TY - JOUR A1 - Pangerl, Jonas A1 - Sukul, Pritam A1 - Rück, Thomas A1 - Fuchs, Patricia A1 - Weigl, Stefan A1 - Miekisch, Wolfram A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - An inexpensive UV-LED photoacoustic based real-time sensor-system detecting exhaled trace-acetone JF - Photoacoustics N2 - n this research we present a low-cost system for breath acetone analysis based on UV-LED photoacoustic spectroscopy. We considered the end-tidal phase of exhalation, which represents the systemic concentrations of volatile organic compounds (VOCs) – providing clinically relevant information about the human health. This is achieved via the development of a CO2-triggered breath sampling system, which collected alveolar breath over several minutes in sterile and inert containers. A real-time mass spectrometer is coupled to serve as a reference device for calibration measurements and subsequent breath analysis. The new sensor system provided a 3σ detection limit of 8.3 ppbV and an NNEA of 1.4E-9 Wcm 1Hz 0.5. In terms of the performed breath analysis measurements, 12 out of 13 fell within the error margin of the photoacoustic measurement system, demonstrating the reliability of the measurements in the field. KW - Photoacoustic spectroscopy KW - Real-time mass-spectrometry KW - Breath analysis KW - Acetone KW - UV-LED Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-71279 SN - 2213-5979 N1 - Corresponding author der OTH Regensburg: Jonas Pangerl VL - 38 PB - Elsevier ER - TY - JOUR A1 - Hausler, Peter A1 - Holzner, Lukas A1 - Ehrnsperger, Matthias A1 - Bierl, Rudolf T1 - Evaluation of the creep strength of samples produced by fused deposition modeling JF - Open Engineering N2 - Data sheets for 3D printing materials typically include softening temperature, impact strength, tensile strength, and stiffness. However, creep strength, an important parameter for components used over an extended period, is usually not included. Nevertheless, this parameter is of significant importance for components that are used over an extended period of time.This study compares the long-term creep behavior of a selection of materials that are commonly used in fused deposition modeling 3D printing. The materials under investigation are acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, polylactic acid, and polycarbonate. In addition, the influence of fiber reinforcements on these materials is also examined. A simple, reproducible test procedure is proposed for users to determine and compare creep resistance of materials. This enables developers to select materials suitable for their own requirements on creep resistance and allows 3D-printing users to compare different materials. Results suggest that fiber reinforcement generally improves creep stability in 3D-printing materials, with GreenTEC Pro Carbon and add:north PC Blend HT LCF showing the most promise in this study. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-79760 N1 - Corresponding author der OTH Regensburg: Peter Hausler VL - 14 IS - 1 PB - de Gruyter ER - TY - JOUR A1 - Schels, Andreas A1 - Edler, Simon A1 - Herdl, Florian A1 - Hansch, Walter A1 - Bachmann, Michael A1 - Ritter, Daniela A1 - Dudeck, Markus A1 - Duesberg, Felix A1 - Meyer, Manuel A1 - Pahlke, Andreas A1 - Hausladen, Matthias A1 - Buchner, Philipp A1 - Schreiner, Rupert T1 - In situ quantitative field emission imaging using a low-cost CMOS imaging sensor JF - Journal of Vacuum Science & Technology B N2 - Spatially resolved field emission measurements represent an important factor in further development of existing field emitter concepts. In this work, we present a novel approach that allows quantitative analysis of individual emission spots from integral current-voltage measurements using a low-cost and commercially available CMOS camera. By combining different exposure times to extrapolate oversaturated and underexposed pixels, a near congruence of integral current and image brightness is shown. The extrapolation also allows parallel investigation of all individual tips participating in the total current with currents ranging from a few nanoampere to one microampere per tip. The sensitivity, which is determined by the integral brightness-to-current ratio, remains unchanged within the measurement accuracy even after ten full measurement cycles. Using a point detection algorithm, the proportional current load of each individual tip of the field emitter array is analyzed and compared at different times during the initial measurement cycle. Together with the extracted I-V curves of single emission spots from the integral measurement, the results indicate the effect of premature burnout of particularly sharp tips during conditioning of the emitter. KW - ARRAYS KW - ELECTRON-EMISSION KW - EMITTERS KW - FakANK Y1 - 2022 U6 - https://doi.org/10.1116/6.0001551 VL - 40 IS - 1 PB - AIP Publishing ER - TY - JOUR A1 - Edler, Simon A1 - Schels, Andreas A1 - Herdl, Florian A1 - Hansch, Walter A1 - Bachmann, Michael A1 - Dudeck, Markus A1 - Duesberg, Felix A1 - Pahlke, Andreas A1 - Hausladen, Matthias A1 - Buchner Philipp, A1 - Schreiner, Rupert T1 - Origin of the current saturation level of p-doped silicon field emitters JF - Journal of Vacuum Science & Technology B N2 - Using p-type semiconductors for field emitters is one simple way to realize an integrated current limiter to improve the lifetime of the cathode. In this work, the origin of the current saturation of p-type silicon emitters is investigated in detail. Single emitters are electrically characterized and compared to simulation results. With a simulation model considering a high surface generation rate and elevated tip temperature, a good agreement to the measured data is found. This observation is supported further by alteration of the surface experimentally. Electrical measurements after different treatments in hydrofluoric acid as well as heated and subsequent operation at room temperature are well explained by the influence of surface generation. Furthermore, it is shown that the field penetration leads to a small voltage drop and a strong geometry-dependent reduction of the field enhancement factor. KW - EMISSION KW - GROWTH KW - NATIVE-OXIDE Y1 - 2022 U6 - https://doi.org/10.1116/6.0001554 VL - 40 IS - 1 PB - AIP Publishing ER - TY - JOUR A1 - Milewski, Nadja A1 - Haug, Sonja T1 - At risk of reproductive disadvantage? Exploring fertility awareness among migrant women in Germany JF - Reproductive Biomedicine & Society Online N2 - This study examined awareness about fertility among immigrant women and non-migrants in Germany. The social relevance of infertility and fertility treatment is increasing in Western countries due to continually low overall birth rates, a high rate of childlessness, and a gap between the desired and actual numbers of children. While there is growing interest in infertility and reproductive medicine in general, previous studies have rarely included immigrant or ethnic minorities in Europe. This study investigated whether knowledge on the age-related fertility decline (ARFD) varies between migrant groups and the majority group, and the role of education. Working hypotheses were drawn from theoretical considerations on frameworks of migrant assimilation. The analysis was based on data collected in a social science pilot study on reproductive medicine, representative of the general population (‘NeWiRe’ 2014–2015). The sample included 962 women aged 18–50 years living in Germany. Approximately 81% of the sample were immigrants who originated from Turkey, Poland, the Balkan countries or countries of the (post-Soviet) Commonwealth of Independent States. While rather poor overall, knowledge on ARFD was found to be significantly lower in the migrant groups compared with the majority group. This minority-group disadvantage cannot be explained by sociodemographic or cultural variables. Future research should include minority groups in empirical studies on awareness about fertility in order to better understand the causes of this disadvantage, and the potential reproductive needs of migrants. KW - Age-related fertility decline KW - Fertility knowledge KW - Migrant assimilation KW - Minority groups KW - Non-patient sample Y1 - 2022 U6 - https://doi.org/10.1016/j.rbms.2021.11.007 VL - 14 SP - 226 EP - 238 PB - Elsevier ER - TY - CHAP A1 - Höller, Christoph T1 - Review and Comparison of ASTM and ISO Standards on Sound Transmission in Buildings T2 - Impact