Fakultätskolloquium der Technischen Fakultät im SS 2016

  • Die Kolloquien an den Instituten für Elektrotechnik und Informationstechnik sowie Materialwissenschaften:

Jeweils montags eine halbe Stunde vor Beginn der Vorträge, also um 16.45 Uhr, werden die Gastredner den Besuchern des Kolloquiums in einer zwanglosen Runde bei einer Tasse Kaffee in der "Eisdiele" (Eingangshalle Geb. D, neben dem "Aquarium") vorgestellt.

Ansprechpartnerin:  Tanja Wengler  (Tel. 0431-880-6001) dekanat@tf.uni-kiel.de

                                    Jolanta Makowski (Tel. 0431-880-6068) dekanat@tf.uni-kiel.de

  • Die Kolloquien am Institut für Informatik:

Alle Vorträge finden - soweit nicht anders angegeben - im Raum Ü2/K des Instituts für Informatik (Ludewig-Meyn-Str. 2, Vorbau des Mathematischen Seminars) freitags um 14 Uhr c.t. statt. 45 Minuten vor Vortragsbeginn stehen Tee und Kaffee bereit.

Ansprechpartner/innen: Geschäftszimmer des Instituts für Informatik (Tel. 0431 880-4465)aktuell@informatik.uni-kiel.de

 

  • Wenn Sie die Einladungen per E-Mail erhalten möchten tragen Sie sich bitte in die Mailingliste ein.


Nachfolgend alle Vortragstermine in chronologischer Abfolge

Kolloquium Prof. Dr. Andreas Taubert, Universität Potsdam / 11.04.2016

11.04.2016 von 17:15 bis 18:45

Institut für Materialwissenschaft, Raum: Geb. D, Aquarium, Kaiserstraße 2, 24143 Kiel

Titel: Biomimetic calcium phosphate mineralization - effects of surfaces and interfaces

Abstract:

Calcium phosphate is one of the most important biominerals. It comes in a variety of phases, e.g. hydroxyapatite, brushite, etc., and is a key component in bones, teeth, and tendons.1,2 Biomimetic calcium phosphate mineralization, that is, the synthesis of calcium phosphate/organic composites using a synthetic template or additive, provides access to a large variety of calcium phosphate composites that could for instance be useful for bone repair. However, the details of calcium phosphate nucleation, growth, and phase selection are not fully understood yet. To rationally design tailored materials for specific applications such as healthcare, this would however be essential.Among others, interfaces are a key factor affecting the formation, structure, composition, and properties of both the calcium phosphate deposits and the resulting hybrid materials. In spite of this, there are only relatively few studies on the role of surfaces and interfaces on calcium phosphate growth.The presentation will present data on calcium phosphate formation on model surfaces, both at the solid-liquid3 and the liquid-air interface,4-7 and discuss the effects of these interfaces on crystal formation. A special focus is put on the effects of polycations, such as poly(2-dimethylethylamino methacrylate) (PDMAEMA), because polycations have been less extensively studied than polyanions and there is hence a lack of information on their role in calcium phosphate mineralization. This also applies to the effects of oligomeric compounds as mineralization templates.8 Our studies show that not only the type of surface (anionic vs. cationic) but also the charge of each polymer surface (charged vs. uncharged) strongly affects the outcome of the mineralization process. A preliminary hypothesis of how polycations may regulate calcium phosphate is also proposed9 and – time permitting – I will also present some recent data on how ionic liquids can be used to generate interesting composite materials.10

 

References

(1)       Calcium Phosphates in Biological and Industrial Systems; Kluwer Academic Publishers: Norwell-Dordrecht, 1998.

(2)       Handbook of Biomineralization; Wiley-VCH: Weinheim, 2007.

(3)       Löbbicke, R.; Chanana, M.; Schlaad, H.; Pilz-Allen, C.; Günter, C.; Möhwald, H.; Taubert, A. Biomacromolecules 2011, 12, 3753.

(4)       Casse, O.; Colombani, O.; Kita-Tokarczyk, K.; Müller, A. H. E.; Meier, W.; Taubert, A. Faraday Discuss. 2008, 139, 179.

