@article{ReutherSteffens, author = {Reuther, Maike and Steffens, Oliver}, title = {Evaluation der Bauteiltemperierung f{\"u}r den Herzogskasten Abensberg}, series = {Bauphysik}, volume = {37}, journal = {Bauphysik}, number = {2}, publisher = {Ernst \& Sohn, a Wiley Brand}, doi = {10.1002/bapi.201510010}, pages = {96 -- 99}, abstract = {Die These, dass die Methode der direkten Temperierung von erdber{\"u}hrten oder anderweitig feuchtebelasteten Bauteilen zur Beseitigung von Feuchtesch{\"a}den in Bestandsgeb{\"a}uden auch die Energieeffizienz des Geb{\"a}udes erh{\"o}hen und sogar ohne weitere energetische Sanierungsmaßnahmen die Anforderungen der Energieeinsparverordnung (EnEV) erf{\"u}llen kann, wird anhand des als Museum genutzten Herzogskastens in Abensberg {\"u}berpr{\"u}ft. In Verbindung mit einer Evaluation der Trocknungswirkung wird die Geb{\"a}ude-Energieeffizienz durch Vergleich von Bedarfsberechnungen auf Basis der DIN V 18599 mit realen Verbrauchszahlen {\"u}berpr{\"u}ft und diskutiert.}, language = {de} } @techreport{SchlampEhrlich, author = {Schlamp, Matthias and Ehrlich, Ingo}, title = {Analyse des Impact-Verhaltens gekr{\"u}mmter Strukturbauteile von Luftfahrzeugen zur Entwicklung eines Struktur{\"u}berwachungssystems f{\"u}r faserverst{\"a}rkte Kunststoffe - BIRD}, series = {Forschung 2019 / Ostbayerische Technische Hochschule Regensburg}, journal = {Forschung 2019 / Ostbayerische Technische Hochschule Regensburg}, editor = {Baier, Wolfgang}, publisher = {VMK Verlag f{\"u}r Marketing \& Kommunikation GmbH \& Co. KG}, organization = {Ostbayerische Technische Hochschule Regensburg}, isbn = {978-3-9818209-6-6}, pages = {40 -- 41}, abstract = {Die in Flugvorausrichtung weisenden Bauteile von Luftfahrzeugen sind oftmals durch Einschl{\"a}ge aufgrund von Vogelschlag, Hagel oder aufgewirbelten Kleinteilen gef{\"a}hrdet. Diese Einschl{\"a}ge, sogenannte Impacts, weisen bei faserverst{\"a}rkten Kunststoffen ein stark kr{\"u}mmungs- und materialabh{\"a}ngiges Verhalten und Schadensausmaß auf. Impact-Sch{\"a}digungen f{\"u}hren oftmals zu hohen Reparaturkosten, welche durch eine genauere Kenntnis des Schadens verringert werden k{\"o}nnen. Zur Klassifizierung dieser Sch{\"a}digungen steht dabei vor allem das auftretende Frequenz signal des Impacts im Fokus der Untersuchungen.}, language = {de} } @article{RomanoMicklitzOlbrichetal., author = {Romano, Marco and Micklitz, Matthias and Olbrich, Florian and Bierl, Rudolf and Ehrlich, Ingo and Gebbeken, Norbert}, title = {Experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method}, series = {Journal of Achievements in Materials and Manufacturing Engineering}, volume = {63}, journal = {Journal of Achievements in Materials and Manufacturing Engineering}, number = {2}, pages = {65 -- 80}, abstract = {Purpose: of this paper is experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method. Design/methodology/approach: For the evaluation of the presumed effect experimental structural dynamic investigations comparing unidirectionally and fabric reinforced plastics are carried out. In detail the free decay behaviour of flat beamlike specimens under fixed-free boundary conditions and relatively constant and reproducible displacement excitation is investigated. Findings: The vibrating structure has been measured by a laser scanning vibrometer PSV 400 from POLYTEC. In both cases evaluation of the results yields enhanced damping properties of the specimens with fabric reinforcement compared to the unidirectionally reinforced specimens. The results justify the presumed acting of a mesomechanic kinematic. Research limitations/implications: The results show that in either case the material damping in terms of the logarithmic decrement of the fabric reinforced material is higher than the material damping in of the unidirectionally reinforced material. Additionally, when the fabric reinforced specimens are addressed, in each case the plain weave reinforced specimens exhibited higher values of the material damping as the twill weave 2/2 reinforced ones. Originality/value: Ondulations in fabrics as a textile semi-finished product are caused by the alternating crossing of warp and fill yarns. In the mesoscopic scale the acting of a mesomechanic kinematic is presumed to enhance the damping properties under cyclic elastic deformation. For the evaluation of the presumed effect experimental structural dynamic investigations comparing unidirectionally and fabric reinforced plastics are carried out.}, language = {en} } @inproceedings{JobstBierl, author = {Jobst, Simon and Bierl, Rudolf}, title = {A Comparison of Correlation and Zero-Crossing Based Techniques in Ultrasonic Measurement}, series = {10th International Symposium on Applied Reconfigurable Computing (ARC'2014), Vilamoura, Algarve, Portugal, 14 - 16 April, 2014}, booktitle = {10th International Symposium on Applied Reconfigurable Computing (ARC'2014), Vilamoura, Algarve, Portugal, 14 - 16 April, 2014}, abstract = {Ultrasound measurement technology has advancedin previous decades due to positive developments in computing power and lower cost for the necessary hardware. Correlation-based processing can be advantageous for high-accuracy measurements, especially in noisy environments. Higher computational load makes correlation less attractive for industrialapplications, though, favouring traditional processing techniques. A platform for comparing various processing techniques hasbeen developed. It was found that both zero-crossing detectionas well as correlation can achieve very high accuracy over a hightemperature range but that correlation-based processing can lead to a significant precision bias depending on system bandwidth.