of noise control engineering : 47th International Congress and Exposition on Noise Control Engineering (INTERNOISE 2018) : Chicago, Illinois, USA, 26-29 August 2018 Y1 - 2018 UR - https://internoise2018.org/ PB - Curran Associates, Inc. CY - Red Hook, NY ER - TY - GEN A1 - Hartmann, Julia T1 - Developing future competencies by combining case-based learning, knowledge nuggets and gamification KW - Future Skills KW - Knowledge Nuggets KW - Gamification KW - Case-based learning KW - Innovation in der Lehre Y1 - 2023 ER - TY - JOUR A1 - Reinker, Lukas A1 - Bläsing, Dominic A1 - Bierl, Rudolf A1 - Ulbricht, Sabina A1 - Dendorfer, Sebastian T1 - Correlation of Acceleration Curves in Gravitational Direction for Different Body Segments during High-Impact Jumping Exercises JF - sensors N2 - Osteoporosis is a common disease of old age. However, in many cases, it can be very well prevented and counteracted with physical activity, especially high-impact exercises. Wearables have the potential to provide data that can help with continuous monitoring of patients during therapy phases or preventive exercise programs in everyday life. This study aimed to determine the accuracy and reliability of measured acceleration data at different body positions compared to accelerations at the pelvis during different jumping exercises. Accelerations at the hips have been investigated in previous studies with regard to osteoporosis prevention. Data were collected using an IMU-based motion capture system (Xsens) consisting of 17 sensors. Forty-nine subjects were included in this study. The analysis shows the correlation between impacts and the corresponding drop height, which are dependent on the respective exercise. Very high correlations (0.83–0.94) were found between accelerations at the pelvis and the other measured segments at the upper body. The foot sensors provided very weak correlations (0.20–0.27). Accelerations measured at the pelvis during jumping exercises can be tracked very well on the upper body and upper extremities, including locations where smart devices are typically worn, which gives possibilities for remote and continuous monitoring of programs. KW - osteoporosis KW - inertial measurement units KW - wearable motion-tracking sensors KW - high-impact exercisess Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-58217 N1 - Corresponding author: Lukas Reinker N1 - This work was supported by the Bavarian Academic Forum [BayWISS-Verbundkolleg Gesundheit] and the DHZK fond for behavioral cardiovascular diseases [Behaviorale kardiovaskuläre Erkrankungen; grand number: 81Z0400105]. VL - 23 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Steffens, Oliver A1 - Suhrke, Michael T1 - Novel spin features in Raman spectra of few-electron quantum dots JF - Physical Review Letters N2 - We employ a self-consistent, dynamic spin-density functional concept beyond the dipole approximation in order to calculate the collective modes of few-electron quantum dots with partial spin polarization. Because of Hund's rule in a magnetic field the mode energies exhibit characteristic discontinuities in their magnetic-field dependence, which is a manifestation of ground-state transitions between different spin configurations. A finite ground-state spin density couples collective charge- and spin-density excitations. We predict their observability in state-of-the-art Raman experiments. Y1 - 1999 U6 - https://doi.org/10.1103/PhysRevLett.82.3891 VL - 82 IS - 19 SP - 3891 EP - 3894 PB - American Physical Society ER - TY - CHAP A1 - Tschurtschenthaler, Karl A1 - Krenkel, Lars A1 - Schreiner, Rupert T1 - Mechano-optical micro pillar sensor for biofluidmechanic wall shear stress measurements T2 - 25th Congress of the European Society of Biomechanics (ESB), July 7-10, 2019, Vienna, Austria Y1 - 2019 UR - https://esbiomech.org/conference/archive/2019vienna/Contribution_608.pdf ER - TY - CHAP A1 - Steffens, Oliver A1 - Suhrke, Michael A1 - Rössler, Ulrich ED - Kramer, Bernhard T1 - Ground state and collective excitations of quantum dots: Correlation effects and Hund’s rule in magnetic field T2 - Advances in Solid State Physics N2 - We review ground-state properties and collective excitations of semiconductor quantum dots in a magnetic field obtained from current-spin density-functional theory. Due to exchange-correlation, a generalized Hund’s rule in magnetic field can be established which leads to spin alignment in partially occupied energy shells at the Fermi energy. This results, in distinct spin structures in single-electron addition spectra. Current-dependent exchange-correlation modifies the magnetic-field dependence of the ground state configuration and leads to deviations from plain spin-density calculations. Moreover it gives rise to spontaneous current textures at zero magnetic field. Collective excitation spectra, explicitly calculated for inelastic light scattering, exhibit novel features in their magnetic field dependence due to a finite ground-state spin density. KW - Spin Density KW - Fermi Energy KW - Collective Excitation KW - Addition Spectrum KW - Inelastic Light Scattering Y1 - 1999 SN - 978-3-540-44553-1 U6 - https://doi.org/10.1007/BFb0107469 VL - 39 SP - 111 EP - 120 PB - Friedr. Vieweg & Sohn CY - Braunschweig ER - TY - GEN A1 - Steffens, Oliver A1 - Saller, Tobias T1 - Restaurierungskonzepte für St. Oswald in Regensburg BT - Studienarbeiten Gebäudemodernisierung Sommer 2015 Y1 - 2015 ER - TY - INPR A1 - Menzel, Andreas A1 - Yeh, Wang-Chi Vincent A1 - Kammler, Martin A1 - Hupalo, Myron A1 - Conrad, E. H. A1 - Tringides, Michael C. T1 - Measurements of the kinetic barriers controlling the formation of the uniform height islands in Pb/Si(111) N2 - As demonstrated with SPA-LEED and STM uniform height islands of preferred thickness form during the growth of Pb on Si(111). The islands form at temperatures T<250K and for fluxes F 1/60ML/sec which requires fast kinetics and balance between several atomic processes: diffusion towards the islands , diffusion to higher layers and preference for the atoms to remain on top of the preferred height islands. We have carried out SPA-LEED experiments to measure the barriers of the processes: we prepare an initial predominantly 5-step island height distribution and we deposit an additional 0.5ML Pb at different growth temperatures Tg to determine the transition to the next preferred height of 7-step islands (i.e. 2-step islands on top of the 5-step islands) with Spot Profile Analysis(SPA-LEED). We observe that 7-step island formation is possible above a minimum temperature Tg*=175K which indicates that the transfer of atoms from the surrounding region to the top of the islands is the main controlling process. Y1 - 2002 UR - https://www.researchgate.net/publication/259264144_Measurements_of_the_kinetic_barriers_controlling_the_formation_of_the_uniform_height_islands_in_PbSi111 ER - TY - INPR A1 - Cavalleri, Andrea A1 - Siders, Craig A1 - Toth, Csaba A1 - Squier, Jeff A. A1 - Barty, C. P. J. A1 - Wilson, K. R. A1 - Sokolowski-Tinten, Klaus A1 - von der Linde, Dietrich A1 - Kammler, Martin A1 - Horn- von Hoegen, Michael T1 - Measurement of harmonic and anharmonic semi-conductor-lattice dynamics with ultrafast x-ray diffraction N2 - Many fundamental processes in solids, such as heat transport and phase transitions involve atomic movement on ultrafast time-scales, but cannot be directly measured with visible light. Using ultrafast x-ray diffraction, atomic motion can be measured on its natural time-scale. Photo-excitation of bulk and layered semiconductors was achieved with 800-nm wavelength femtosecond laser pulses. Optical excitation triggers a chain of relaxation processes, causing rapid lattice heating, generation and propagation of stress/strain waves into the bulk and eventual anharmonic decay of coherent acoustic phonons into the thermal bath of the solid. While the first steps of carrier relaxation, excitation and decay of Raman-active optical phonons have been in the past characterized optically at surfaces, the bulk acoustic dynamics at longer times has not. We measure length scales of lattice excitation, thereby detecting ultrafast heat diffusion via fast electrons, coherent acoustic pulse propagation into the bulk or across buried interfaces and anharmonic damping of non-equilibrium acoustic phonons. The measurement is performed with sensitivity on lattice spacing of 10 femtometers (i.e., 3 nuclear diameters). Y1 - 2000 UR - https://www.researchgate.net/publication/252175863_Measurement_of_harmonic_and_anharmonic_semi-conductor-lattice_dynamics_with_ultrafast_x-ray_diffraction ER - TY - JOUR A1 - Bieker, Johannes A1 - Roustaie, Farough A1 - Schlaak, Helmut F. A1 - Langer, Christoph A1 - Schreiner, Rupert A1 - Lotz, Marcel A1 - Wilfert, Stefan T1 - Field emission characterization of in situ deposited gold nanocones with variable cone densities JF - Journal of Vacuum Science and Technology B N2 - For the fabrication of field emitter cathodes with metallic nanocones, an in situ fabrication technique based on electrodeposition in an ion track etched polymer template was used. Three samples with nanocones made of gold and different cone densities were deposited on a circular electrode with a diameter of 2.5 mm, using templates with pore density of 6 × 104, 4 × 105, and 1 × 106 cones/cm2. The cones had a height of 24 μm, a base diameter between 3 and 3.75 μm, and a tip diameter below 500 nm. Integral field emission measurements revealed onset fields of down to 3.1 V/μm and average field enhancement factors of up to 1240. For one sample, the maximum emission current from the cathode reached 142.2 μA at an applied voltage of 338 V between cathode and extraction grid, which had a distance of 50 μm. To investigate the stability of the field emission current, cumulative long-term measurements were performed for over 50 h. A stable emission current of (31.0 ± 1.3) μA at an average applied voltage of 290 V (E = 5.8 V/μm) was observed. For currents above 100 μA, a decrease of the current and therefore a degradation of the emitter structures occurred. Y1 - 2018 U6 - https://doi.org/10.1116/1.5009504 VL - 36 IS - 2 PB - AIP Publishing ER - TY - CHAP A1 - Dams, Florian A1 - Schreiner, Rupert T1 - A high thermal resistance MEMS-based Pirani vacuum sensor chip T2 - Smart sensors, actuators and MEMS VI : 24 - 26 April 2013, Grenoble, France / [part of SPIE microtechnologies] N2 - The performance of thermal conductivity vacuum gauges can be improved by a well-designed geometry. The lower measurement range limit is determined by the size of the active sensing area and the thermal conduction heat losses through the supporting structures. The upper measurement range is limited by the distance between the heated element and the cold reference plane. Silicon based MEMS-technology gives the possibility to fabricate both sensing structures with suitable areas out of low thermal conductive materials and narrow gaps in order to extend the measurement range in both directions. In this work we present a MEMS-process to fabricate high thermal resistance sensor structures. The rectangular sensitive areas are anchored by four beams and are structured out of low thermal conductive PECVD-siliconnitride films with 1 µm in thickness. The metallic heating structure is completely embedded in the SiN-layer. Both sensitive area and its support beams were released from the silicon bulk material by anisotropic underetching. In this way a free-supporting structure with a gap of 150 μm to the silicon substrate was formed. The influence of the filament geometry and temperature was systematically investigated to determine the properties of the chips as thermal conductivity vacuum gauges. The temperature of the sensitive area was held constant by a self-balancing bridge circuit and the heating power was measured by a Δ-Σ-ADC. The average solid state thermal conductivity is in the order of 106WK1. The measuring range of the most sensitive structures covers 8 orders of magnitude from 105 mbar to 1000mbar. Y1 - 2013 U6 - https://doi.org/10.1117/12.2017345 PB - SPIE CY - Bellingham, Wash. ER - TY - JOUR A1 - Koenig, Eric A1 - Guertler, Katherine T1 - One Size Does Not Fit All: Individuality and Perceptions of Improvement and Satisfaction Among TE Students JF - English Teaching & Learning N2 - 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. KW - English KW - Technical English KW - Self-efficacy KW - Self-regulation KW - Motivation Y1 - 2021 U6 - https://doi.org/10.1007/s42321-021-00076-4 SN - 1023-7267 VL - 45 IS - 3 SP - 303 EP - 324 PB - Springer Science and Business Media ER - TY - JOUR A1 - Stierstorfer, Johannes A1 - Wellnitz, Felix A1 - Steffens, Oliver T1 - Conservation of historic building fabric through integrated building research and digital simulation JF - Bauphysik N2 - The abbey of Weltenburg monastery, a late baroque icon, designed by the Asam brothers and today's world heritage, has been subject to a constant need for repair and restoration due to its geological, climatological, and exposed location on the banks of the river Danube. To solve the hygric problems within the church, an exceptional restoration concept has been executed in the last decade. This research project analyses and verifies the building-physical and indoor climatic effects of the restoration measures with focus on the improvement of the central space climate. With this case study the question is raised whether appropriate measures exist that allow a contemporary and sustainable usage of historic buildings with respect to the preservation of the historic building fabric. Y1 - 2017 U6 - https://doi.org/10.1002/bapi.201710016 VL - 39 IS - 2 SP - 135 EP - 143 PB - ERNST & SOHN ER - TY - GEN A1 - Düsberg, Felix A1 - Bachmann, Michael A1 - Edler, Simon A1 - Pahlke, Andreas A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Schreiner, Rupert A1 - Bunert, Erik A1 - Wendt, Cornelius A1 - Zimmermann, Stefan T1 - Novel Non-Radiative Electron Source T2 - 43rd International Symposium of Capillary Chromatography & 16h GC x GC Symposium 2019 N2 - Recently a non-radioactive electron capture detector based on a thermionic electron emitter has been demonstrated [1]. Using field emitter arrays (FEAs) would yield non-radioactive portable low power devices with fast switching capability. By combining FEAs with a vacuum-sealed housing and an electron transparent membrane window, such electron sources can be operated in an ambient pressure environment. Y1 - 2019 ER - TY - CHAP A1 - Berndt, Dominik A1 - Lindner, Matthias A1 - Schreiner, Rupert A1 - Pipa, Andrei V. A1 - Hink, Rüdiger A1 - Brandenburg, Ronny A1 - Foest, Rüdiger A1 - Geils, Judith A1 - Sander, Aljoscha A1 - Hoffmann, Florian A1 - Matz, Daniel A1 - Baars, Albert A1 - Kesel, Antonia A1 - Max, Alexander A1 - Caspari, Ralf T1 - Realization of Multifunctional Surfaces Containing MEMS-based DBD Plasma Actuators and Biomimetic Structures for Flow Manipulation T2 - AIAA Aviation 2019 Forum, 2019, Dallas Y1 - 2019 U6 - https://doi.org/10.2514/6.2019-2999 PB - American Institute of Aeronautics and Astronautics, Inc ER - TY - CHAP A1 - Prommesberger, Christian A1 - Langer, Christoph A1 - Schreiner, Rupert T1 - Stable and low noise field emission from single p-type Si-tips T2 - International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan N2 - Single gated p-type Si-tips with two different tip radii were fabricated. An emission current of 2.40 μA was measured for the sharp-edged tip at a voltage of 170 V. In contrast, a stable and reproducible emission behavior was observed with an increased tip radius resulting in a pronounced saturation region between 90 V and 150 V, but merely an emission current of 0.55 μA at 150 V. More remarkable is the stable emission behavior with fluctuation of ± 4 % during a measurement period of 30 minutes. The integral emission current in a homogeneous tip array (16 emitters) showed nearly the same I-V characteristics compared to the single tip and is therefore, most dominated by only a stable single tip in the array. KW - field emission KW - p-type Si-tips KW - gate-electrode KW - emission stability KW - low current fluctuations Y1 - 2018 U6 - https://doi.org/10.1109/IVNC.2018.8520018 PB - IEEE ER - TY - CHAP A1 - Lindner, Matthias A1 - Berndt, Dominik A1 - Prommesberger, Christian A1 - Langer, Christoph A1 - Schreiner, Rupert T1 - Field emission assisted micro plasma discharges at vacuum and atmospheric pressures T2 - 31st International Vacuum Nanoelectronics Conference (IVNC), 2018, Kyoto, Japan N2 - Spatially confined non-equilibrium plasmas at vacuum and atmospheric pressure in the dimensions from a few microns to one millimeter are a promising approach to the generation and maintenance of stable glow discharges. The realization of these micro-discharges or micro-plasmas enable more accurate investigations in the field of micro