gekoppelt mit der Poisson-Gleichung zur selbstkonsistenten Bestimmung des elektrischen Potenzials gelöst.

In dem Vortrag werden gängige Modelle diskutiert und numerischen Verfahren zur Lösung der nichtlinear gekoppelten partiellen Differenzialgleichungen vorgestellt. Dabei wird insbesondere auf Stabilisierungstechniken im Kontext Finiter-Differenzen- und Finiter-Elemente-Verfahren eingegangen, die bei der Modellierung von Niedertemperaturplasmen eingesetzt werden. Vor- und Nachteile der Modelle und Verfahren werden am Beispiel der Modellierung einer Niederdruckglimmentladung in Argon veranschaulicht.

Further Informations
Presentation slides
Monday, 28.11.2011, 17:00 (WIAS-ESH)
S. Markwart/L. Koch, WIAS Berlin:
International mathematical activities: Projects, networking and cooperation of the International Mathematical Union (IMU)
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 28.11.2011, 15:30 (WIAS-ESH)
Dr. Th. Böhme, IAV GmbH - Ingenieurgesellschaft Auto und Verkehr:
Herausforderungen der Elektrifizierung von PkW-Antriebssträngen - Regelungstechnische Ansätze und Methoden
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 31.10.2011, 17:00 (WIAS-ESH)
Prof. Dr. Ch. Elliott, University of Warwick, Mathematics Institute:
Computational surface PDEs
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 27.06.2011, 17:00 (WIAS-ESH)
Prof. Dr. S. Volkwein, Universität Konstanz:
Model reduction for nonlinear problems: Analytical and numerical aspects
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 27.06.2011, 17:00 (WIAS-ESH)
Prof. Dr. S. Volkwein, Universität Konstanz:
Model reduction for nonlinear problems: Analytical and numerical aspects
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 27.06.2011, 15:30 (WIAS-ESH)
Prof. Dr. P. Strasser, Technische Universität Berlin; Die elektrochemische Katalyse, Energie und Materialwissenschaften Gruppe:
Degradation of Pt and Pt alloy nanoparticle catalysts monitored in situ by X-rays
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
in pdf format
Monday, 30.05.2011, 17:00 (WIAS-ESH)
Dr. S. Ganesan, Indian Institute of Science, Bangalore, India / WIAS (Humboldt Fellow):
Finite element simulation of free surface and two-phase flows using moving meshes
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 30.05.2011, 15:30 (WIAS-ESH)
Prof. Dr. A. Mielke, WIAS:
Analysis of multiscale systems driven by functionals
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 18.04.2011, 17:00 (WIAS-ESH)
Dr. M. Wagemaker, TU Delft (The Netherlands), Reactor Institute:
Dynamic solubility limits in the Li-ion battery electrode material LiFePO4
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
presentation slides
Monday, 13.12.2010, 17:00 (WIAS-ESH)
Dr. F. Garwe, Institut für Photonische Technologien Jena (IPHT):
Wechselwirkung von Licht mit metallischen Nanopartikeln in dielektrischer Umgebung
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 29.11.2010, 17:00 (WIAS-ESH)
PD Dr. P. Knobloch, Charles University Prague:
Stabilized finite element methods for convection-diffusion equations
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 29.11.2010, 15:30 (WIAS-ESH)
Prof. M. Stynes, College of Science, Engineering and Food Science Cork; School of Mathematical Sciences:
A new finite element method for singularly perturbed reaction-diffusion problems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 25.10.2010, 17:00 (WIAS-ESH)
Dr. R. Patterson, WIAS:
Stochastic Soot Simulation
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 25.10.2010, 15:30 (WIAS-ESH)
PD Dr. M. Ostermeyer, Innovative Berlin Laser GmbH (IBL):
Realizing excellent beam quality in high power solid state lasers - Search for a design tool
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 31.05.2010, 17:00 (WIAS-ESH)
Prof. Dr. R. Brunsch, Leibniz-Instituts für Agrartechnik Potsdam-Bornim (ATB):
Ansätze zur Verbesserung landwirtschaftlicher Produktionsverfahren durch Modellierung an der Schnittstelle zwischen Biologie und Technik
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 31.05.2010, 15:30 (WIAS-ESH)
Dr. S. Köhler/Dr. H.-U. Balzer, Institut für Agrar- und Stadötkologische Projekte an der Humboldt-Universität zu Berlin (IASP):
Zeitreihenanalysen und experimentelle Erkenntnisse zur Darstellung biologischer Regelvorgänge
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 26.04.2010, 17:00 (WIAS-ESH)
Dr.-Ing. O. Kastner, Ruhr-Universität Bochum, Institut für Werkstoffe:
Microstructure formation and hysteresis in shape memory alloy
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
in pdf format
Monday, 14.12.2009, 17:00 (WIAS-ESH)
Prof. Dr. V. John, WIAS:
Topics in the Numerical Simulation of Population Balance Systems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 14.12.2009, 15:30 (WIAS-ESH)
Prof. Dr. W. König, WIAS:
The Universality Classes in the Parabolic Anderson Model
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 30.11.2009, 17:00 (WIAS-ESH)
Prof. Dr. L. Strüder, Max-Planck-Institut für extraterrestrische Pysik, MPI-Halbleiterlabor:
Halbleiterdetektoren - im Himmel und auf Erden
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract

Am Halbleiterlabor der Max-Planck-Institute für Physik und für extraterrestrische Physik werden Siliziumdetektoren für ionisierende Strahlung entwickelt. Die Energie der Strahlung reicht vom nahen Infrarotlicht über das sichtbare Licht bis hin zur Röntgen- und Gammastrahlung. Auch in den Experimenten der Teilchenphysik an den Hochenergiebeschleunigern werden unsere Sensoren zur präzisen Spurvermessung eingesetzt.

Zunächst werde ich über die Anwendungen der Detektoren in den Institutsexperimenten berichten. Im Vordergrund steht die Röntgenastronomie.

Der Kern des Vortrages konzentriert sich auf die eigenen Entwicklungs- und Fertigungsmgölichkeiten im Halbleiterlabor: Wie entsteht ein Chip - zunchäst im Computer und dann wirklich im Labor? Wie werden die Systeme getestet und auf ihren späteren Einsatz hin vorbereitet? Die Kette von der Idee, der Simulation über die Fertigung hin zum Test bis zum Einsatz im Experiment wird an einem Beispiel erläutert.

Auch Beispiele zum industriellen Einsatz der Detektoren werden aufgeführt, z.B. in der Materialanalyse oder für die medizinische Diagnose.

Der Vortrag endet mit einem Ausblick auf die zukünftigen Vorhaben. Hier stehen die Röntgenmissionen eROSITA und IXO im Vordergrund. Auf der Seite der Gammaastronomie sind es ortsauflösende Gammaspektrometer. Im Optischen arbeiten wir derzeit an einer Hochgeschwindigkeitskamera zum Nachweis von einzelnen optischen Photonen. Für die zukünftigen "Free Electron Laser" in den USA, Japan und Deutschland werden abbildende Röntgensysteme mit extremen dynamischen Bereich benötigt - eine Herausforderung für sie Simulation und die realen Bauelemente.

Further Informations
Presentation slides
Monday, 26.10.2009, 17:00 (WIAS-ESH)
Prof. Dr. B. Witzigmann, Universität Kassel, Fachgebiet Computational Electronics and Photonics:
Computational Modeling of Semiconductor Nanostructures for Optoelectronics
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 26.10.2009, 15:30 (WIAS-ESH)
Prof. Dr. W. Dreyer, WIAS:
Non-monotone constitutive behavior and hysteresis
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 29.06.2009, 17:00 (WIAS-ESH)
E. Diederichs, Freie Univerität Berlin, Institut für Mathematik:
Sparse Non-Gaussian Component Analysis with applications to conformation dynamics of biomolecular systems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
presentation slides
Monday, 29.06.2009, 15:30 (WIAS-ESH)
Dr. O. Omel'chenko:
Synchronization modes in nonlocally coupled phase oscillators
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 25.05.2009, 17:00 (WIAS-ESH)
Prof. Dr. O. Sigmund, Technical University of Denmark, Lungby, Department of Mechanical Engineering, Section for Solid Mechanics:
Topology Optimization and its applications to mechanics and wave propagation problems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 25.05.2009, 15:30 (WIAS-ESH)
Prof. Dr. U. Leonhardt, Universität St. Andrews, UK:
Geometry, light and a wee bit of magic
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Many mass-produced everyday products of modern technology would appear to be completely magical to our ancestors: mobile phones, television, computers, electric light, cars, etc. Some devices that are still perceived as magical or mysterious are about to appear in the laboratory and are not so mysterious after all. For example, the first prototype of an electromagnetic cloaking device has been recently made at Duke university. This device makes an object invisible to microwave radiation of a single frequency and polarization. At Harvard University, first vital steps towards levitating objects on the forces of the quantum vacuum have been made. At St Andrews, we observed first indications of artificial black holes in the laboratory, using extremely short light pulses in photonic-crystal fibres. Invisibility devices, quantum forces and optical black holes have two things in common: they represent applications of Einstein's general relativity in Maxwell's electromagnetism and their practical demonstrations are made possible by modern metamaterials. I will try to elucidate the scientific principles acing behind the scenes of such "pure and applied magic".