(5)       Junginger, M.; Bleek, K.; Kita-Tokarczyk, K.; Reiche, J.; Shkilnyy, A.; Schacher, F.; Müller, A. H. E.; Taubert Nanoscale 2010, 2, 2440.

(6)       Junginger, M.; Kita-Tokarczyk, K.; Schuster, T.; Reiche, J.; Schacher, F. A.; Müller, A. H. E.; Cölfen, H.; Taubert, A. Macromol. Biosci. 2010, 10, 1084.

 (7)       Junginger, M.; Kübel, C.; Schacher, F. H.; Müller, A. H. E.; Taubert, A. RSC Adv. 2013, 3, 11301.

 (8)       Hentrich, D.; Junginger, M.; Bruns, M.; Börner, H. G.; Brandt, J.; Brezesinski, G.; Taubert, A. Cryst. Eng. Comm. 2015, DOI: 10.1039/C4CE02274B

 (9)       Shkilnyy, A.; Schöne, S.; Rumplasch, C.; Uhlmann, A.; Hedderich, A.; Taubert, A. Colloid Polym. Sci. 2011, 289, 881.

(10)     Salama, A.; Neumann, M.; Günter, C.; Taubert, A. Beilstein. J. Nanotechnol. 2014, 5, 1553.

 

Prof. Selhuber-Unkel

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Kolloquiumsvortrag, Prof. Dr. Joachim Biskup, TU Dortmund, Fakultät für Informatik / 22.04.2016

22.04.2016 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Publishing Inference-Proof Relational Data: Design, Implementation, Optimization and Experiments

Abstract:

An agent might want to share information maintained by a relational database by means of data publishing, i.e., by generating a view customized for the further unrestricted usage by the anticipated clients. Often, however, the usability of the view has to be confined to ensure the confidentiality of particular pieces of information in need of being excluded from sharing. Within the framework of Controlled Interaction Execution, we have designed a sound and complete generation procedure for an inference-proof (i.e., consistent and confidentiality-preserving) view that has minimal distortion distance to the original database instance. Confidentiality is achieved regarding a policy declared in terms of first-order logic sentences to be kept hidden. Consistency ensures the compliance with postulated a priori knowledge of the clients, expressed as first-order logic sentences, too. Conceptually, the generation procedure performs a depth-first search for satisfying the constraints and follows a branch-and-bound strategy for minimizing distortions. We have further provided an actual implementation of the generation procedure together with several optimizations. In particular, we exploited sophisticated local lower bounds on the number of additional distortions in subtrees to be explored to prune them early, and we employed coordinated parallelization for searching in many subtrees concurrently. Moreover, we have performed an experimental evaluation in terms of runtime behavior. Finally, we have also explored to replace depth-first searching by priority searching, exhibited special cases that can be handled more efficiently, considered heuristics for only approximating distortion minimality, and explored options of refined mechanisms to employ and invent constants to resolve current violations of constraints.
The original design was joint work with Lena Wiese (J. Biskup/L. Wiese, Journal of Computer Security 16 (2008) 477–494; L. Wiese, Dissertation, TU Dortmund 2009; J. Biskup, L. Wiese, Theoretical Computer Science 412 (2011) 4044–4072).
The implementation, the optimizations and the evaluation are joint work with Christine Dahn, Katharina Diekmann, Ralf Menzel, Dirk Schalge und Lena Wiese (manuscript submitted for publication).

Prof. Thalheim

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Kolloquiumsvortrag, Dr. Otwin Breitenstein, Max-Planck-Institut für Mikrostrukturphysik in Halle / 02.05.2016

02.05.2016 von 17:15 bis 18:45

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel: "Lock-in Thermography -- A Universal Tool for Evaluating Electronic Devices and Materials"

Abstract:

Lock-in Thermography (LIT) is a special variant of the well-known infrared thermography method, which uses a thermocamera detecting light in the thermal radiation range (typically 3 - 5 µm). The camera is connected to a computer, which switches certain power dissipation (heat) sources in the imaged object periodically on and off at a certain frequency. The incoming images are evaluated according to the lock-in principle, which is equivalent to connecting each image pixel to a lock-in amplifier. The primary result of a LIT measurement are the temperature modulation amplitude image and the phase image, which is a measure of the time delay of the surface temperature modulation with respect to the power modulation. Advantages of LIT compared to conventional (steady-state) thermography are a drastically improved sensitivity due to its averaging nature and a suppression of the lateral heat diffusion due to its dynamic nature.