plasma research. We report on field emission assisted micro plasmas excited by an alternating current with frequencies up to 1 kHz. Due to the field enhancement caused by an array of Si nano-tip structures the ignition voltage of stable plasma discharges can be reduced by 30%. Y1 - 2018 U6 - https://doi.org/10.1109/IVNC.2018.8520181 ER - TY - CHAP A1 - Berndt, Dominik A1 - Lindner, Matthias A1 - Tschurtschenthaler, Karl A1 - Langer, Christoph A1 - Schreiner, Rupert T1 - Miniaturized Plasma Actuator Flow Measurements by MEMS-Based Thermal Conductivity Sensors T2 - MDPI Proceedings of Eurosensors 2018, 9-12 September, Graz N2 - The gasflow created by a minaturized dielectric barrier discharge (DBD) plasma actuator is measured by a MEMS-based thermal conductivity gas sensor giving an indication of flow velocity and flow direction. The possiblity of several sensors in a small area gives a far better accuracy of local flow phenomena compared to conventional sensors. This is important for a better understanding of plasma- induced flow characteristics. KW - thermal conductivity sensors; plasma actuators; surface hotfilms; sensors for aerospace Y1 - 2018 U6 - https://doi.org/10.3390/proceedings2130939 VL - Vol.13 IS - 2 ER - TY - CHAP A1 - Bierl, Rudolf A1 - Boehm, M. A1 - Fraunhoffer, Judith A1 - Gardeia, Armin A1 - Mottok, Jürgen A1 - Schneider, Ralph A1 - Streubel, J. T1 - “Regensburger Modell zu den P-Seminaren” – Ein Konzept zur Gestaltung der Schnittstelle Gymnasium – Hochschule und zur Praxis einer kooperativen Lehr-Lern-Didaktik für Informationstechnik T2 - 3rd Embedded Software Engineering Congress, 7. bis 9. Dezember, Sindelfingen Y1 - 2010 PB - Vogel Business Media CY - Würzburg ER - TY - CHAP A1 - Edler, Simon A1 - Hansch, Walter A1 - Prommesberger, Christian A1 - Schreiner, Rupert T1 - Influence of adsorbates on the performance of a field emitter array in a high voltage triode setup T2 - International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan N2 - The influence of residual gas pressure on the characteristics of black-Silicon field emitter arrays in a high voltage triode setup is investigated. I-Vcharacteristics at different pressure levels show a decrease of emission current with rising pressure. This can be explained by an increase of the work function and charging of the emitter surface due to adsorbates. The initial characteristics can be restored by heating the FEA up to 110 °C during electron emission. This regeneration procedure enables an extension of the lifetime from about 20 h to 440 h at a residual gas pressure of 10 -5 mbar. KW - semiconductor field emission KW - field emitter array KW - silicon tips KW - emission current stability Y1 - 2018 U6 - https://doi.org/10.1109/IVNC.2018.8520214 PB - IEEE ER - TY - JOUR A1 - George, Wolfgang Michael A1 - Allert, R. A1 - Weber, Karsten T1 - Versorgung Sterbender im Krankenhaus Ein vom G-BA-Innovationsfonds gefördertes Projekt reduziert nicht indizierte Verlegungen JF - KU-Gesundheitsmanagement N2 - Würdevolles Sterben muss an jedem Ort möglich sein, auch im Krankenhaus, und hier nicht nur auf einer Palliativstation. Immer noch kommt es am Lebensende zu unnötigen, nicht dem Patientenwohl dienenden, Verlegungen vom Heim oder der eigenen Wohnung in das Krankenhaus, vom Krankenhaus bspw. in ein Hospiz oder innerhalb des Krankenhauses von einer Normal- auf die Intensivstation. Damit die Zahl vermeidbarer Verlegungen im Krankenhaus reduziert wird, wurden im Rahmen eines Projektes zur Versorgungsforschung (Avenue-Pal), gefördert über den Gemeinsamen Bundesausschuss aus dem Innovationsfonds des Bundes, Entscheidungshilfen erarbeitet. Y1 - 2021 SN - 2510-8409 VL - 90 SP - 24 EP - 27 PB - Mediengruppe Oberfranken - Fachverlage CY - Kulmbach ER - TY - JOUR A1 - Weigl, Stefan A1 - Feldmeier, Florian A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Photoacoustic detection of acetone in N2 and synthetic air using a high power UV LED JF - Sensors Actuators B Chemical N2 - The performance of a photoacoustic trace gas sensor for the detection of acetone in N2 and synthetic air is reported. The sensor system utilises an amplitude modulated UV LED. The light source has an emission maximum at 278 nm and a maximum CW output power of 300 mW according to the datasheet. Three different collimating and focusing approaches have been investigated to guide the highly divergent LED light into the acoustic resonator of the photoacoustic measurement cell. A 3D printed aluminium cell was designed to optimize light coupling by simultaneously minimizing the photoacoustic background signal generation. Hence, the diameter of the resonator was set to a comparable large diameter of 10 mm and the inner walls of the resonator were mirror polished. The additive manufacturing procedure allowed for integration of a spirally formed gas channel, enabling gas heating prior to detection. The sensor performance was investigated by measuring acetone in N2 and synthetic air at different concentrations. The UV LED current was set to 86 % of the maximum value according to the datasheet of the light source in order to increase the lifetime and thermal stability. An Allan-Werle deviation analysis validates a stable sensor performance. The limit of detection (LoD) was determined at a 3σ noise level with a 10 s lock-in amplifier time constant by sampling data points over 20 s with a data acquisition rate of 5 Hz. LoDs of 80.8 ppbV and 19.6 ppbV were obtained for acetone in N2 and synthetic air, respectively. KW - Acetone detection KW - Photoacoustic spectroscopy KW - High power UV LED KW - UV LED collimation system KW - Acetone breath analysis Y1 - 2020 U6 - https://doi.org/10.1016/j.snb.2020.128109 N1 - Corresponding author at: Sensorik-Applikationszentrum (SappZ) der Ostbayerischen Technischen Hochschule Regensburg VL - 316 IS - August SP - 1 EP - 11 PB - Elsevier ER - TY - JOUR A1 - Berndt, Dominik A1 - Muggli, Josef A1 - Wittwer, Franz A1 - Langer, Christoph A1 - Heinrich, Stephan A1 - Knittel, Thorsten A1 - Schreiner, Rupert T1 - MEMS-based thermal conductivity sensor for hydrogen gas detection in automotive applications JF - Sensors and Actuators A: Physical N2 - Accurate detection of hydrogen gas in vehicle interiors is very important for the future of a fuel cell car. Since this type of gas is highly volatile and flammable, the measurement methods have to be very reliable and precise due to safety reasons. In this paper a thermal conductivity sensor for hydrogen gas detection is presented, exhibiting a lower detection limit of 2000 ppm hydrogen in laboratory air. The sensor element is realized by micro-fabrication techniques on silicon wafers. The heated filament is exposed by a selective wet etching process creating a micro-hotplate on a thin membrane. In order to minimize power consumption, the sensor is operated in pulsed mode. Hydrogen gas detection was carried out using a synthetic gas testbench. Measurements of hydrogen contents ranging from 0% to 4% with an increment of 0.5% were successfully performed for ambient gas temperatures between -15°C and 84°C. Including humidity, high moisture contents have the greatest influence on thermal conductivity. This was predicted in theoretical investigations and confirmed in experiments. For evaluation, both the change in resistance ΔR as well as the time constant τ were taken as sensor output. For both quantities, the previously established theoretical relationship with thermal conductivity could be confirmed. Y1 - 2020 U6 - https://doi.org/10.1016/j.sna.2019.111670 VL - 305 IS - April PB - Elsevier ER - TY - JOUR A1 - Weigl, Stefan A1 - Wittmann, Elisabeth A1 - Rück, Thomas A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Effects of ambient parameters and cross-sensitivities from O2, CO2 and H2O on the photoacoustic detection of acetone in the UV region JF - Sensors Actuators B Chemical N2 - We present a sensitive UV LED photoacoustic setup for the detection of gaseous acetone and discuss its applicability towards breath analysis. We investigated the performance of the sensor for low acetone concentrations down to 0.1 parts per million (ppmV). The influences of temperature, flow, pressure, optical power and LED duty cycle on the measured signal have been examined. To gain a better understanding of the different effects on the photoacoustic signal, correlation analysis was applied and feature importance was determined using a large measured