}, language = {en} } @inproceedings{HofmannBierlRueck, author = {Hofmann, Matthias and Bierl, Rudolf and R{\"u}ck, Thomas}, title = {Implementation of a dual-phase lock-in amplifier on a TMS320C5515 digital signal processor}, series = {Proceedings of the 5th European DSP Education and Research Conference (EDERC), 13-14 Sept. 2012, Amsterdam}, booktitle = {Proceedings of the 5th European DSP Education and Research Conference (EDERC), 13-14 Sept. 2012, Amsterdam}, doi = {10.1109/EDERC.2012.6532217}, abstract = {A digital dual-phase lock-in amplifier that is capable to run on a low-cost, low-power platform comprising a 16-bit fixed-point digital signal processor was developed. This is achieved by a set of optimised digital filters including an exponential averager to adjust the time constant of the overall filter. The reference frequency is generated using a direct digital synthesis source utilising angle decomposition with a resolution of 1 Hz. The digital lock-in algorithm is described and the performance of the algorithm is analysed. The experimental results show that the developed lock-in amplifier achieves similar performance to a commercially available lock-in amplifier.}, language = {en} } @inproceedings{RueckLandgrafLaeppleetal., author = {R{\"u}ck, Thomas and Landgraf, Ferdinand and L{\"a}pple, I. and Unger, J. and Matysik, Frank-Michael and Bierl, Rudolf}, title = {Specification of an improved photoacoustic setup for high-sensitive, low-cost NO2 trace gas detection}, series = {18th International Conference on Photoacoustic and Photothermal Phenomena (ICPPP18), 2015, September 6-10, Novi Sad, Serbia}, booktitle = {18th International Conference on Photoacoustic and Photothermal Phenomena (ICPPP18), 2015, September 6-10, Novi Sad, Serbia}, language = {en} } @inproceedings{vanderWeerdBierlMatysik, author = {van der Weerd, Bastiaan and Bierl, Rudolf and Matysik, Frank-Michael}, title = {A Conductivity Probe for the Determination of Carbon Dioxide Tension at the Oxygenator Exhaust Outlet during Extracorporeal Membrane Oxygenation (ECMO)}, series = {analytica Conference 2014, 1. bis 4. April, M{\"u}nchen}, booktitle = {analytica Conference 2014, 1. bis 4. April, M{\"u}nchen}, language = {en} } @inproceedings{vanderWeerdBierlMatysik, author = {van der Weerd, Bastiaan and Bierl, Rudolf and Matysik, Frank-Michael}, title = {A Conductivity Probe for the Determination of Carbon Dioxide Tension at the Oxygenator Exhaust Outlet during Extracorporeal Membrane Oxygenation (ECMO)}, series = {Electrochemistry 2014, September 22 - 24, Mainz}, booktitle = {Electrochemistry 2014, September 22 - 24, Mainz}, language = {en} } @inproceedings{vanderWeerdBierlMatysik, author = {van der Weerd, Bastiaan and Bierl, Rudolf and Matysik, Frank-Michael}, title = {A Planar Conductivity Probe for CO2 Determination at the Oxygenator Outlet}, series = {Doktorandenseminar GDCh Prozessanalytik 2014, Berlin}, booktitle = {Doktorandenseminar GDCh Prozessanalytik 2014, Berlin}, language = {en} } @inproceedings{TheussElianFinketal., author = {Theuss, Horst and Elian, Klaus and Fink, Markus and Fries, M. and Kalz, Franz-Peter and Schwabe, B. and Vaupel, M. and Jaroschek, C. and Schubert, A. and Hummel, H. and Steffens, Oliver}, title = {Mechanical Stress Impact of Assembly Processes onto a Stress-sensitive Testchip}, series = {44th International Symposium on Microelectronics (IMAPS 2011), October 9 - 13, 2011, Long Beach, California, USA}, booktitle = {44th International Symposium on Microelectronics (IMAPS 2011), October 9 - 13, 2011, Long Beach, California, USA}, number = {1}, publisher = {International Microelectronics \& Packaging}, address = {Washington}, isbn = {978-1-61839-850-5}, doi = {10.4071/isom-2011-WA5-Paper3}, pages = {619 -- 626}, abstract = {A semiconductor die typically undergoes a variety of assembly processes, each of them influencing the mechanical stress environment of the chip. We report on a stress-sensitive testchip and its application to measure and characterize the respective stress distributions across the die. Particularly in the field of MEMS and sensor devices, even low stresses might deteriorate the electrical performance of a device significantly, while higher stress levels may even cause cracks and irreversible damage. This is why the present methodology has a high potential to develop into a useful tool in the field of sensor package development. After a brief introduction to the sensing principle, we investigate the stress distribution in various sample assemblies - all of them targeting pressure sensors. Typical low stress packages use silicone based soft elastic encapsulations. Changing to a harder material with a young's modulus comparable to standard mold compounds, we demonstrate an increase of the average stress level by more than one order of magnitude.}, language = {en} } @article{MalzSteiningerDawoudetal., author = {Malz, Sebastian and Steininger, Peter and Dawoud, Belal and Krenkel, Walter and Steffens, Oliver}, title = {On the Development of a Building Insulation using Air Layers with Highly Reflective Interfaces}, series = {Energy and Buildings}, journal = {Energy and Buildings}, number = {236, April}, publisher = {Elsevier}, doi = {10.1016/j.enbuild.2021.110779}, abstract = {In this work, a novel building insulation system implying wooden fiberboards and intermediate air layers with highly reflective interfaces for the reflection of longwave IR radiation is introduced. A wall test sample with a double air insulation layer has been built and experimentally investigated in a dedicated setup, which consists of a differential climatic chamber to simulate different indoor and outdoor conditions. The test results have been utilized in validating the developed simulation model. In addition, a thorough numerical parameter study has been conducted, through which the general design rules of the introduced insulation system for realizing the lowest possible effective thermal conductivity have been defined. Furthermore, a multi-air-layer-insulation concept is developed, and the energy saving potential is evaluated. It turned out that, emissivity, object size and air layer thickness are the most dominant design parameters which influence the thermal conductivity of the introduced insulation. A thermal conductivity of 0.033 W/(mK) has been estimated for a multi-air-layer insulation with 7 layers. The obtained results prove the high insulation potential of the introduced building insulation system compared with insulating materials available in the market while outlining their limitations.