In this talk the realization of LIT will be explained and a number of applications will be reported. Since the modulated heat sources in the investigated object can be of very different nature, LIT may be applied to study a lot of different physical problems. This talk reports on the application of LIT to non-destructive evaluation (looking below the surface of bodies), local efficiency analysis of solar cells, measurement of Peltier coefficients, failure analysis of integrated circuits, imaging of water adsorption in biological specimens, and investigation of spin-caloritronic effects in magnetic materials.

Prof. Adelung

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Sonderkolloquium Dr. Alzola /13.05.2016

13.05.2016 von 11:00 bis 12:00

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel: "Design and resonance-damping of LCL-filter based grid-tie converters and recent developments on power electronics control"

Abstract - The first part of the lecture will deal with LCL-filter based three-phase grid-tie converters. Adopting an LCL-filter, instead of an L-filter, allows using a reduced value for the total inductance and so reducing losses and preserving dynamics. However, stability problems can arise if the present resonance is not properly damped. Passive damping uses additional resistors and active damping modifies the control algorithm. Many solutions have been proposed in a vast amount of publications. For this lecture, different configurations for passive damping will be explained along with the following active damping procedures: lead-lag network, capacitor-current feedback and notch filter. Stability and robust design against grid line inductance variations will also be considered. The last part of the lecture explores the opportunity of harmonic mitigation at distribution level in small hybrid ac/dc building by using a centralized power factor corrector (PFC) with large bandwidth. It is foreseeable an increased presence of hybrid ac/dc buildings with coexisting ac and dc infrastructures because of the unprecedented expansion of native dc powered equipment (LEDs and consumer electronics). The proposals provide all the steps for the straightforward control design of the PFC and its harmonic mitigation function (HMF) with fast calculations. The HMF requires only software modifications in the PFC and one sensor to measure the nonlinear load.

 

Prof. Liserre

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Doppelkolloquiumsvortrag, Prof. Dr. Stefan Sauter, Universität Zürich / 27.05.2016, 14:15 - 16:00 Uhr

27.05.2016 von 14:15 bis 16:00

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Title: A Posteriori Error Majorant for Elliptic Partial Differential Equations with Applications to Homogenization.

Abstract:  In our talk, we will present new two-sided estimates of modeling errors for linear elliptic boundary value problems with periodic coefficients solved by homogenization method. Our approach is based on the concept of functional a posteriori error estimation. The estimates are obtained for the energy norm and use solely the global flux of the non-oscillatory solution of the homogenized model and solutions of some cell problem. Numerical tests illustrate the efficiency of the estimates.

Prof. Börm

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Doppelkolloquiumsvortrag, Prof. Dr. Ulrich Meyer, Algorithm Engineering Group, Institute of Computer Science, Goethe University, Frankfurt / 27.05.2016, 16:15 - 17:30 Uhr

27.05.2016 von 16:15 bis 17:30

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Generating and Traversing Large Graphs in External-Memory

Abstract:

Large graphs arise naturally in many real world applica-
tions. The actual performance of simple RAM model algo-
rithms for traversing these graphs (stored in external mem-
ory) deviates significantly from their linear or near-linear
predicted performance because of the large number of I/Os
they incur. In order to alleviate the I/O bottleneck, many
external memory graph traversal algorithms have been de-
signed with provable worst-case guarantees. In the talk I
highlight some techniques used in the design and engineer-
ing of such algorithms and survey the state-of-the-art in
I/O-efficient graph traversal algorithms. I will also report
on recent work concerning the generation of massive scale
free networks under resource constraints.

