@article{OrzadaMaderwaldPoseretal.2012, author = {Orzada, S. and Maderwald, S. and Poser, B. A. and Johst, S. and Kannengiesser, S. and Ladd, M. E. and Bitz, Andreas}, title = {Time-interleaved acquisition of modes: an analysis of SAR and image contrast implications}, series = {Magnetic Resonance in Medicine}, volume = {67}, journal = {Magnetic Resonance in Medicine}, number = {4}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2594}, doi = {10.1002/mrm.23081}, pages = {1033 -- 1041}, year = {2012}, abstract = {s the magnetic field strength and therefore the operational frequency in MRI are increased, the radiofrequency wavelength approaches the size of the human head/body, resulting in wave effects which cause signal decreases and dropouts. Especially, whole-body imaging at 7 T and higher is therefore challenging. Recently, an acquisition scheme called time-interleaved acquisition of modes has been proposed to tackle the inhomogeneity problems in high-field MRI. The basic premise is to excite two (or more) different Burn:x-wiley:07403194:media:MRM23081:tex2gif-stack-1 modes using static radiofrequency shimming in an interleaved acquisition, where the complementary radiofrequency patterns of the two modes can be exploited to improve overall signal homogeneity. In this work, the impact of time-interleaved acquisition of mode on image contrast as well as on time-averaged specific absorption rate is addressed in detail. Time-interleaved acquisition of mode is superior in Burn:x-wiley:07403194:media:MRM23081:tex2gif-stack-2 homogeneity compared with conventional radiofrequency shimming while being highly specific absorption rate efficient. Time-interleaved acquisition of modes can enable almost homogeneous high-field imaging throughout the entire field of view in PD, T2, and T2*-weighted imaging and, if a specified homogeneity criterion is met, in T1-weighted imaging as well.}, language = {en} } @phdthesis{Bragard2012, author = {Bragard, Michael}, title = {The integrated emitter turn-off thyristor : an innovative MOS-gated high-power device. - (Aachener Beitr{\"a}ge des ISEA ; 62)}, publisher = {Shaker}, address = {Aachen}, isbn = {978-3-8440-1152-4}, pages = {III, 164 S. : Ill., graph. Darst.}, year = {2012}, abstract = {This thesis introduces the Integrated Emitter Turn-Off (IETO) Thyristor as a new high-power device. Known state-of-the-art research activities like the Dual GCT, the ETO thyristor and the ICT were presented and critically reviewed. A comparison with commercialized solutions identifies the pros and cons of each type of device family. Based on this analysis, the IETO structure is proposed, covering most benefits of each device class. In particular the combination of a MOS-assisted turn-off with a thyristor-based device allows a voltage-controlled MOS switching and the low on-state voltage of the thyristors. The following synthesis of an IETO device stands on a three-dimensional field of optimization spanned by electric, mechanical and thermal aspects. From an electric point of view, the lowest possible parasitic inductance and resistance within the commutation path are optimization criteria. The mechanical construction has to withstand the required contact pressure of multiple kilo Newtons. Finally, thermal borders limit the maximum average current of the device. FEM simulations covering these three aspects are performed for several design proposals. An IETO prototype is constructed and measurements on various test benches attest thermal, mechanical and electric performance. A local decoupling of the external driver stage and the presspack housing is presented by a cable connection. This separation enables a thermal and mechanical independence, which is advantageous in terms of vibrations and thermal cycles including increased reliability. The electric pulse performance of the prototype device is a factor of 3.1 above today''s solutions. In single-pulse measurements, a current up to 1600 A was successfully turned off at 115°C with an active silicon area of 823 mm². One reason for this increased turn-off capability is the extremely low-inductive construction. Additional functionality of the IETO thyristor like over-current self-protection and defined short-circuit failure state are successfully verified.