}, language = {en} } @inproceedings{SteffensSzaboLenzetal., author = {Steffens, Oliver and Szab{\´o}, Peter and Lenz, Michael and Farkas, G{\´a}bor}, title = {Thermal transient characterization methodology for single-chip and stacked structures}, series = {Semiconductor Thermal Measurement and Management Symposium, 2005}, booktitle = {Semiconductor Thermal Measurement and Management Symposium, 2005}, publisher = {IEEE}, issn = {1065-2221}, doi = {10.1109/STHERM.2005.1412198}, pages = {313 -- 321}, abstract = {High-power semiconductor packages typically exhibit a 3D heat flow, resulting in large lateral changes in chip and case surface temperature. For single-chip devices we propose to use an unambiguous definition for the junction-to-case thermal resistance as a key parameter, based on a transient measurement technique with much higher repeatability, also for very low thermal resistances compared to a two-point thermal resistance measurement. The technique is illustrated on thermal transient measurements of power MOSFETs. A comparison between different thermal coupling to the ambient is used to demonstrate the method's capability to reveal even subtle internal details of the package. The concept is extended to multichip and stacked-chip structures, where transfer impedances have to be introduced. Here, the dynamic properties of the package are important and complex impedance mapping is the proper way to characterize the package.}, language = {en} } @article{PuffSeidelSteffens, author = {Puff, Simone and Seidel, Uwe M. and Steffens, Oliver}, title = {Pflege- und intensivmedizinische Bereiche im EnEV-Bewertungsverfahren}, series = {Bauphysik}, volume = {37}, journal = {Bauphysik}, number = {6}, doi = {10.1002/bapi.201510036}, pages = {307}, abstract = {Die Anwendbarkeit des derzeit g{\"u}ltigen Verfahrens zur energetischen Bewertung von Nichtwohngeb{\"a}uden gem{\"a}ß aktueller Energieeinsparverordnung (EnEV 2014) in Verbindung mit DIN V 18599 als Planungs- und Bewertungstool auf Pflege- und intensiv-medizinische Bereiche von Krankenh{\"a}usern wird an einem beispielhaften, mittelgroßen Krankenhaus untersucht. Der Fokus liegt dabei auf der Praktikabilit{\"a}t der Abbildung von thermischen Lasten und Raumzust{\"a}nden durch die Normnutzungsprofile aus DIN V 18599 Teil 10 im Vergleich zu realen, vor Ort erfassten Nutzungsbedingungen. Weitere Betrachtungen in einer einfachen thermischen Simulation (TRNSYSlite) erlauben eine methodische Kritik in Bezug auf die Aussagekraft der nach Norm berechneten EnEV-Ergebnisse. Es werden Empfehlungen f{\"u}r Maßnahmen zur Verbesserung der energetischen Performance und der Behaglichkeit in Krankenh{\"a}usern im Bereich der Planung erarbeitet.}, subject = {Energieeinsparungsverordnung}, language = {de} } @article{WensauerSteffensSuhrkeetal., author = {Wensauer, Andreas and Steffens, Oliver and Suhrke, Michael and R{\"o}ssler, Ulrich}, title = {Laterally coupled few-electron quantum dots}, series = {Physical Review B}, volume = {62}, journal = {Physical Review B}, number = {4}, doi = {10.1103/PhysRevB.62.2605}, pages = {2605}, abstract = {We present ground-state calculations for laterally coupled quantum dots containing 2, 4, and 8 electrons. As our emphasis is on spin effects our results are obtained by applying spin-density functional theory (SDFT). By varying the distance between the centers of the coupled quantum dots, the transition from weak to strong coupling situation is realized. For the 2-electron system we also apply the Heitler-London approximation and analytical concepts to check the reliability of SDFT calculations in this case. In addition we discuss the features of the Coulomb staircase of laterally coupled quantum dots in the weak and strong coupling regimes in comparison to that of a circular parabolic quantum dot.}, language = {en} } @inproceedings{Steffens, author = {Steffens, Oliver}, title = {"Gr{\"u}nes Denkmal" - Denkmalpflege und Erneuerbare Energien erg{\"a}nzen sich}, series = {Vorsicht Baudenkmal! Konfliktfelder Umwelt - Nutzung - Geschichte. Beitr{\"a}ge des 28. Regensburger Herbstsymposions f{\"u}r Kunst, Geschichte und Denkmalpflege vom 22. bis 24. November 2013}, booktitle = {Vorsicht Baudenkmal! Konfliktfelder Umwelt - Nutzung - Geschichte. Beitr{\"a}ge des 28. Regensburger Herbstsymposions f{\"u}r Kunst, Geschichte und Denkmalpflege vom 22. bis 24. November 2013}, editor = {Trapp, Eugen}, publisher = {Regensburg}, address = {Morsbach-Verl.}, isbn = {978-3-937527-77-2}, pages = {9 -- 17}, subject = {Denkmalpflege}, language = {de} } @inproceedings{SteffensSuhrkeRoessler, author = {Steffens, Oliver and Suhrke, Michael and R{\"o}ssler, Ulrich}, title = {Correlation in few-electron quantum dots: Spin effects and spontaneous currents}, series = {24rd International Conference on the Physics of Semiconductors (ICPS 24), Jerusalem, Israel, August 2-7, 1998}, booktitle = {24rd International Conference on the Physics of Semiconductors (ICPS 24), Jerusalem, Israel, August 2-7, 1998}, editor = {Gershoni, David}, publisher = {World Scientific}, address = {Singapore}, isbn = {978-981-02-3613-7}, language = {en} } @masterthesis{Gering, type = {Bachelor Thesis}, author = {Gering, Stefan}, title = {Thermische Detailsimulationen in der Bestandssanierung}, address = {Regensburg}, language = {de} } @article{SzaboSteffensLenzetal., author = {Szab{\´o}, Peter and Steffens, Oliver and Lenz, Michael and Farkas, G{\´a}bor}, title = {Transient junction-to-case thermal resistance measurement methodology of high accuracy and high repeatability}, series = {IEEE Transactions on Components and Packaging Technologies}, volume = {28}, journal = {IEEE Transactions on Components and Packaging Technologies}, number = {4}, issn = {1521-3331}, doi = {10.1109/TCAPT.2005.859768}, pages = {630 -- 636}, abstract = {High-power packages show a characteristic three-dimensional heat flow resulting in large lateral changes in chip and case surface temperature. This paper proposes an unambiguous definition for the R/sub thJC/ junction-to-case thermal resistance as a key parameter of such packages based on a transient measurement technique ensuring high repeatability even at very low R/sub th/ values. The technique is illustrated on thermal transient measurements of high-power MOSFET devices. It is also presented how the same measurement results can be used for die attach quality analysis. Finally, a comparative method is shown for measuring the differences of R/sub th/ values among samples with many times higher resolution compared with a direct R/sub thJC/ measurement.}, language = {en} } @article{MayrockMikhailovSteffensetal., author = {Mayrock, Oliver and Mikhailov, Sergej A. and Steffens, Oliver and R{\"o}ssler, Ulrich}, title = {Observability of the acoustic plasma mode in double-layered quantum dots}, series = {Physica E: Low-dimensional Systems and Nanostructures}, volume = {1}, journal = {Physica E: Low-dimensional Systems and Nanostructures}, number = {1-4}, doi = {10.1016/S1386-9477(97)00048-9}, pages = {232 -- 234}, abstract = {Double-layered quantum dots represent a novel realization of a multi-component plasma system. By modelling the system and applying classical concepts we investigate the oscillator strength of the acoustic plasma mode and its dependence on the system parameters. In view of recent experimental results, we discuss the observability of this collective excitation.}, language = {en} } @misc{KoehlerOstermeierSchaubaecheretal., author = {K{\"o}hler, Ann-Kathrin and Ostermeier, Nadine and Schaub{\"a}cher, Ursula and Wolf, Lars}, title = {Einfluss der W{\"a}rmespeicherf{\"a}higkeit von Massivbauteilen auf den Heizw{\"a}rmebedarf und die Behaglichkeit eines Geb{\"a}udes}, address = {Regensburg}, subject = {W{\"a}rmespeicherung}, language = {de} } @techreport{SchaubeckSteffensRechenauer, author = {Schaubeck, Simon and Steffens, Oliver and Rechenauer, Christian}, title = {Integration eines kostenoptimierten, wirtschaftlich rentablen Blockheizkraftwerks mit mittlerer thermischer Leistung in ein genossenschaftliches Wohnquartier}, language = {de} } @inproceedings{RechenauerNeuleitnerSteffens, author = {Rechenauer, Christian and Neuleitner, Nikolaus and Steffens, Oliver}, title = {Empirische Untersuchung und Optimierung der Performance eines Modellprojekts f{\"u}r ein Effizienzhaus Plus mit solarthermischem Energiekonzept}, series = {Fachforum Effizienzhaus Plus, 14.07.2015}, booktitle = {Fachforum Effizienzhaus Plus, 14.07.2015}, address = {Hamburg}, language = {de} } @book{Steffens, author = {Steffens, Oliver}, title = {Einfluss der Potentialmodulation auf Magnetotransport und Quantenchaos in lateralen Halbleiter-{\"U}bergittern}, publisher = {Tectum-Verl.}, address = {Marburg}, isbn = {978-3-89608-726-3}, pages = {113}, language = {de} } @techreport{Steffens, author = {Steffens, Oliver}, title = {Saisonale W{\"a}rmespeicherung von opaken Bauteilen im Massivbau}, language = {de} } @article{RaithSchmidlingWindisch, author = {Raith, Lea and Schmidling, Anja and Windisch, Bastian}, title = {Bauteiltemperierung}, address = {Regensburg}, language = {de} } @article{SteffensSuhrkeRotteretal., author = {Steffens, Oliver and Suhrke, Michael and Rotter, Peter and R{\"o}ssler, Ulrich}, title = {From Landau levels to universal fluctuations: Level statistics for lateral superlattices}, series = {Physical Review B}, volume = {55}, journal = {Physical Review B}, number = {7}, doi = {10.1103/PhysRevB.55.4486}, pages = {4486 -- 4493}, abstract = {We study the energy-level statistics for electrons in a lateral two-dimensional superlattice in dependence on the strength of the modulation potential at a given perpendicular magnetic field. The interminiband statistics at some selected point in the magnetic Brillouin zone shows a transition from degenerate Landau levels to universal spectral correlations while the corresponding classical dynamics displays a crossover from regular cyclotron orbits to chaotic motion. In terms of the nearest-neighbor spacing distribution, we observe the occurrence of level repulsion for all nonzero modulation amplitudes, which indicates a discontinuous transition to universal fluctuations for the smallest level spacings when the rotational invariance of the system is broken by a finite superlattice potential. In order to test the universality of the transition on larger scales, we propose a random matrix model with one transition parameter for comparison. Confirmed by two different types of potential shapes, we detect an explicit influence of the potential shape on the level spacing distributions, which hence cannot be described by the one-parameter model. Using the spectral rigidity, however, universal long-range fluctuations in the regime of negligible Landau-level mixing are found, in agreement with our random matrix model.