 

Prof. Srivastav

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Kolloquiumsvortrag, Dr. Jörg Hübner, Technical University of Denmark / 30.05.2016

30.05.2016 von 17:15 bis 18:45

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel: Micro and Nano structuring of Silicon at DTU Danchip.

Abstract:  Etching of silicon is the basic technology step for a large variety of MEMS, NEMS and microfluidic applications. Even the fabrication of  large area nanostructure in polymere starts in our examples with lithography and etch of silicon. The talk will therefore after a short introduction to DTU Danchip focus on plasma etching of silicon. The plasma chemistry and physics during silicon etch poses challenges and opportunities, which will be using examples reaching from nanopillars for SERS enhancement to X-ray compound lenses. There will also be a short excursion into Atomic Layer Deposition and some results on structures realised with this very versatile technology.

 


 


Prof. Adelung

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Kolloquiumsvortrag, Prof. Partha Roop, Department of Electrical and Computer Engineering, University of Auckland / 03.06.2016

03.06.2016 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: The science of bio-remulation for Executable Organ on Chips

Abstact: 

The use of simulation models in biology is extensively studied. Emulation is used, in contrast to simulation, when a controller (such as a pacemaker) for a biological process (the heart) needs validation in real-time. Here, the pacemaker is connected in closed-loop with a living heart. This may occur either during the clinical trial phase with human subjects or animal models. We argue that such emulation is expensive, time limiting, and has associated ethical considerations. We propose the science of remulation (reverse-emulation) as an alternative paradigm. Here, we develop executable models of the biological process (say the cardiac conduction system) that is realisable on a reprogrammable computer chip.

Such an ``Executable Organ on Chip'' (ExOoC) provides high-fidelity and real-time capabilities like a real heart, from the point of view of the pacemaker. Remulation of such ``Executable Organ on Chip'' (ExOoC) has not only excellent potential for medical device validation and certification but also can be used for personalisation and
non-invasive diagnostics. We have developed the first high-fidelity remulation model of the cardiac conduction system and have used this to validate a pacemaker in real-time.

Prof. Dr. Reinhard von Hanxleden

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Sonderkolloquium am 09.06.2016, Prof. Yoav Y. Schechner, Technion, Haifa, Israel / Vortrag im Rahmen der Schleswig-Holsteinischen Bildverarbeitungstage

09.06.2016 von 13:20 bis 14:00

Driftmann-Hörsaal, Olshausenstr. 75, Hörsaal 3

Titel: "The next best underwater view"

Abstract:  To image in high resolution large and occlusion-prone scenes, a camera must move above and around. Degradation of visibility due to geometric occlusions and distances is exacerbated by scattering underwater. Moreover, underwater and in other media, artificial lighting is needed. We propose to jointly optimize the path of platforms carrying either a camera or a light source. The work generalizes the next best view concept of robot vision to scattering media and cooperative movable lighting.

Prof. Koch

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Sonderkolloquium am 09.06.2016, Prof. Xiaoyi Jiang, Universität Münster / Vortrag im Rahmen der Schleswig-Holsteinischen Bildverarbeitungstage

09.06.2016 von 14:05 bis 14:50

Driftmann-Hörsaal, Olshausenstr. 75, Hörsaal 3

Titel: "Biomedical Imaging: Challenges and Chances for Computer Vision"

Abstract: With the widespread use of imaging technologies in basic research and routine clinical practice, medical researchers and physicians are faced with analyzing an ever-increasing amount of complex image data. Also in biology imaging has become an indispensable tool, for instance for behavior studies of small animals. Many computer vision algorithms have been successfully adapted and applied to biomedical imaging applications. However, the specific characteristics of biomedical image data pose new challenges and force researchers to develop novel concepts and algorithms. In fact, biomedical imaging can be seen as another driving force for computer vision research. This talk emphasizes this fundamental research view of biomedical computer vision. A variety of topics will be motivated by current research in biology and medicine. The related challenges, concepts, and algorithms will be discussed.