dataset. Furthermore, the cross-sensitivities towards O2, CO2 and H2O have been studied extensively. Finally, the sensor’s performance to detect acetone between 0.1–1 ppmV within gas mixtures simulating breath exhale conditions has been investigated, too. With a limit of detection (LoD) of 12.5 parts per billion (ppbV) (3σ) measured under typical breath exhale gas mixture conditions, the sensor demonstrated a high potential for the application of acetone detection in human breath analysis. KW - Acetone detection KW - Photoacoustic spectroscopy KW - High power UV LED KW - Cross-sensitivities KW - Acetone breath analysis Y1 - 2021 U6 - https://doi.org/10.1016/j.snb.2020.129001 SN - 0925-4005 N1 - Corresponding authors: Stefan Weigl, Elisabeth Wittmann, Thomas Rück, Rudolf Bierl, Frank-Michael Matysik N1 - Corrigendum to “Effects of ambient parameters and cross-sensitivities from O2, CO2 and H2O on the photoacoustic detection of acetone in the UV region” [Sens. Actuators B: Chem. 328 (February 2021) (2020) 129001]; https://doi.org/10.1016/j.snb.2020.129392 IS - 328 PB - Elsevier ER - TY - CHAP A1 - Hausler, Peter A1 - Jobst, Simon A1 - Fischer, Johannes A1 - Roth, Carina A1 - Bierl, Rudolf T1 - Homogeneous Light Source for Surface Plasmon Resonance Imaging T2 - PHOTOPTICS 2020: proceedings of the 8th International Conference on Photonics, Optics and Laser Technology, Valletta, Malta, February 27-29, 2020 N2 - We describe how to build a homogeneous light source for Surface Plasmon Resonance Imaging (SPRi) which mainly finds its applications in pharmaceutical screening and biotechnology so far. SPR spectroscopy is a label-free, non-destructive and highly sensitive measurement principle for detecting changes in the refractive index in close vicinity of a gold surface. A transfer of this technology to a miniaturized sensor will broaden the range of possible applications. Commercial SPR assays are mainly working with a small number of sensing spots. In contrast, the SPR imaging system shown here will allow the use of an array of many sensing spots. In combination with chemical receptors designed as an artificial nose or an electronic tongue, the simultaneous detection of many analytes is envisioned. So far, lasers or other inhomogeneous light sources were used to illuminate the sensing surface, which is decreasing the systems sensitivity. We show a compact ( 300mm2) homogeneous top hat profile. The combination of a high bit-resolution camera with our new light source enables a reflectivity based surface plasmon resonance imaging system with a high refractive index unit (RIU) resolution. KW - Surface Plasmon Resonance Spectroscopy KW - Sensor KW - SPR-imaging KW - Miniaturization KW - Micro-opto-electro-mechanical Systems Y1 - 2020 U6 - https://doi.org/10.5220/0009168701630167 SP - 163 EP - 167 PB - SCITEPRESS - Science and Technology Publications ER - TY - CHAP A1 - Gschossmann, Andreas A1 - Jobst, Simon A1 - Mottok, Jürgen A1 - Bierl, Rudolf T1 - A Measure of Confidence of Artificial Neural Network Classifiers T2 - ARCS Workshop 2019; 32nd International Conference on Architecture of Computing Systems, 20-21 May 2019, Copenhagen, Denmark N2 - Confidence in results of an Artificial Neural Networks (ANNs) is increased by preferring to reject data, that is not trustful, instead of risking a misclassification. For this purpose a model is proposed that is able to recognize data, which differs significantly from the training data, during inference. The proposed model observes all activations of the hidden layers, as well as input and output layers of an ANN in a grey-box view. To make ANNs more robust in safety critical applications, this model can be used to reject flawed data, that is suspected to decrease the accuracy of the model. If this information is logged during inference, it can be used to improve the model, by training it specifically with the missing information. An experiment on the MNIST dataset is conducted and its results are discussed. Y1 - 2019 UR - https://ieeexplore.ieee.org/document/8836211 SP - 153 EP - 157 PB - VDE-Verlag CY - Berlin ER - TY - CHAP A1 - Romano, Marco A1 - Micklitz, Matthias A1 - Olbrich, Florian A1 - Bierl, Rudolf A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Experimental investigation of damping properties of unidirectionally and fabric reinforces plastics by the free decay method T2 - Proceeding of the 15th International Materials Symposium (IMSP´2014), Pamukkale University (Denizli, Turkey), 15./17. October 2014 Y1 - 2014 SP - 665 EP - 679 ER - TY - CHAP A1 - Haug, Sonja A1 - Vernim, Matthias T1 - Ausländische Hochschulabsolventen auf dem Arbeitsmarkt in Regensburg BT - Eine Auswertung der Befragung "Integration in Regensburg" T2 - Tagung "Beschäftigung ausländischer Hochschulabsolventen" Bundesamt für Migration und Flüchtlinge, 15.05.2014, Nürnberg Y1 - 2014 ER - TY - CHAP A1 - Silberbauer, Theodor A1 - Lindner, Matthias A1 - Schreiner, Rupert T1 - Charakterisierung der dielektrischen Barrierenentladung von Mikroplasmaaktuatoren in Abhängigkeit der Substratdicke T2 - Intelligente Systeme und ihre Komponenten: Forschung und industrielle Anwendung : Fachbeiträge 2. Symposium Elektronik und Systemintegration ESI 2020 Y1 - 2020 UR - https://nbn-resolving.org/urn:nbn:de:bvb:860-opus4-2130 N1 - Die Fachtagung, geplant für den 01. April 2020 an der Hochschule Landshut, wurde aufgrund der Corona-Pandemie abgesagt, die eingereichten Fachbeiträge im Tagungsband 2. Symposium Elektronik und Systemintegration ESI 2020: "Intelligente Systeme und ihre Komponenten: Forschung und industrielle Anwendung" veröffentlicht. Hrsg.: Artem Ivanov, Marc Bicker und Peter Patzelt. Hochschule Landshut, 2020, ISBN 978-3-9818439-4-1. SP - 64 EP - 72 CY - Landshut ER - TY - INPR A1 - Siders, Craig A1 - Cavalleri, Andrea A1 - Toth, Csaba A1 - Squier Jeff A., A1 - Barty, C. P. J. A1 - Wilson, K. R. A1 - Sokolowski-Tinten, Klaus A1 - von der Linde, Dietrich A1 - Kammler, Martin A1 - Horn- von Hoegen, Michael T1 - Ultrafast Nonthermal Melting of Femtosecond-laser-irradiated Germanium Measured by Ultrafast X-ray Diffraction N2 - Many fundamental processes in nature, such as chemical reactions and phase transitions involve rearrangement of the constituent atoms. Such changes cannot be directly measured with visible light and occur transiently on time-scales comparable with the natural oscillation periods of atoms (femtoseconds to picoseconds). We present experiments on Ge-111 films irradiated with 100-fs 800-nm light pulses and probed by a time-delayed sub-ps x-ray pulse at 8 keV. After excitation of a dense electron-hole plasma within the 160-nm film, the ultrafast pathway of lattice disordering is measured as a function laser fluence. For close-to-threshold irradiation, inhomogeneous thermal melting, occurring via surface nucleation of the liquid phase and growth into the bulk determines the dynamics of the solid-to-liquid phase transition. For excitation at about twice the melting threshold, a nonthermal pathway, starting from a highly excited cold solid and relaxing into a hot liquid causes ultrafast melting. At long time delays, nearly perfect recrystallization of a (111) crystal is observed. Y1 - 2000 UR - https://www.researchgate.net/publication/252159566_Ultrafast_Nonthermal_Melting_of_Femtosecond-laser-irradiated_Germanium_Measured_by_Ultrafast_X-ray_Diffraction ER - TY - INPR A1 - Steffens, Oliver T1 - Nomograms for Quadratic and Cubic Equations Y1 - 2024 U6 - https://doi.org/10.13140/RG.2.2.12187.48168 ER - TY - JOUR A1 - Krysztof, Michał A1 - Miera, Paweł A1 - Urbański, Paweł A1 - Grzebyk, Tomasz A1 - Hausladen, Matthias A1 - Schreiner, Rupert T1 - Integrated silicon electron source for high vacuum microelectromechanical system devices JF - Journal of Vacuum Science & Technology B N2 - The article presents the process of developing a silicon electron source designed for high-vacuum microelectromechanical system (HV MEMS) devices, i.e., MEMS electron microscope and MEMS x-ray source. Technological constraints and issues of such an electron source are explained. The transition from emitters made of carbon nanotubes to emitters made of pure silicon is described. Overall, the final electron source consists of a silicon tip emitter and a silicon gate electrode integrated on the same glass substrate. The source generates an electron beam without any carbon nanotube coverage. It generates a high and stable electron current and works after