}, language = {en} } @article{SteffensWensauerSuhrke, author = {Steffens, Oliver and Wensauer, Andreas and Suhrke, Michael}, title = {Collective excitations in quantum dots: Calculated Raman spectra}, series = {physica status solidi (b)}, volume = {215}, journal = {physica status solidi (b)}, publisher = {Wiley}, doi = {10.1002/(SICI)1521-3951(199909)215:1<365::AID-PSSB365>3.0.CO;2-C}, pages = {365 -- 371}, abstract = {Electronic Raman scattering provides information on excited states, whose collective character as being related to the charge or spin density can be distinguished by using different polarization configurations. We employ time-dependent spin-density functional theory to calculate Raman spectra for circular semiconductor quantum dots with up to 10 electrons for the polarized and depolarized configuration and in dependence on an external magnetic field and the momentum transfer. Our results demonstrate an increase of the collective (or many-particle) character of the excitations with increasing momentum transfer and a mixing of spin- and charge-density modes for excitations from ground states with finite spin density. These results have predictive character, because corresponding experiments on few-electron dots have not yet been performed.}, language = {en} } @article{SuhrkeSteffensRotteretal., author = {Suhrke, Michael and Steffens, Oliver and Rotter, Peter and R{\"o}ssler, Ulrich}, title = {Quantum chaos and magnetotransport in lateral superlattices: The transition from weak to strong modulation potential}, series = {Physica E: Low-dimensional Systems and Nanostructures}, volume = {1}, journal = {Physica E: Low-dimensional Systems and Nanostructures}, number = {1-4}, issn = {1386-9477}, doi = {10.1016/S1386-9477(97)00060-X}, pages = {281 -- 287}, abstract = {Magnetotransport in lateral superlattices covers a variety of apparently different physics dependent on the amplitude of the modulation potential relative to the Fermi energy ranging from the weakly modulated 2DEG to the antidot lattice. Here we investigate the transition between weak modulation and antidots within the quantum-mechanical theory by studying (i) the single-particle spectrum with respect to quantum signatures of classical chaos and (ii) the change of characteristic features in the magnetoresistance starting from the Kubo formula.}, language = {en} } @techreport{SteffensRoesslerSuhrke, author = {Steffens, Oliver and R{\"o}ssler, Ulrich and Suhrke, Michael}, title = {Comment on "Shell Filling and Spin Effects in a Few Electron Quantum Dot"}, series = {Physical Review Letters}, volume = {77}, journal = {Physical Review Letters}, pages = {3613}, abstract = {We briefly report on calculated addition spectra for electrons in a circular quantum dot with perpendicular magnetic field. We compare our current density functional theory calculations with recent experiments by Tarucha et al. [PRL 77, 3613 (1996)]. We find a very good qualitative agreement of the structures and find an additional effect caused by Hund's first rule in magnetic field, which gives rise to new substructures not discussed in the paper by Tarucha.}, language = {en} } @article{Steffens, author = {Steffens, Oliver}, title = {Energetische Modernisierung und Restaurierung historisch wertvoller Stadtquartiere. Regenerative Energieversorgung als Schwerpunkt einer nachhaltigen Modernisierung historisch wertvoller Stadtquartiere (RENARHIS)}, series = {Zukunft bauen. Forschungsinitiative Zukunft Bau 2016}, journal = {Zukunft bauen. Forschungsinitiative Zukunft Bau 2016}, number = {5}, publisher = {Bundesministerium f{\"u}r Umwelt, Naturschutz, Bau und Reaktorsicherheit (BMUB)}, pages = {62 -- 65}, language = {de} } @misc{SteffensSaller, author = {Steffens, Oliver and Saller, Tobias}, title = {Modernisierungskonzepte f{\"u}r das denkmalgesch{\"u}tzte Ensemble am Jahn-Stadion Regensburg Pr{\"u}feninger Straße 47-52}, language = {de} } @techreport{OPUS4-2062, title = {Energienutzungsplan f{\"u}r die Gemeinde Sinzing}, editor = {Neuleitner, Nikolaus and Steffens, Oliver}, organization = {Hochschule f{\"u}r ANgewandte Wissenschaften Regensburg}, language = {de} } @incollection{Gerhards, author = {Gerhards, Helene}, title = {Von Patient*innenzellen und Patient*innenzahlen}, series = {Intersektionalit{\"a}t und Postkolonialit{\"a}t ; kritische feministische Perspektiven auf Politik und Macht}, booktitle = {Intersektionalit{\"a}t und Postkolonialit{\"a}t ; kritische feministische Perspektiven auf Politik und Macht}, editor = {Mauer, Heike and Leinius, Johanna and Gerhards, Helene}, publisher = {Verlag Barbara Budrich}, address = {Opladen; Berlin}, isbn = {9783847424550}, doi = {10.3224/84742455}, pages = {181 -- 203}, language = {de} } @article{HartmannHecknerPlach, author = {Hartmann, Julia and Heckner, Markus and Plach, Ulrike}, title = {Future Skills bei Studierenden - Messung und Einflussfaktoren}, series = {Die Neue Hochschule}, journal = {Die Neue Hochschule}, number = {6}, pages = {24 -- 27}, abstract = {Eine sich stetig ver{\"a}ndernde Arbeitswelt erfordert neue Kompetenzen von unseren Studierenden. In der Lehre gilt es nicht nur, diese Zukunftskompetenzen (sog. Future Skills) zu f{\"o}rdern, sondern diese auch zu messem und sichtbar zu machen.}, language = {de} } @misc{HartmannHecknerPlach, author = {Hartmann, Julia and Heckner, Markus and Plach, Ulrike}, title = {Einfluss studierendenzentrierter Lehrelemente auf die Entwicklung von Zukunftskompetenzen bei Studierenden}, language = {de} } @misc{Hartmann, author = {Hartmann, Julia}, title = {Der Einfluss verschiedener Lehr-Lern-Formate auf das studentische Engagement und die Entwicklung von Future Skills bei Studierenden}, language = {de} } @article{KoenigGuertler, author = {Koenig, Eric and Guertler, Katherine}, title = {One Size Does Not Fit All: Individuality and Perceptions of Improvement and Satisfaction Among TE Students}, series = {English Teaching \& Learning}, volume = {45}, journal = {English Teaching \& Learning}, number = {3}, publisher = {Springer Nature}, doi = {10.1007/s42321-021-00076-4}, pages = {303 -- 324}, abstract = {Academic self-regulation is a key factor for motivation and learning achievement. Yet with the large range of individual factors, this is not a one-size-fits-all