Prof. Koch

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Kolloquiumsvortrag, Prof. Richard James, University Minnesota USA / 20.06.2016

20.06.2016 von 17:15 bis 18:45

Institut für Materialwissenschaften, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel: Compatibility, hysteresis and the direct conversion of heat to electricity

Abstract: Big first order phase transformations in solids can be highly reversible, if the lattice parameters are “tuned” to satisfy certain relations that promote the compatibility between phases.  We outline the basic theory behind this tuning and give examples of recently discovered alloys.  Some of these alloys have thermal hysteresis as low as 0.2 C despite having an 8% transformation strain.   The lowered hysteresis correlates with the reversibility of the transformation under repeated cycling, and links to important discoveries madein Kiel.  We use this kind of tuning, together  with the lattice parameter sensitivity of magnetic properties and the presence of a jump of lattice parameters at the phase transformation, to find some interesting new multiferroic Heusler alloys: briefly, multiferroism by reversible phase transformation.  These alloys can be used in diverse ways for the direct conversion of heat to electricity, and provide interesting possible ways to recover the vast amounts of energy stored on earth at small temperature difference.

Prof. Quandt

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Kolloquiumsvortrag, Prof. Sudhir R. Ghorpade Department of Mathematics Indian Institute of Technology Bombay / am Donnerstag, 23.06.2016, 16:00 - 17:00 Uhr

23.06.2016 von 16:00 bis 17:00

Christian-Albrechts-Platz 4, Raum 910

Title:  Systems of polynomial equations over finite fields and linear codes

 

Abstract: 

 We consider the problem of determining the maximum number of common solutions of a bunch of polynomials over a finite field. The simplest case is of course of a single (nonzero) polynomial in one variable, where the degree usually gives the maximum number of solutions. In the general case of several polynomials in several variables, the problem is meaningful and interesting when the base field is finite and the solutions are sought in the corresponding affine or projective space over the given finite field. When these polynomials are assumed linearly independent and of a degree bounded by a fixed positive integer, the problem is equivalent to a problem in coding theory, namely, that of determining the generalized Hamming weights of Reed-Muller codes. The known solution in this case, due to Heijnen and Pellikaan (1998) uses results in combinatorics such as Kruskal-Katona theorem.

The case of systems of linearly independent multivariate homogeneous polynomials, all of the same degree, where the zeros are considered in a projective space over the given finite field is perhaps even more interesting. There is an elaborate conjecture of Tsfasman and Boguslavsky that predicts the maximum value when the degree of the homogeneous polynomials is not too large in comparison to the size of the finite field. Special cases of the conjecture are known to be true, thanks to the results of Serre (1991) and Boguslavsky (1997), but the general case has been open for quite some time.


We will give a motivated account of the above problem and its alternative formulations while briefly explaining the relevant background. We will then describe some recent developments that has led to significant new results concerning the general case. This is based mainly on a joint work with Mrinmoy Datta.
 

Prof. Andan Srivastav

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Kolloquiumsvortrag, Prof. Dr. Nikolai Axmacher, Institute of Cognitive Neuroscience, Department of Neuropsychologie, Ruhr University Bochum / 27.06.2016

27.06.2016 von 17:15 bis 18:45

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel:  Network mechanisms of memory representations in the human brain

Abstract:  How can the neural representations of specific experiences, or engrams, be identified in the human brain? Which neural properties determine the accuracy of memory traces, how are they altered in diseases that involve memory dysfunction, and can electric stimulation be used to restore them? In this talk, I will describe the neural mechanisms supporting content-specific representations in perception and memory, and how these findings shed light on early disease processes and may help developing new therapeutic approaches.