Further Informations
Presentation slides
Monday, 27.04.2009, 17:00 (WIAS-ESH)
Prof. Dr. D. Bothe, TU Darmstadt, Mathematical Modelling and Analysis Center for Smart Interfaces:
Modelling and Analysis of transport processes at fluidic interfaces
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Fluid particles like drops or bubbles play a prominent role in numerous applications like multiphase chemical reactors, fuel engines, atomization, drying of liquid sprays, heat exchange and ink-jet printing to mention just a few. One particular development towards process intensification relies on micro-systems, which further enhances the role of inter-material interfaces and requires accurate models and a profound understanding of these. This talk surveys sharp-interface models for two-phase flows with increasing level of physico-chemical interface properties, starting from a simple dividing interface to the case when the interface is a phase for itself with surface viscosity and variable surface tension - the so-called Boussinesq-Scriven surface fluid. For the different levels of interfacial properties, the corresponding mathematical models together with main analytical results are outlined. For some of the models, results of Volume-of-Fluid (VOF)-based numerical approaches are also included.

Further Informations
Presentation slides
Monday, 27.04.2009, 15:30 (WIAS-ESH)
Dr. K. Weichert, Max-Planck-Institut für Festkörperforschung Stuttgart:
LiFePO4 - Defect Chemistry and Phase Transition to FePO4
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 15.12.2008, 17:00 (WIAS-ESH)
Prof. Dr. J.-U. Sommer, Leibniz-Institut für Polymerforschung Dresden (IfP):
Eine kurze Geschichte der Polymerphysik: Von Naturkautschuk zu Nanostrukturen
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Ausgehend von den Entdeckungen der Entropieelastizität und der allgemeinen Struktureigenschaften von Polymeren wird das Konzept der Konformationsentropie als zentrales Paradigma der Polymerphysik vorgestellt. Im Unterschied zu niedermolekularen Systemen führt die große Zahl der inneren Freiheitsgrade eines flexiblen Kettenmoleküls zu neuartigen Eigenschaften, die durch Methoden der statistischen Physik beschrieben werden können. Es wird gezeigt, was Polymerketten und quantenmechanische Teilchen gemeinsam haben und warum die Theorie der Paulschen Fallen auch die Lokalisation von Kopolymeren beschreiben kann. Die Analyse der statistischen Selbstähnlichkeit der Konformationen von Polymerketten führt direkt in das Gebiet der kritischen Phänomene und der Phasenübergänge und gestattet die Verwendung von einfachen Skalenkonzepten zur Lösung komplexer Probleme. Die Methoden der modernen makromolekularen Chemie ermöglichen die Synthese maßgeschneiderter Polymermoleküle, welche sich zu Strukturen unterschiedlicher Symmetrie im Nanometerbereich selbstorganisieren. Die Kontrolle über diese Nanostrukturen, insbesondere zur Modifizierung von Oberflächen und in dünnen Schichten, ist ein Schlüssel zu Materialien mit neuen Funktionalitäten und stellt eine der großen Herausforderungen der modernen Polymerphysik dar.