proposition. This study of L2 Technical English students at two German universities explored learners' expectations and motivations, in particular regarding self-regulation and self-efficacy via the individual's time investment in self-led study. In an initial survey, learners (N=1646) reported on their English skill levels and anticipated learning habits. Complementarily, the retrospective survey investigated learners' (N=796) actual behavior during the course, their perceptions of language skill improvement, and their satisfaction. The initial survey indicates a clear understanding that time investment in self-regulated study will lead to greater improvement, an outcome confirmed in the retrospective survey. Additionally, students who invested more time in their coursework were more satisfied with their achievement, although most learners acknowledge they should have studied more. The results verify that learners recognize the nexus between self-regulation and language skill improvement, yet university students are not satisfied with their capacity to self-regulate their language learning strategies. While differences in students' skill levels and academic self-efficacy result in divergent degrees of progress, students of all types report benefits to their language skills when motivated to self-regulated study.}, language = {en} } @article{YeapMeisterOhetal., author = {Yeap, Kim Ho and Meister, Tobias and Oh, Zi Xin and Nisar, Humaira}, title = {Circuit Modelling Methodology for Dual-band Planar Antennas}, series = {APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY JOURNAL}, volume = {36}, journal = {APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY JOURNAL}, number = {8}, publisher = {APPLIED COMPUTATIONAL ELECTROMAGNETICS SOC}, doi = {10.47037/2021.ACES.J.360822}, pages = {1112 -- 1115}, abstract = {This paper presents a simple and systematic approach to determine the equivalent frequency-independent circuit model for a dual-band planar antenna. The Foster Canonical network synthesis technique with two RLC tanks has been employed to generate the two resonant bands of the antenna. The transfer function model is subsequently refined using a data fitting algorithm (viz the Nelder-Mead simplex algorithm). Parametric adjustments are performed at the final stage in order to further improve the accuracy of the final parameters.}, language = {en} } @article{LiStockSchlamminger, author = {Li, Shisong and Stock, Michael and Schlamminger, Stephan}, title = {A new magnet design for future Kibble balances}, series = {Metrologia}, volume = {55}, journal = {Metrologia}, number = {3}, publisher = {IOP PUBLISHING}, doi = {10.1088/1681-7575/aab2ea}, pages = {319 -- 325}, abstract = {We propose a new permanent magnet system for Kibble balance experiments, which combines advantages of the magnet designs invented by the National Physical Laboratory (NPL) and by the Bureau International des Poids et Mesures (BIPM). The goal of the proposed magnet system is to minimize the coil-current effect and to optimize the shielding at the same time. In the proposed design, a permanent magnet system with two gaps, each housing a coil, is employed to minimize the coil current effect, by reducing the linear coil-current dependence reported for the single air gap design by at least one order of magnitude. Both air gaps of the magnet are completely surrounded by high-permeability material, and hence the coils are shielded from outside magnetic fields and no magnetic field leaks outside of the magnet system. An example of the new magnet system is given and the analysis shows that the magnetic field in the air gap can be optimized to meet the requirement to be used in Kibble balances.}, language = {en} } @article{SchreinerLangerPrommesbergeretal., author = {Schreiner, Rupert and Langer, Christoph and Prommesberger, Christian and Dams, Florian}, title = {Compact and Energy-Efficient Field Emission Cathodes for Sensor Applications}, series = {Advanced Materials Research}, volume = {1024}, journal = {Advanced Materials Research}, publisher = {Scientific.net}, doi = {10.4028/www.scientific.net/amr.1024.372}, pages = {372 -- 375}, abstract = {We report on miniaturized silicon field emitter arrays for the application in compact and energy-saving vacuum-microelectronic devices, e.g. sensors or x-ray tubes. Since standard silicon semiconductor technology has been used for the fabrication, they may be easily integrated with other silicon based circuits and devices on the same chip. The silicon tip geometry and the operating conditions were optimized in order to obtain highly uniform and stable electron field emission from large area cathode arrays. A series of uniform hexagonal tip arrays containing each 547 tips were fabricated and characterized. The electron emission properties of both individual tips as well as of complete emitter arrays were investigated. A saturation level in the voltage-current characteristics was found, which can be explained by the limitation of the supply of electrons due to the p-type silicon wafer material. When operating the arrays in the current saturation regime at an emission current of ~ 1 nA per tip, a highly stable and low noise emission can be observed.}, language = {en} } @article{CheeKammlerGrahametal., author = {Chee, See Wee and Kammler, Martin and Graham, Jeremy and Gignac, Lynne and Reuter, Mark C. and Hull, Robert and Ross, Frances M.