In the first part of the talk, I will present our basic framework for studying network representations in the human brain. In particular, analyzing brain oscillations and oscillatory interactions allows us to characterize regional activation patterns and mechanisms supporting inter-regional communication and plasticity. In the second part, I will describe some recent studies on network representations of memory traces. Using intracranial EEG recordings in epilepsy patients as well as simultaneous EEG/fMRI recordings in healthy participants, we found that stimulus-specific representations are reinstantiated during memory recall and spontaneously reactivated during awake resting state and sleep. As I will show in the third part, analyzing content-specific representations may be clinically relevant to identify early pathophysiology and potential new therapies in Alzheimer’s dementia. Using fMRI in genetic risk carriers for Alzheimer’s disease, we observed impaired entorhinal grid cell-like representations and altered navigational strategies. Furthermore, we found that deep brain stimulation to the medial temporal lobe may be a novel therapeutic option for ameliorating memory dysfunction; understanding the oscillatory basis of memory processes may help optimizing stimulation parameters.

Prof. Kohlstedt

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Sonderkolloquium, Prof. Dr. Olaf Landsiedel, Chalmers University of Technology, Göteborg / 28.06.2016, 14:30 - 15:30 Uhr

28.06.2016 von 14:30 bis 15:30

Christian-Albrechts-Platz 4, Raum 1304 a

Titel: Chaos: Versatile and Efficient All-to-All Data Sharing and In-Network Processing at Scale

Abstract: An important building block for low-power wireless systems is to efficiently share and process data among all devices in a network. We introduce Chaos, a primitive that natively supports all-to-all data sharing in low-power wireless networks. Different from current approaches, Chaos embeds programmable in-network processing into a communication support based on synchronous transmissions. We show that this design enables a variety of common all-to-all interactions, including network-wide agreement and data aggregation. Chaos scales efficiently to networks consisting of hundreds of nodes, achieving severalfold improvements over the state of the art in radio duty cycle and latency at high reliability. For example, Chaos computes simple aggregates, such as the maximum, in a 100-node multi-hop network within less than 90 milliseconds using off-the-shelf IEEE 802.15.4 radios.
Moreover, Chaos departs from the traditional message-based programming paradigm of networking and utilizes an approach that is similar to shared memory: Nodes maintain local state which they merge with any received state and which they in-turn share with neighboring nodes. We discuss how this paradigm changes protocol design and implementation. For example, we show how Chaos can provide widespread communication patterns such as collection, dissemination, agreement, and aggregation at high performance and low implementation complexity.

 

Prof. Dr. Thomas Wilke

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Kolloquiumsvortrag, Prof. Nini Pryds, Departement for Energy Conversion and Storage, Technical University of Denmark / 04.07.2016

04.07.2016 von 17:15 bis 18:45

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"


Titel: "Highly Efficient Caloric Devices"

Abstract: The demand for high cooling power devices with a high efficiency is a challenge for the appliance market. An increasing number of novel caloric devices have been presented recently. The results and performance are continually improving, but the efficiency of these devices is still too low to allow the technology to break though commercially. At DTU Energy we have developed and tested several high performance Calorics devices. I will present our past and present activities related to designing magnetic refrigeration devices and in particular I will describe and show the recent results obtained with MAGGIE. Furthermore, in this talk we will present a new elastocaloric cooling system based on the active regeneration principle. Such a system is analogue to the active magnetic regenerator. The system development, its operational principle and the preliminary results (the temperature span and cooling power at different operating conditions) will be also presented and discussed.

 

 

Prof. Quandt

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Kolloquiumsvortrag, Dr. Sebastian Wintz, Paul Scherrer Institute Villingen, Switzerland / 11.07.2016

11.07.2016 von 17:15 bis 18:45

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel: "Topological Spin Textures as Spin Wave Emitters"

Abstract:

Today, spin waves are seen as high potential information carrier for next-generation information and communication devices [1]. This view is based on the substantially reduced energy dissipation and much smaller wavelengths of spin waves compared to traditional charge current signals. For the implementation of spin wave technology into applicable devices, however, novel concepts for the generation, manipulation, and detection of spin waves are yet to be found. With respect to spin wave generation, it was typically necessary to either use patterned transducers with sizes on the order of the desired wavelengths (striplines or point-contacts), or to generate those spin waves parametrically by a double-frequency spatially uniform microwave signal [2]. In this presentation, I will report on a newly discovered concept for the generation of spin waves, which overcomes the bandwidth limitations in terms of the minimum wavelength limit given by the patterning size. This method utilizes the translation of natural topological defects, namely the gyration of magnetic vortex cores to generate isotropically propagating,  non-reciprocal  spin  waves  [3].  Experimentally,  such  spin-waves  were directly  observed  by  means  of  time-resolved x-ray  microscopy. Furthermore, I  will address directional and one-dimensional spin wave emission in anistropic magnetic systems.