}, language = {en} } @article{SchubaHoefkenSchaefer2012, author = {Schuba, Marko and H{\"o}fken, H. and Schaefer, T.}, title = {Smartphone Forensik}, series = {Hakin9 : Practical Protection (2012)}, journal = {Hakin9 : Practical Protection (2012)}, publisher = {-}, isbn = {1733-7186}, pages = {10 -- 20}, year = {2012}, language = {de} } @inproceedings{FeuerriegelPookWerschetal.2012, author = {Feuerriegel, Uwe and Pook, Michael and Wersch, Gregor and Wittenhorst, Simon and Becker, J{\"u}rgen and Ecker, Markus and Hoffmann, Ulrich and Kunz, Ulrich}, title = {Simulation von W{\"a}rme{\"u}bertragungsprozessen}, year = {2012}, abstract = {Mit freundlicher Genehmigung der Autoren und des Oldenbourg Industrieverlags https://www.oldenbourg-industrieverlag.de/de/9783835633223-33223 erschienen als Beitrag im Tagungsband zur AALE-Tagung 2012. 9. Fachkonferenz 4.-5. Mai 2012, Aachen, Fachhochschule. ISBN 9783835633223 S 5-1 S. 127-135 Es werden Ergebnisse unterschiedlicher Projekte aus dem Bereich der Simulation von W{\"a}rme{\"u}bertragungsprozessen mit Excel-VBA vorgestellt. - Thermische Behandlung hochviskoser Fruchtzubereitungen, verschiedene Projekte und Kooperationen mit der Zentis GmbH \& Co. KG, Aachen (J. Becker, U. Feuerriegel, G. Wersch). - Untersuchung des dynamischen Verhaltens von dampfbeheizten Ethylen-Verdampfern. Projekt mit der TGE Gas Engineering GmbH, Bonn (M. Ecker, U. Feuerriegel, U. Hoffmann, S. Wittenhorst). - Dynamische Simulation des axialen Temperaturverlaufs von elektrisch beheizten Rohrreaktoren. Kooperation mit dem Institut f{\"u}r Chemische Verfahrenstechnik, TU Clausthal (U. Feuerriegel, U. Kunz, M. Pook, S. Wittenhorst).}, subject = {W{\"a}rme{\"u}bertragung}, language = {de} } @inproceedings{LogenHoefkenSchuba2012, author = {Logen, Steffen and H{\"o}fken, Hans and Schuba, Marko}, title = {Simplifying RAM Forensics : A GUI and Extensions for the Volatility Framework}, series = {2012 Seventh International Conference on Availability, Reliability and Security (ARES), 20-24 August 2012, Prague, Czech Republic}, booktitle = {2012 Seventh International Conference on Availability, Reliability and Security (ARES), 20-24 August 2012, Prague, Czech Republic}, publisher = {IEEE}, address = {New York}, isbn = {978-1-4673-2244-7}, doi = {10.1109/ARES.2012.12}, pages = {620 -- 624}, year = {2012}, abstract = {The Volatility Framework is a collection of tools for the analysis of computer RAM. The framework offers a multitude of analysis options and is used by many investigators worldwide. Volatility currently comes with a command line interface only, which might be a hinderer for some investigators to use the tool. In this paper we present a GUI and extensions for the Volatility Framework, which on the one hand simplify the usage of the tool and on the other hand offer additional functionality like storage of results in a database, shortcuts for long Volatility Framework command sequences, and entirely new commands based on correlation of data stored in the database.}, language = {en} } @inproceedings{EngelsSchnabel2012, author = {Engels, Elmar and Schnabel, Holger}, title = {Rapid-control-prototyping of industrial drives for the sercos automation bus}, series = {13th International Workshop on Mechatronics (MECATRONICS), 2012 9th France-Japan \& 7th Europe-Asia Congress on and Research and Education in Mechatronics (REM)}, booktitle = {13th International Workshop on Mechatronics (MECATRONICS), 2012 9th France-Japan \& 7th Europe-Asia Congress on and Research and Education in Mechatronics (REM)}, isbn = {978-1-4673-4771-6}, pages = {177 -- 181}, year = {2012}, abstract = {This article describes the functionality of a MATLAB® library that can be used to develop motion-logic applications in MATLAB programming language for industrial drive and control systems using the well known sercos automation bus. Therewith MATLAB's functionality is extended to designing automation applications from single axis machines up to multi-kinematic robots.