the final bonding process of an HV MEMS device. KW - Materials Chemistry KW - Electrical and Electronic Engineering KW - Surfaces, Coatings and Films KW - Process Chemistry and Technology KW - Instrumentation KW - Electronic, Optical and Magnetic Materials Y1 - 2024 U6 - https://doi.org/10.1116/6.0003385 SN - 2166-2746 VL - 42 IS - 2 PB - AIP Publishing ER - TY - JOUR A1 - Schreiner, Rupert A1 - Naegele, Peter A1 - Körbl, M. A1 - Groning, A. A1 - Gentner, Jean-Louis A1 - Schweizer, Heinz C. T1 - Monolithically integrated tunable laterally coupled distributed-feedback lasers JF - Photonics Technology Letters N2 - A new method for fabrication of tunable InGaAsP-InP single-mode lasers without epitaxial overgrowth is reported. These devices show the advantage of a considerably simplified fabrication process compared to conventional tunable laser types. The lasers comprise an active Bragg reflector integrated with an uncorrugated separately pumped gain region. By adjusting the current through the Bragg reflector, the wavelength can be tuned between 1590.8 and 1595.2 nm. KW - Tunable circuits and devices KW - Optical coupling KW - Laser tuning KW - Etching KW - Pump lasers KW - Laser feedback KW - Optical device fabrication KW - Distributed feedback devices KW - Gratings KW - Fiber lasers Y1 - 2001 U6 - https://doi.org/10.1109/68.969880 VL - 13 IS - 12 SP - 1277 EP - 1279 PB - IEEE ER - TY - INPR A1 - Pangerl, Jonas A1 - Sukul, Pritam A1 - Rück, Thomas A1 - Fuchs, Patricia A1 - Weigl, Stefan A1 - Miekisch, Wolfram A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - An Inexpensive Uv-Led Photoacoustic Based Real-Time Sensor-System Detecting Exhaled Trace-Acetone N2 - In this research we present a low-cost system for breath acetone analysis based on UV-LED photoacoustic spectroscopy. We considered the end-tidal phase of exhalation, which represents the systemic concentrations of volatile organic compounds (VOCs) – providing clinically relevant information about the human health. This is achieved via the development of a CO2-triggered breath sampling system, which collected alveolar breath over several minutes in sterile and inert containers. A real-time mass spectrometer is coupled to serve as a reference device for calibration measurements and subsequent breath analysis. The new sensor system provided a 3σ detection limit of 6.4 ppbV and an NNEA of 1.1E-9 Wcm-1Hz-0.5. In terms of the performed breath analysis measurements, 12 out of 13 fell within the error margin of the photoacoustic measurement system, demonstrating the reliability of the measurements in the field. KW - photoacoustic spectroscopy KW - real-time mass-spectrometry KW - breath analysis KW - acetone KW - UV-LED Y1 - 2024 U6 - https://doi.org/10.2139/ssrn.4724198 N1 - Der Aufsatz wurde peer-reviewed unter folgender DOI veröffentlicht: https://doi.org/10.1016/j.pacs.2024.100604 PB - Elsevier ER - TY - RPRT A1 - Steffens, Oliver A1 - Neuleitner, Nikolaus T1 - Einfluss der Wärmespeicherfähigkeit von Massivbauteilen in der Gebäudehülle und im Inneren von Gebäuden auf Energiebedarf und Behaglichkeit BT - Gutachterliche Stellungsnahme Y1 - 2016 ER - TY - CHAP A1 - Buchner, Philipp A1 - Kaiser, Alexander A1 - Hausladen, Matthias A1 - Bartl, Mathias A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Silicon Nanowire Field Emitters with Integrated Extraction Gates Using Benzocyclobutene as an Insulator T2 - 37th International Vacuum Nanoelectronics Conference (IVNC), 15-19 July 2024, Brno, Czech Republic N2 - We are continuously improving the performance of our field emission electron sources. In this work a geometrically optimized design of electron sources with silicon nanowire field emitters on pillars was fabricated. This new design increased the packing density of the emitters by using a hexagonal arrangement of the pillars and a pillar spacing of 40 µm. Benzocyclobutene was used as the insulator material for an integrated (Cr/Ni) extraction gate. A modified fabrication process for the field emitters further improved reproducibility and reliability. An emission current of about 0.4 mA was measured for 30 minutes at an extraction voltage of 250 V and an anode voltage of 500 V. Electron transmission through the gate reached almost 100%. Y1 - 2024 U6 - https://doi.org/10.1109/IVNC63480.2024.10652314 SP - 1 EP - 2 PB - IEEE ER - TY - JOUR A1 - Berndt, Dominik A1 - Muggli, Josef A1 - Heckel, Robert A1 - Rahiman, Mohd Fuad A1 - Lindner, Matthias A1 - Heinrich, Stephan A1 - Plöchinger, Heinz A1 - Schreiner, Rupert T1 - A Robust Miniaturized Gas Sensor for H₂ and CO₂ Detection Based on the 3ω Method JF - Sensors N2 - Gas concentration monitoring is essential in industrial or life science areas in order to address safety-relevant or process-related questions. Many of the sensors used in this context are based on the principle of thermal conductivity. The 3ω-method is a very accurate method to determine the thermal properties of materials. It has its origin in the thermal characterization of thin solid films. To date, there have been very few scientific investigations using this method to determine the thermal properties of gases and to apply it to gas measurement technology. In this article, we use two exemplary gases (H2 and CO2) for a systematical investigation of this method in the context of gas analysis. To perform our experiments, we use a robust, reliable sensing element that is already well established in vacuum measurement technology. This helix-shaped thin wire of tungsten exhibits high robustness against chemical and mechanical influences. Our setup features a compact measurement environment, where sensor operation and data acquisition are integrated into a single device. The experimental results show a good agreement with a simplified analytical model and FEM simulations. The sensor exhibits a lower detection limit of 0.62% in the case of CO2, and only 0.062% in case the of H2 at an excitation frequency of 1 Hz. This is one of the lowest values reported in literature for thermal conductivity H2 sensors. KW - 3ω-method KW - CO2 sensor KW - H2 sensor KW - thermal gas sensor Y1 - 2022 U6 - https://doi.org/10.3390/s22020485 N1 - Corresponding author: Dominik J. Berndt VL - 22 IS - 2 SP - 1 EP - 17 PB - MDPI CY - Basel ER - TY - JOUR A1 - Steininger, Peter A1 - Gaderer, Matthias A1 - Steffens, Oliver A1 - Dawoud, Belal T1 - Experimental and Numerical Study on the Heat Transfer Characteristics of a Newly-Developed Solar Active Thermal Insulation System JF - Buildings N2 - A newly-developed solar active thermal insulation system (SATIS) is introduced with the main objective to accomplish a highly-dependent total solar transmittance on the irradiation angle. SATIS is also designed to obtain the maximum transmittance at a prescribed design irradiation angle and to reduce it remarkably at higher irradiation angles. A purely mineral thermal insulation plaster with micro hollow glass spheres is applied to manufacture the investigated SATIS prototype. Light-conducting elements (LCEs) have been introduced into SATIS and suitable closing elements have been applied. The SATIS prototype has been investigated both experimentally and numerically. It turned out that the contributions of conduction, radiation and convection to the effective thermal conductivity of SATIS, without the closing elements (49 mWmK), amount to 86.2%, 13.2% and 0.6%, respectively. The angle-dependent short-wave radiation exchange within the LCE has been investigated via ray tracing. At the incidence angle of 19% (design angle), 27% of the radiation within the LCE is absorbed by the absorber plate, resulting in measured and computed total solar energy transmittances of 11.2%/11.7%, respectively. For a typical summer irradiation angle of 60%, 98% of the incident radiation is absorbed by the surfaces at the entrance of the LCE. The corresponding total solar energy transmittance amounts to 2.9%. KW - angle-dependent total solar energy transmittance KW - effective thermal conductivity KW - experimental investigation KW - numerical simulation KW - ray tracing KW - solar active thermal insulation system (SATIS) Y1 - 2021 U6 - https://doi.org/10.3390/buildings11030123 N1 - Corresponding author: Belal Dawoud VL - 11 IS - 3 SP - 1 EP - 22 PB - MDPI ER - TY - JOUR A1 - Schloplocher, Paul Dragos A1 - Ettengruber, Stefan A1 - Steffens, Oliver T1 - Improvements for building-performance simulations by a comparative finite-element