}, title = {Directed Self-Assembly of Ge Quantum Dots Using Focused Si2+ Ion Beam Patterning}, series = {scientific reports}, volume = {8}, journal = {scientific reports}, publisher = {Nature}, doi = {10.1038/s41598-018-27512-z}, pages = {1 -- 10}, abstract = {We show that templating a Si surface with a focused beam of Si2+ or Si+ ions can create suitable nucleation sites for the subsequent growth of self-assembled Ge quantum dots by chemical vapor deposition. To determine the mechanism of patterning we use atomic force microscopy to show that, similar to Ga+ patterning, the formation of a surface pit is required to enable control over Ge quantum dot locations. We find that relatively high implantation doses are required to achieve patterning, and these doses lead to amorphization of the substrate. We assess the degree to which the substrate crystallinity can be recovered by subsequent processing. Using in situ transmission electron microscopy heating experiments we find that recrystallization is possible at the growth temperature of the Ge quantum dots, but defects remain that follow the pattern of the initial implantation. We discuss the formation mechanism of the defects and the benefits of using Si ions for patterning both defects and quantum dots on Si substrates.}, language = {en} } @article{SchnitzerRichterWalteretal., author = {Schnitzer, Susanne and Richter, Stefanie and Walter, Andreas and Balke, Klaus and Kuhlmey, Adelheid}, title = {Die Bewertung der ambulanten Gesundheitsversorgung aus Versichertensicht}, series = {Gesundheits- und Sozialpolitik}, volume = {62}, journal = {Gesundheits- und Sozialpolitik}, number = {5}, publisher = {Nomos}, pages = {11 -- 20}, abstract = {In den letzten Jahren haben verschiedene Institutionen bev{\"o}lkerungsrepr{\"a}sentative Befragungen zur Bewertung von Einzelaspekten der Gesundheitsversorgung durchgef{\"u}hrt (Bertelsmann Gesundheitsmonitor, Commonwealth Fund, Gesundheitssurvey des Robert Koch-Instituts, BKK-Befragung, WIdO-monitor). Hierzu z{\"a}hlt auch die Kassen{\"a}rztliche Bundesvereinigung (KBV), die im Jahr 2006 die Forschungsgruppe Wahlen Telefonfeld (FGW) in Mannheim beauftragte, repr{\"a}sentativ gesetzlich und privat Versicherte zur Zufriedenheit mit der ambulanten Versorgung sowie zum Bedarf an neuen Dienstleistungsangeboten zu befragen (KBV 2006; Rieser 2006). Eine zweite Versichertenbefragung der KBV erfolgte im Zeitraum Mai und Juni 2008, wiederum von der FGW durchgef{\"u}hrt. Die Ergebnisse dieser repr{\"a}sentativen Erhebung werden im Rahmen von zwei Artikeln in Gesundheits- und Sozialpolitik vorgestellt. Im Zentrum des hier vorliegenden ersten Beitrags stehen die Inanspruchnahme der ambulanten haus- und fach{\"a}rztlichen Versorgung, die Erfahrungen mit Terminvergabe und Wartezeiten sowie die Bewertungen der Versorgung durch die Versicherten. Dar{\"u}ber hinaus wird die Bedeutung von Individuellen Gesundheitsleistungen (IgeL) in der ambulanten Versorgung gesetzlich Versicherter diskutiert. Der zweite Artikel wird sich schwerpunktm{\"a}ßig mit den Qualit{\"a}tskriterien f{\"u}r die Wahl eines Arztes, mit den Erfahrungen von Ver{\"a}nderungen in der Medikamentenverordnung sowie mit der Akzeptanz neuer Versorgungsformen und Wahltarife befassen.}, language = {de} } @article{SchnitzerRichterWalteretal., author = {Schnitzer, Susanne and Richter, Stefanie and Walter, Andreas and Balke, Klaus and Kuhlmey, Adelheid}, title = {Die Bewertung der ambulanten Gesundheitsversorgung aus Versichertensicht}, series = {Gesundheits- und Sozialpolitik}, volume = {62}, journal = {Gesundheits- und Sozialpolitik}, number = {6}, publisher = {Nomos}, pages = {19 -- 27}, abstract = {In der Ausgabe 5/2008 von „Gesundheits- und Sozialpolitik" wurden erste Ergebnisse der zweiten Versichertenbefragung der Kassen{\"a}rztlichen Bundesvereinigung (KBV) vorgestellt. Der Fokus der Darstellung lag im ersten Teil auf dem Inanspruchnahmeverhalten und der Zufriedenheit der Versicherten mit der {\"a}rztlichen Versorgung, wobei der Aspekt der Wartezeiten auf einen Termin und in der Arztpraxis ausf{\"u}hrlich behandelt wurde. Insgesamt ist eine hohe Inanspruchnahme der haus- und fach{\"a}rztlichen ambulanten Versorgung zu konstatieren sowie eine {\"u}berwiegende Zufriedenheit mit der {\"a}rztlichen Betreuung. Die Ergebnisse zu den Wartezeiten auf einen Arzttermin spiegeln im Vergleich zu {\"o}ffentlich gef{\"u}hrten Debatten ein differenziertes Bild wider. Im zweiten Teil werden folgende Fragen vertiefend diskutiert: Welche Kriterien sind neben der fachlichen Kompetenz (f{\"u}r die Versicherten) f{\"u}r die Wahl der Arztpraxis relevant? Welche Bedeutung haben G{\"u}tesiegel als Qualit{\"a}tsmarker f{\"u}r die Versicherten? Welche Erfahrungen haben die Versicherten mit {\"A}nderungen in der Medikamentenverordnung gemacht? Nehmen die Versicherten an Hausarztmodellen teil und wie bewerten sie die Versorgungsqualit{\"a}t? Welche Akzeptanz haben unterschiedliche Wahltarife bei den gesetzlich Versicherten?}, language = {de} } @article{BalkeSchnitzerWalteretal., author = {Balke, Klaus and Schnitzer, Susanne and Walter, Andreas and Richter, Stefanie and Kuhlmey, Adelheid}, title = {Wartezeit ist ein wichtiges Kriterium bei der Wahl der Arztpraxis}, series = {Deutsches {\"A}rzteblatt}, volume = {105}, journal = {Deutsches {\"A}rzteblatt}, number = {34-35}, publisher = {Deutscher {\"A}rzteverlag}, pages = {A1766 -- A1768}, abstract = {{\"A}ltere Patienten und Frauen warten l{\"a}nger auf einen Arzttermin als junge Versicherte und M{\"a}nner, gesetzlich Versicherte l{\"a}nger als Privatpatienten. Die meisten Patienten sind aber keineswegs unzufrieden. 90 Prozent bekommen entweder am selben Tag einen Termin oder halten die Wartezeit f{\"u}r angemessen.}, language = {de} } @inproceedings{HausladenBomkeBuchneretal., author = {Hausladen, Matthias and Bomke, Vitali and Buchner, Philipp and Bachmann, Michael and Knapek, Alexandr and Schreiner, Rupert}, title = {Influence of Geometrical Arrangements of Si Tip Arrays Fabricated by Laser Micromachining on their Emission Behaviour}, series = {2021 34th International Vacuum Nanoelectronics Conference (IVNC): 7/5/2021 - 7/9/2021, Lyon, France}, booktitle = {2021 34th International Vacuum Nanoelectronics Conference (IVNC): 7/5/2021 - 7/9/2021, Lyon, France}, publisher = {IEEE}, address = {Piscataway, N.J.