[1] D. Rosso, “International Technology Roadmap for Semiconductors Explores Next 15

Years of Chip Technology”, www.semiconductors.org, (2014).

[2] A. G. Gurevich and G. A. Melkov, Magnetization Oscillations and Waves. New York: CRC, 1996.

[3] S. Wintz et al., submitted (2015).

Today, spin waves are seen as high potential information carrier for next-generation information and  communication devices.  This  is  based  on  the  substantially reduced energy dissipation and much smaller wavelengths of spin waves compared to traditional charge current signals. For a device implementation, however, novel concepts for the generation, manipulation, and detection of spin waves are yet to be found. Here, we report on a newly discovered concept for the generation of spin waves, which overcomes typical bandwidth limitations of traditional spin wave excitation methods. Our approach utilizes the  gyration  of  magnetic  vortex  cores  to  generate  isotropically  propagating,  non- reciprocal spin waves.

 

Prof. McCord

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Sonderkolloquium, Dr. Alex Q. Huang, North Carolina State University / 09.09.2016

09.09.2016 von 09:30 bis 11:00

Institut für Elektrotechnik, Kaiserstraße 2, 24143 Kiel, Geb. D, "Aquarium"

Titel: 15 kV SiC MOSFET Based Medium Voltage DC/DC Converter

 

Abstract: Medium voltage DC-DC converter is an important element of a medium voltage solid state transformer (SST). It is also considered the most critical element in the future medium voltage DC grid. In reaching medium voltage operation range, device series connection and converter series connection are all viable solutions. This talk will discuss the unique capability of SiC MOSFET in achieving extremely simple and high power density design by operating at very high switching frequency. This is achieved by taking advantage of the zero switching loss in ZVS-based converters and design optimization. Control strategies to improve the reliability of the DC/DC converter is also discussed. In conclusion, 15 kV SiC MOSFET is almost an ideal semiconductor switch that can enable medium voltage conversion at 100 kHz and at a voltage up to 12 kV.

 

Dr. Alex Q. Huang

Dr. Alex Huang received his B.Sc. degree from Zhejiang University, China in 1983 and his M.Sc. degree from Chegdu Institute of Radio Engineering, China in 1986, both in electrical engineering. He received his Ph.D. from Cambridge University, UK in 1992. From 1994 to 2004, he was a founding member and a professor of Center for Power Electronics System (an NSF ERC) at Virginia Tech. Since 2004, he has been a professor of electrical engineering at North Carolina State University and he is currently the Progress Energy Distinguished Professor of Electrical and Computer Engineering. He established the NSF FREEDM Systems ERC in 2008. As part of the FREEDM System concept, he developed the original concept of Energy Internet with the Solid State Transformer serving as an Energy Router. Today, FREEDM Systems ERC is one of the most successful ERCs in the USA with support from many companies. Dr. Huang is also the lead PI and visionary leader behind NCSU’s recent success in establishing the next generation Wide bandgap power electronics manufacturing innovation institute.

Dr. Huang’s research areas are power semiconductor devices, power management integrated circuits, power electronics and its emerging applications such as those in future electric power delivery and management systems. A very active and productive research leader, Dr. Huang has mentored and graduated more than 70 Ph.D. and master students and has generated more than $200m external R&D fundings in the last 20 years.  Dr. Huang has published more than 450 papers in journals and conference proceedings, and holds 20 US patents.  Dr. Huang is the inventor and developer of the ETO thyristor technology. Dr. Huang is a fellow of IEEE and the recipient of the prestigious 2003 R&D 100 award and 2011 MIT Technology Magazine awards. 

 

Prof. Dr. Marco Liserre

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