Further Informations
Presentation slides
Monday, 24.11.2008, 17:00 (WIAS-ESH)
Prof. Dr. B. Rech, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, HMI:
Solarzellen an dünnen Siliziumschichten - Stand der Technik und Herausforderungen für die Zukunft
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 24.11.2008, 15:30 (WIAS-ESH)
Dr. L. Korte, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, HMI:
The amorphous-crystalline silicon interface - key for high efficiency silicon heterojunction solar cells
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
An overview will be presented that summarizes recent developments in amorphous/crystalline silicon (a-Si:H/c-Si) heterojunction solar cell technology and the current understanding of the fundamental device physics. In a Si:H/c Si cells, device performance is crucially dependent on the quality of the a Si:H/c Si heterojunction. Some of the main issues will be discussed that have been identified as being crucial to minimize recombination at the junction and thereby maximize cell efficiency: Wet chemical pre-treatment of the c Si surface prior to a Si:H deposition; optimum doping, which is a trade-off between maximizing band bending and minimizing interface recombination; thermal and plasma post-treatments of the a Si:H/c Si structure. By optimizing these aspects using specifically developed characterization methods such as UV-excited photoelectron spectroscopy and surface photovoltage measurements, we were able to realize (n)a Si:H/(p)c Si and (p)a Si:H/(n)c Si cells with up to 18.5% and 19.8% efficiency, respectively. In both cases, the cells were prepared without the commonly used intrinsic buffer layer.

Further Informations
Presentation slides
Monday, 27.10.2008, 17:00 (WIAS-ESH)
H. Fiebig, Wikimedia Deutschland e.V.; P. Birken, Universität Kassel, AG Analysis und Angewandte Mathematik:
Wissen teilen leicht gemacht: Eine kurze Einführung für Wikipedia-Einsteiger
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 27.10.2008, 15:30 (WIAS-ESH)
Dr. P. Birken, Universität Kassel, AG Analysis und Angewandte Mathematik:
Mathematik in der deutschsprachigen Wikipedia
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 30.06.2008, 17:00 (WIAS-ESH)
Prof. H. Ch. Öttinger, ETH Zürich, Institut für Polymere:
Hydrodynamics, Thermodynamics, and Mathematics
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 30.06.2008, 15:30 (WIAS-ESH)
Prof. S. Heinz, University of Wyoming, Department of Mathematics:
Unified Stochastic and Deterministic Turbulence Models
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
The talk is organized in four parts. The first part describes requirements regarding the numerical simulation of turbulent flows. It will be shown that stochastic methods are needed which generalize deterministic methods such that the closure problems of deterministic equations are solved. The second part describes the basics of stochastic methods and their implied deterministic equations. The modeling of molecular dynamics, turbulent velocity and scalar fields will be discussed. Special emphasis is placed on the question of how existing (FDF and PDF, LES and RANS) methods can be unified. The third part describes the application of stochastic and deterministic methods to both non-reacting and reacting turbulent flow simulations. The integration of RANS and LES for swirling turbulent jet flow simulations will be discussed. It will be shown how the range of applicability of hybrid RANS/PDF methods can be extended such that nonpremixed turbulent combustion simulations can be performed. The fourth part summarizes these developments and describes future activities.
Monday, 26.05.2008, 17:00 (WIAS-ESH)
Prof. Dr. H. Riechert:
Wissenschaftliche Schwerpunkte am Paul-Drude-Institut
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 26.05.2008, 10:00 (WIAS-ESH)
Dr. Ch. J. P. Newton, Hewlett Packard Laboratories Bristol, UK:
Modelling for Paper-Like Displays
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 28.04.2008, 17:00 (WIAS-ESH)
Dr. O. Zindy, WIAS:
Random walks in random environment: localization studies
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 28.04.2008, 15:30 (WIAS-406)
Dr. Ch. Lechner, WIAS:
Numerical Simulation of Czochralski Crystal Growth
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)

Further Informations
Presentation slides
Monday, 17.12.2007, 17:00 (WIAS-ESH)
Dr. M. Welk, Universität des Saarlandes Saarbrücken, Naturwissenschaftlich-Technische Fakultät I (Mathematik und Informatik):
Robust variational methods for the deconvolution of images
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 17.12.2007, 15:30 (WIAS-ESH)
Dr. M. Birkner, WIAS:
Inference for coalescents with multiple collisions
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 26.11.2007, 17:00 (WIAS-ESH)
Prof. Dr. P. Vogl, Technische Universität München, Walter Schottky Institut:
The 3D nanometer device project nextnano: Concepts, Methods, Results
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
nextnano is a versatile software for the simulation of three-dimensional nanometer-scale quantum structures and semiconductor devices. We will outline some of the basic physical concepts and numerical methods that have been developed for nextnano, an international collaborative effort involving many physicists, mathematicians, and programmers. In addition, we will present several application examples.