}, isbn = {978-1-6654-2589-6}, issn = {2380-6311}, doi = {10.1109/IVNC52431.2021.9600717}, abstract = {ensely packed emitters on a field emission array lead typically to mutual shielding. Taking biology as a role model for geometric arrangements could be a way to reduce this effect. For comparison, two electron sources, one with a spiral and a second with conventional rectangular (orthogonal) arranged emitters, were fabricated and investigated. Emission currents of 6 µA in the spiral ordered array and 120 µA in the rectangular array were reached with an extraction voltage of 400 V. From a mid-term measurement over 1 h a current stability of ±8.8 \% (spiral) respectively ±5.7 \% (rectangular) with a mean degradation of -3.0 µA/h (spiral) and -0.12 µA/h (rectangular) could be observed.}, language = {en} } @inproceedings{BuchnerBomkeHausladenetal., author = {Buchner, Philipp and Bomke, Vitali and Hausladen, Matthias and Edler, Simon and Bachmann, Michael and Schreiner, Rupert}, title = {Investigation on the Emission Behaviour of p-doped Silicon Field Emission Arrays with Individually Controllable Single Tips}, series = {2021 34th International Vacuum Nanoelectronics Conference (IVNC): 7/5/2021 - 7/9/2021, Lyon, France}, booktitle = {2021 34th International Vacuum Nanoelectronics Conference (IVNC): 7/5/2021 - 7/9/2021, Lyon, France}, publisher = {IEEE}, isbn = {978-1-6654-2589-6}, doi = {10.1109/IVNC52431.2021.9600756}, pages = {1 -- 2}, abstract = {Four individually controllable emission tips consisting of <111> p-Type silicon, were structured on a glass substrate by laser ablation. A matching extraction grid was manufactured in the same manner and aligned with the emitters. The resulting samples were characterized in ultra-high vacuum. As expected, the individual currents show a strong saturation and in the saturation region a considerably lower current fluctuation than n-type silicon due to charge carrier depletion. The individual tips behave completely independent behaviour from each other and the overall emission can be deduced from the sum of the currents through the individual tips.}, language = {en} } @inproceedings{HechtBauereiβSellmairetal., author = {Hecht, Fabian and Bauereiβ, Florian and Sellmair, Josef and Buchner, Philipp and Hausladen, Matthias and Schreiner, Rupert}, title = {Electron Beam Induced Growth of Carbon Nanotips on Tungsten and Silicon Fieldemitters}, series = {2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA}, booktitle = {2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA}, publisher = {IEEE}, isbn = {979-8-3503-0143-4}, doi = {10.1109/IVNC57695.2023.10188960}, pages = {160 -- 162}, abstract = {In our experiments we grew electron emitting carbon nanostructures on tungsten tips. Subsequently, we transferred the growth process to pre-structured phosphorus-doped n-type silicon and obtained emitting carbon nanostructures directly grown on silicon. After growth of the nanostructures, the silicon field emitters showed increased emission currents of 76 nA at 1.1 kV (compared to 6 nA under the same conditions before growth).}, language = {en} } @inproceedings{HoellerBloedt, author = {H{\"o}ller, Christoph and Bl{\"o}dt, Adrian}, title = {Messung und Bewertung von elastischen Bodenbel{\"a}gen auf tief abgestimmten schwimmenden Estrichen in Fitnessstudios}, series = {Tagungsband DAGA 2021: 47. Jahrestagung f{\"u}r Akustik, 15.-18. August 2021, Wien und Online}, booktitle = {Tagungsband DAGA 2021: 47. Jahrestagung f{\"u}r Akustik, 15.-18. August 2021, Wien und Online}, publisher = {Deutsche Gesellschaft f{\"u}r Akustik e.V.}, address = {Berlin}, language = {de} } @inproceedings{AllahamBuchnerSchreineretal., author = {Allaham, Mohammad M. and Buchner, Philipp and Schreiner, Rupert and Kn{\´a}pek, Alexandr}, title = {Testing the performance of Murphy-Good plots when applied to current-voltage characteristics of Si field electron emission tips}, series = {2021 34th International Vacuum Nanoelectronics Conference (IVNC): 5-9 July 2021, Lyon, France}, booktitle = {2021 34th International Vacuum Nanoelectronics Conference (IVNC): 5-9 July 2021, Lyon, France}, publisher = {IEEE}, doi = {10.1109/IVNC52431.2021.9600690}, pages = {1 -- 2}, abstract = {Murphy-Good plots are the most recent type of the analysis methods in the field electron emission theory, this type of plots has several useful characteristics such as: having the very-nearly straight line to represent the current-voltage characteristics and the absence of the correction factors in the mathematical procedure of the analysis process. In this study, n-type <111> and <100> Si chips containing four individual emitters are used as base emitters and mounted in a diode configuration field emission setup where the experiments are operated in an ultra-high vacuum ( 10-7 Pa). Each chip has four individual controllable emitters with 5 µm distance between the Si tips and the same material grid. Laser micromachining and subsequent wet chemical etching technique is used to structure and polish the tips. Murphy-Good plots are used to study the behavior of the Si individual tips and compare the results with the array current by extracting the field emission characterization parameters of the emitters.}, language = {en} } @inproceedings{BlahnikovaMuellerWaasetal., author = {Blahn{\´i}kov{\´a}, Barbora and M{\"u}ller, D. and Waas, M. and Lechner, Alfred}, title = {Multilyzer - microfluidic online measuring system for the analysis of environmentally relevant substances}, series = {AMA Conferences 2017 : Proceedings : SENSOR 2017 / N{\"u}rnberg 2017-05-30 - 2017-06-01}, booktitle = {AMA Conferences 2017 : Proceedings : SENSOR 2017 / N{\"u}rnberg 2017-05-30 - 2017-06-01}, publisher = {AMA Service GmbH}, address = {Wunstorf}, isbn = {978-3-9816876-4-4}, doi = {10.5162/sensor2017/P5.2}, pages = {696 -- 699}, language = {en} }