method analysis JF - Energy and Buildings N2 - This paper presents a method to improve building-performance simulations (BPS) by the comparison and analysis of different approaches based on finite-element method (FEM) models. The lumped parameter method (LPM) is used in several BPS programs and tools. It has the advantage of fast computing times and comparably good accuracy for thermal and energy loads. With the help of detailed FEM simulations, it is possible to further improve the degree of detail and accuracy while maintaining the high simulation speed. In this work, we compare time-dependent results for local temperatures in a generic reference room within a given periode of time. In a second step, the differences between the models with respect to various physical effects are analyzed and used to introduce additional equations into the LPM model in order to improve its accuracy. Thus, we discuss potentials for improvement for BPS and demonstrate a method of a practical implementation. The results show minor differences of less than 0.1 K for radiation and heat transfer, so their level of detail in BPS is appropriate. In these terms, no improvements were pursued within the work. However, the FEM simulation is capable of calculating the internal convective heat transfer and thermal bridges more accurately due to the use of computational fluid dynamics (CFD) and the geometrically precise representation of the FEM model. Here, deviations of up to 1 K in room temperature (convective heat transfer) and up to 0.5 K in wall temperatures (thermal bridges) were pointed out. By improving the LPM with equations obtained from the FEM, these deviations can be reduced to less than 0.2 K, which is a considerable improvement in accuracy. KW - Lumped parameter model KW - Finite-element method KW - Building performance simulation Y1 - 2023 U6 - https://doi.org/10.1016/j.enbuild.2022.112563 N1 - Corresponding author: Dragos Paul Schoplocher VL - 278 SP - 1 EP - 12 PB - Elsevier ER - TY - JOUR A1 - Steffens, Oliver A1 - Schlösser, Tilman A1 - Rotter, Peter A1 - Ensslin, Klaus A1 - Suhrke, Michael A1 - Kotthaus, Jörg A1 - Rössler, Ulrich A1 - Holland, M. T1 - From the two-dimensional electron gas to antidot superlattices: Magnetoresistance effects in the transition regime JF - Journal of Physics: Condensed Matter N2 - Magnetoresistance measurements and theoretical calculations for two-dimensional electron systems under a perpendicular magnetic field are presented which illuminate transport effects due to a periodic electrostatic potential modulation. We focus on features arising from the resolution of the magnetic miniband structure which are beyond the perturbative regime governed by the dispersion of Landau bands. Our non-perturbative quantum-mechanical calculations reveal that the dispersion of individual minibands is responsible for the complicated behaviour of the magnetoresistance in the regime of intermediate modulation strength. In particular, the interplay between miniband and scattering contributions to the conductivity leads to an almost structureless magnetoresistance in this regime followed by the formation of antidot peaks due to the miniband conductivity. Y1 - 1998 U6 - https://doi.org/10.1088/0953-8984/10/17/016 SN - 0953-8984 VL - 10 IS - 17 SP - 3859 EP - 3872 ER - TY - JOUR A1 - Steffens, Oliver A1 - Suhrke, Michael A1 - Rössler, Ulrich T1 - Shell structure and exchange-related spin effects for quantum dots in a magnetic field JF - Physica B N2 - Ground-state calculations based on current spin density-functional theory for circular parabolic quantum dots are presented which reveal interesting spin effects in dependence on an external magnetic field: Hund's first rule (well-known from atomic physics for zero magnetic field) is related to the level occupancy near the Fermi energy and determines the spin configuration of the ground state in finite magnetic field. Consequently, the addition spectrum of the quantum dot exhibits a specific non-monotonous dependence on magnetic field, which is visible in recent quantum transport experiments. KW - Quantum dot KW - Current spin density-functional theory KW - Exchange correlation Y1 - 1998 U6 - https://doi.org/10.1016/S0921-4526(98)00557-2 VL - 256-258 SP - 147 EP - 151 ER - TY - JOUR A1 - Steffens, Oliver A1 - Rössler, Ulrich A1 - Suhrke, Michael T1 - Generalized Hund's rule in the addition spectrum of a quantum dot JF - EPL (Europhysics Letters) N2 - We report on ground-state calculations based on current-spin density-functional theory for circular parabolic quantum dots. Hund's first rule, well-known from atomic physics, applies not only at zero magnetic field; analogous rules, related to the level occupancy near the Fermi energy, determine the spin configuration of the ground state in finite magnetic field. Consequently, the addition spectrum of the quantum dot exhibits a specific non-monotonous dependence on magnetic field. We discuss our results with focus on recent experiments which may already contain indications of this new feature. Y1 - 1998 U6 - https://doi.org/10.1209/epl/i1998-00276-4 VL - 42 IS - 5 SP - 529 EP - 534 ER - TY - JOUR A1 - Steffens, Oliver A1 - Suhrke, Michael A1 - Rössler, Ulrich T1 - Spontaneously-broken time-reversal symmetry in quantum dots JF - EPL (Europhysics Letters) N2 - We present current-spin density-functional calculations for circular parabolic quantum dots in zero magnetic field. We find the possibility for broken time-reversal symmetry via exchange correlation with spontaneously induced orbital currents. For certain electron numbers, this results in new current textures which give rise to a finite magnetization even for ground states with vanishing total angular momentum. Y1 - 1998 U6 - https://doi.org/10.1209/EPL/I1998-00460-0 SN - 1286-4854 VL - 44 SP - 222 EP - 228 ER - TY - JOUR A1 - Schreiner, Rupert A1 - Körbl, M. A1 - Gräbeldinger, H. A1 - Gentner, Jean-Louis A1 - Schweizer, H. T1 - Laterally gain-coupled 1.57 [micro sign]m DFB lasers with chromium surface grating and self-aligned Ti/Pt/Au ohmic contact JF - Electronics Letters N2 - A simple method for fabricating gain coupled DFB lasers with lateral surface chromium Bragg gratings and self-aligned low capacitance ohmic contacts is reported. These InGaAsP/InP lasers show monomode emission with a sidemode suppression ratio of 40 dB. For 243 µm long devices a continuous wave threshold current of 17 mA was measured at room temperature. KW - Bragg gratings KW - platinum KW - chromium KW - ohmic contacts KW - titanium KW - distributed feedback lasers KW - gold Y1 - 2000 U6 - https://doi.org/10.1049/el:20000500 SN - 0013-5194 VL - 36 IS - 7 SP - 636 EP - 637 PB - The Institution of Engineering and Technology, IET ER - TY - JOUR A1 - Rück, Thomas A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - NO2 trace gas monitoring in air using off-beam quartz enhanced photoacoustic spectroscopy (QEPAS) and interference studies towards CO2, H2O and acoustic noise JF - Sensors and Actuators B: Chemical N2 - We present the development and characterization as well as comprehensive interference studies of a photoacoustic NO2 trace gas detection system. The system is based on an off-beam quartz enhanced photoacoustic scheme (off-beam QEPAS) and signal generation was initiated by amplitude modulating a low-cost diode laser emitting at 450 nm. The QEPAS sensor element features double-resonant amplification, still it is only ∼ 5 × 5 × 2.5 mm in size. The individual and combined resonance characteristics were investigated and specified to 52 dB amplification, adding up 15 dB acoustic- and 37 dB mechanical-resonance amplification. The linearity of the photoacoustic signal dependency on the analyte concentration was verified from 200 ppbV to 100 ppmV NO2 in synthetic air. The detection limit (3σ) was determined to 1.8 ppbV using a lock-in time constant of 10 s and an averaging time of 20 s. The normalized noise equivalent absorption coefficient was specified to 2.5·10−8 W cm−1 Hz−0.5. The stability of the signal was investigated over time and a slight drift by 1‰ was observed after 30 min without temperature stabilizing the photoacoustic cell (PAC). Noise analysis was performed by means of Allan deviation and the inverse dependency of response time and precision of the system on the lock-in time constant was outlined. We performed interference analyses towards N2, O2, CO2, H2O and acoustic noise, respectively. Although