Further Informations
Presentation slides
Monday, 26.11.2007, 15:30 (WIAS-ESH)
Dr. B. Michel, Simuloptics GmbH Schwabach:
Inverses Streuproblem bei der optischen Partikelcharakterisierung
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 29.10.2007, 17:00 (WIAS-ESH)
Dr. H. Wenzel, Ferdinand-Braun-Institut für Höchstfrequenztechnik Berlin (FBH):
High-brightness diode lasers - achievements and challenges
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 29.10.2007, 15:30 (WIAS-ESH)
Prof. Dr.-Ing. J. Villain, Fachhochschule Augsburg, FB Elektrotechnik:
Struktur und Eigenschaften miniaturisierter bleifreier Lötverbindungen
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 25.06.2007, 17:00 (WIAS-ESH)
H. Si, WIAS:
3D boundary conforming Delaunay mesh generation
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 25.06.2007, 15:30 (WIAS-ESH)
PD Dr. W. Dreyer, WIAS:
Phasenübergänge mit Beteiligung von Erhaltungssätzen
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 16.04.2007, 17:00 (WIAS-ESH)
Dr. H.-Chr. Kaiser, WIAS:
A Drift-Diffusion Model with Fully Nonlocal State Equations for Heterogeneous Semiconductor Materials
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 12.02.2007, 17:00 (WIAS-ESH)
M. Lichtner, WIAS:
Principle of Linearized Stability and Invariant Manifold Theorem for Semilinear Hyperbolic Systems with Applications to Semiconductor Laser Dynamics
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 11.12.2006, 17:00 (WIAS-ESH)
PD Dr. B. Wagner, WIAS:
Instabilities of Nanoscopic films
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 27.11.2006, 17:00 (WIAS-ESH)
Dr. T. Köhler/M. Teuchert, WIAS:
Fördermöglichkeiten für Grundlagenforschung und Anwendungen im 7. Rahmenprogramm der EU
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 13.11.2006, 17:00 (WIAS-ESH)
R. P. H. Faassen, Technische Universiteit Eindhoven, Department of Mechanical Eingeneering:
Modelling and detection of machine tool chatter in high speed milling
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

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Presentation slides
Monday, 16.10.2006, 17:00 (WIAS-ESH)
Prof. Dr. A. Korol, University of Haifa, Institute of Evolution:
Mapping the Genome: Mathematical and computational challenges
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

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Presentation slides
Monday, 03.07.2006, 17:00 (WIAS-ESH)
Sergey S. Zelik, Institute for Information Transition Problems, Russian Academy of Sciences (Weierstrass Fellow):
Interaction of solitons in dissipative systems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 26.06.2006, 17:00 (WIAS-ESH)
Dr. X. Yao, Tsinghua Universität Peking (Weierstrass Fellow):
Random graph and complex networks
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 19.06.2006, 17:00 (WIAS-ESH)
Prof. Dr. P. Fratzl, Max-Planck-Institut für Kolloid- und Grenzflächenforschung Potsdam, Abteilung Biomaterialien:
Adaptive Materialien der Natur
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 29.05.2006, 17:00 (WIAS-ESH)
Prof. Dr. F. Jeltsch, Universität Potsdam, Institut für Biochemie und Biologie:
Simulating savanna dynamics: from system stability to biodiversity
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 08.05.2006, 17:00 (WIAS-ESH)
Dr. M. G. Lüling, Schlumberger Paris:
CO2 Underground Storage to Clean the Atmosphere
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 06.02.2006, 17:00 (WIAS-ESH)
Dr. A. Rolo Naranjo, Instituto Superior de Tecnologías y Ciencias Aplicadas Havanna (Kuba):
Computational tools for signal processing applications from industry and bioinformatics
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Computational tools for signal processing applications from industry and bioinformatics