}, language = {en} } @incollection{Huening2012, author = {H{\"u}ning, Felix}, title = {PowerMOSFETs f{\"u}r Elektromotoren im Automobil : Vom Fensterheber zum EPS}, series = {Elektronik im Kraftfahrzeug : Innovationen bei Systemen und Komponenten ; mit 7 Tabellen}, booktitle = {Elektronik im Kraftfahrzeug : Innovationen bei Systemen und Komponenten ; mit 7 Tabellen}, editor = {Schmitz, G{\"u}nter}, publisher = {Expert Verlag}, address = {Renningen}, isbn = {978-3-8169-3110-2}, pages = {71 -- 81}, year = {2012}, language = {de} } @misc{FrauenrathNiendorf2012, author = {Frauenrath, Tobias and Niendorf, Thoralf}, title = {MRT-Vorrichtung und Verfahren zum Betreiben einer MRT-Vorrichtung}, year = {2012}, abstract = {A magnetic resonance tomography (MRT) apparatus (1) for the examination of a body (14) comprises parameter acquisition devices (13) for the acquisition of cardiovascular parameters of the body (14) and a control device (15) in communication with the parameter acquisition devices (13) for synchronizing the imaging, wherein the control device (15) is adapted to analyse the data of at least two parameter acquisition devices (13) and to output a control signal based on the analysis.}, language = {de} } @misc{FrauenrathPfeifferHezeletal.2012, author = {Frauenrath, Tobias and Pfeiffer, Harald and Hezel, Fabian and Dieringer, Matthias A. and Winter, Lukas and Gr{\"a}ßl, Andreas and Santoro, Davide and {\"O}zerdem, Celal and Renz, Wolfgang and Greiser, Andreas and Niendorf, Thoralf}, title = {Lessons learned from cardiac MRI at 7.0 T: LV function assessment at 3.0 T using local multi-channel transceiver coil arrays}, series = {2012 ISMRM Annual Meeting Proceedings}, journal = {2012 ISMRM Annual Meeting Proceedings}, issn = {1545-4428}, year = {2012}, abstract = {Cardiac MR (CMR) is of proven clinical value but also an area of vigorous ongoing research since image quality is not always exclusively defined by signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Recent developments of CMR at 7.0 T have been driven by pioneering explorations into novel multichannel transmit and receive coil array technology to tackle the challenges B1+-field inhomogeneities, to offset specific-absorption rate (SAR) constraints and to reduce banding artifacts in SSFP imaging. For this study, recognition of the benefits and performance of local surface Tx/Rx-array structures recently established at 7.0 T inspired migration to 3.0 T, where RF inhomogeneities and SAR limitations encountered in routine clinical CMR, though somewhat reduced versus the 7.0 T situation, remain significant. For all these reasons, this study was designed to build and examine the feasibility of a local four channel Tx/Rx cardiac coil array for anatomical and functional cardiac imaging at 3.0 T. For comparison, a homebuilt 4 channel Rx cardiac coil array exhibiting the same geometry as the Tx/Rx coil and a Rx surface coil array were used.}, language = {en} } @inproceedings{NoetzoldUphuesWegeneretal.2012, author = {N{\"o}tzold, K. and Uphues, A. and Wegener, R. and Soter, S. and Fink, K. and Bragard, Michael and Griessel, R.}, title = {Inverter based test setup for LVRT verification of a full-scale 2 MW wind power converter}, series = {EPE Joint Wind Energy and T\&D Chapters Seminar : 28th and 29th of June 2012, in the Utzon Centre, Aalborg, Denmark ; papers, posters, presentations. - Session 2: Grid connection, compliance}, booktitle = {EPE Joint Wind Energy and T\&D Chapters Seminar : 28th and 29th of June 2012, in the Utzon Centre, Aalborg, Denmark ; papers, posters, presentations. - Session 2: Grid connection, compliance}, publisher = {EPE Association}, address = {Brussels}, year = {2012}, language = {en} }