Further Informations
Presentation slides
Monday, 23.01.2006, 17:00 (WIAS-ESH)
Prof. Dr. K. Zhang, Philips Semiconductors Eindhoven:
Some Trends and Impacts of Micro/Nanoelectronics
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 16.01.2006, 17:00 (WIAS-ESH)
Dr. D. Zheng, Continental AG Hannover:
Tire FEM simulation at Continental AG
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 19.12.2005, 17:00 (WIAS-ESH)
PD Dr. R. Ramlau, ohann Radon Institute for Computational and Applied Mathematics (RICAM) Linz:
Unwuchtbestimmungen in rotierenden Systemen - Theorie und Anwendungen
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 31.10.2005, 17:00 (WIAS-ESH)
Prof. Dr. S. Siltanen, GE Healthcare, Tuusula, Finnland:
Low dose 3-dimensional medical X-ray imaging
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 25.07.2005, 17:00 (WIAS-ESH)
Prof. Dr. K. Jacobs, Universität des Saarlandes, FR Experimentalphysik:
Dynamik von Flüssigkeiten in der Nähe einer Grenzfläche: Eine experimentelle Sicht
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 27.06.2005, 17:00 (WIAS-ESH)
PD Dr. H. Voss, Citigroup Biomedical Imaging Center, Weill Medical College of Cornell University:
Understanding functional connectivity of the brain: Diffusion tensor magnetic resonance imaging
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 13.06.2005, 17:00 (WIAS-ESH)
Dr. R. Giese, Gaswärme-Institut Essen:
Energetische Optimierung von Thermoprozessanlagen
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 06.06.2005, 17:00 (WIAS-ESH)
Prof. Dr. L. Overbeck, HypoVereinsbank / Justus-Liebig-Universität Gießen:
Valuation of Structured Credit Products
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 09.05.2005, 17:00 (WIAS-ESH)
Prof. Dr. P. Maass, Universität Bremen, Zentrum für Technomathematik:
Wavelets in der Datenanalyse - von Finanzdaten bis zur Windmessung
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 25.04.2005, 17:00 (WIAS-ESH)
Dr. H. Wöhler, autronic-MELCHERS GmbH Karlsruhe:
Modellierung und Simulation von LCDs
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Friday, 08.04.2005, 17:00 (WIAS-ESH)
PD Dr. F. Falk, Institut für Physikalische Hochtechnologie Jena (IPHT):
Laserkristallisation von Halbleitern
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 13.12.2004, 17:00 (WIAS-ESH)
Prof. Dr. H.-J. Schwarzmaier, Klinikum Krefeld:
Grundlagen der laserinduzierten, interstitiellen Thermotherapie
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 06.12.2004, 17:00 (WIAS-ESH)
Prof. Dr. M. Böhm, TFH Berlin / ITWM Kaiserslautern:
Online-Inspektion von metallischen Oberflächen
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Monday, 22.11.2004, 17:00 (WIAS-ESH)
Dr. E. Barth, Universität Lübeck, Institut für Neuro- und Bioinformatik:
Mathematische Probleme des künstlichen Sehens aus der Perspektive spezifischer Anwendungen
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 01.11.2004, 17:00 (WIAS-ESH)
PD Dr. J. Timmer, Albert-Ludwigs-Universität Freiburg, Zentrum für Datenanalyse und Modellbildung:
Data-based modeling of the dynamics of a cellular signaling pathway
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 25.10.2004, 17:00 (WIAS-ESH)
Dr. H. Gross/Dr. B. Kleemann, Carl Zeiss AG Oberkochen:
Periodische Helmholtz-Solver in der elektromagnetischen Optik (Kleemann)
Inverse Probleme in der klassischen Optik (Gross)
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides: Kleemann, Gross
Monday, 20.09.2004, 17:00 (WIAS-ESH)
PD Dr. M. Clemens, Helmut-Schmidt-Universitat Hamburg, FB Elektrotechnik:
Simulation elektromagnetischer Felder mit diskreten Feldformulierungen: Theorische Modelle und praktische Anwendungen
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 06.09.2004, 17:00 (WIAS-ESH)
Dr. A. Erdmann, Fraunhofer IISB Erlangen:
Simulation photolithographischer Prozesse - Grundlagen, Anwendungspotential und Herausforderungen
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides
Monday, 05.07.2004, 17:00 (WIAS-ESH)
Prof. Dr. R. Klein, Potsdam Institut für Klimafolgenforschung (PIK):
Mathematische Modellierung im Kontext der Klimafolgenforschung
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Further Informations
Presentation slides

 


Contact: Dr. Torsten Köhler, Tel.: +49 30 20372-582