neither spectral interferences nor losses due to slow NO2 VT-relaxation were observed, O2 was identified to cause a 15% signal drop due to VVNO2-O2-relaxation. Changing H2O concentrations were found to cause acoustic detuning, which cannot be compensated by adjusting the frequency of modulation, because of the double-resonant feature of the PAC. However, alternative approaches of compensation were discussed. Finally, we carried out heavy traffic noise simulations and determined the QEPAS setup to be 46 times less susceptible towards ambient noise compared to standard microphone-based photoacoustic setups. Y1 - 2018 U6 - https://doi.org/10.1016/j.snb.2017.09.039 VL - 255 IS - Part 3, February SP - 2462 EP - 2471 PB - Elsevier ER - TY - JOUR A1 - Rück, Thomas A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Development and characterization of a laboratory setup for photoacoustic NO2 determination based on the excitation of electronic 2B2 and 2B1 states using a low-cost semiconductor laser JF - Sensors and Actuators A: Physical N2 - This work gives a detailed characterization of a laboratory setup for photoacoustic NO2 trace gas detection at the ppb level. The signal generation is based on the excitation of electronic 2B2 and 2B1 states using a low-cost semiconductor laser emitting at 450 nm. An acoustic resonator was used for signal amplification and the modulation frequency of the laser was determined to 3395 Hz in order to gain maximum signal amplification. The quality of resonant amplification was determined to 7.9. The gas samples were NO2 calibration gases diluted with pure nitrogen. The signal-to-noise ratio (SNR) dependency on the flow rate Q and the lock-in time constant τLIA was investigated, respectively, and the optimum values were specified to Q = 500 mL/min and τLIA = 2 s. In case of ambient noise, increasing τLIA to 10 s was evaluated as sufficient for SNR preservation. The noise level was measured in the absence of NO2 and it was determined to be composed of 51% electronic noise and 49% gas flow noise. With the analyte concentration ranging from 300 ppbV to 100 ppmV, the linear dependency of the photoacoustic amplitude on the NO2 concentration was specified, the sensitivity was determined to 110 μV/ppmV and the maximum measurement error was calculated to ±0.8%. The detection limit was determined to 2.0 ppbV. Furthermore, the stability of the signal was investigated and a maximum drift of ±1% was observed within a measuring period of 30 min. The response time τ90 was specified to 58 s. All results considered, this photoacoustic measuring system, which is based on low-cost signal generation and detection units, provides an excellent basis in view of developing a portable device for photoacoustic trace gas detection. Y1 - 2017 U6 - https://doi.org/10.1016/j.sna.2017.03.024 VL - 258 SP - 193 EP - 200 PB - Elsevier CY - Amsterdam, Niederlande ER - TY - JOUR A1 - Rück, Thomas A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Low-cost photoacoustic NO2 trace gas monitoring at the pptV-level JF - Sensors and Actuators A: Physical N2 - We present the development and the characterization of a photoacoustic NO2 trace gas detection system. The system is based on the implementation of low-cost components, i.e. a mass-produced blue diode laser and a standard MEMS microphone which is commonly built into smartphones, for example. An optimized cell design was realized by means of 3D printing. The linearity of the photoacoustic signal dependency on the analyte concentration was verified from 200 ppbV to 100 ppmV NO2. The detection limit (1σ) was determined to 33 pptV and the normalized noise equivalent absorption coefficient was calculated to 7.0 ∙ 10−10 W cm−1 Hz−1/2. The dynamic range of the system was verified to be linear over three magnitudes of order and the sensitivity was calculated to 814 μV/ppmV. The system was characterized in view of optimal operating parameters, i.e. lock-in time constant τLIA and total mass flow rate, optical performance and signal stability. The mass flow dependend response time of the system was specified to 19 s and an idealized step response to a quasi-Heaviside step function was quantified as a function of τLIA. The quality factor of acoustic resonance was determined to 21.9 and an empirical expression regarding acoustic node shifting is provided. The expression takes into account the radius of the resonator pipe and the radius of the hole, which was drilled into the pipe for microphone coupling. Furthermore, we studied the cross-sensitivity of the photoacoustic signal towards H2O and CO2, respectively. Y1 - 2017 U6 - https://doi.org/10.1016/j.sna.2017.06.036 VL - 263 SP - 501 EP - 509 PB - Elsevier CY - Amsterdam, Niederlande ER - TY - GEN A1 - Weigl, Stefan A1 - Matysik, Frank-Michael A1 - Bierl, Rudolf T1 - Development of a sensor system for analysis of human breath exhale T2 - BayWISS Herbstakademie 2018, Plankstetten N2 - Atemgasanalyse ist ein junges und vielversprechendes Feld im Bereich der diagnostischen Medizin. Der Ansatz verspricht einfach zugängliche und leicht wiederholbare Probennahme die zum einen non-invasiv ist und zugleich Rückschlüsse auf Vorgänge im menschlichen Körper und bspw. dessen Gesundheitszustand zulässt. Seit Ende des 20. Jahrhunderts gibt es Massenspektrometer die es ermöglicht haben mehrere Tausend verschiedene Stoffe in der Ausatemluft nachzuweisen. Diese Technologien verbessern sich stetig und ermöglichen es die Vorgänge und Zusammenhänge zwischen Zusammensetzung der Ausatemluft und systemischen Prozessen besser zu verstehen. Die bei Studien mit Massenspektrometern ermittelten Biomarker, deren qualitative und quantitative Detektion Gesundheitsdiagnosen ermöglichen, haben aber noch nicht den Weg in den klinischen Alltag gefunden. Das Problem sind meistens die hohen Anschaffungskosten, komplizierte Datenauswertung und zumeist geringe Verfügbarkeit und Immobilität dieser Messgeräte. Die photoakustische Spektroskopie ist eine selektive und hochsensitive Messmethode, die es ermöglichen soll den Biomarker „Aceton“, der grundsätzlich die Metabolisierung von Fetten widerspiegelt, schnell und reproduzierbar quantitativ zu detektieren. Dabei müssen Hindernisse wie Querempfindlichkeiten, ausgelöst durch die komplexe Zusammensetzung der Messmatrix Atemgas, bei gleichzeitig kleine Aceton Konzentrationen (200-800 parts-per-billion) überwunden werden. Verschiedene Wellenlängenbereiche mit unterschiedlichen Lichtquellen, akustisch resonante sowie innovative Messzellendesigns und anspruchsvolle Datenauswertung mittels komplexer Algorithmik sind nötig um das Ziel, die Entwicklung eines kompakten, günstigen und zuverlässigen Acetonsensors, zu erreichen. Y1 - 2018 ER - TY - CHAP A1 - Roth, Carina A1 - Hausler, Peter A1 - Bierl, Rudolf T1 - Einbindung eines 2D-Photodetektors in einen hochintegrierten SPR-Imaging-Sensor T2 - 118. Jahrestagung der deutschen Gesellschaft für angewandte Optik (DGaO), 6.-10. Juni 2017, Dresden N2 - Mit der Oberflächenplasmonenresonanzspektroskopie (SPR) können Brechungsindexänderungen eines Analyten von bis zu 10-6 RIU detektiert werden. Das SPR-Imaging bietet heute gegenüber der konventionellen SPR-Analyse die Möglichkeit, mehrere einzelne Messungen parallel durchführen zu können. Mit Hilfe eines zweidimensionalen Sensorchips und einer leistungsfähigen Boardlevelkamera können die Abbildungen des Chips direkt an einen Rechner übertragen und dort verarbeitet werden. Aufgrund unterschiedlicher Winkelstellungen und der Geometrie des Aufbaus entstehen Stauchungen und Streckungen des abgebildeten Sensorchips, die mit verschiedenen Ansätzen aus der Bildverarbeitung ausgeglichen werden, um die Bilder miteinander vergleichen zu können. Zudem wird die Güte der Referenz- und Messbereiche des Chips bestimmt. Diese Algorithmen sind nur möglich aufgrund der heutigen, leistungsfähigen Rechner und der immer größer werdenden Durchsatzraten der Kameras. Dabei kommt in dieser Anwendung der relativ neue Kamerastandard USB3 Vision zum Einsatz. Dieser zeichnet sich zusätzlich durch das Plug and Play und seinen Standardstecker, der an (fast) jedem Rechner vorhanden ist, aus. KW - Bildverarbeitung KW - Messtechnik KW - Optische Informationsverarbeitung Y1 - 2017 ER - TY - CHAP A1 - Zhou, Qi A1 - Landgraf, Ferdinand A1 - Rück, Thomas A1 - Bierl, Rudolf T1 - Resonance frequency tuning and process design of a micromechanical capacitive cantilever in a photoacoustic trace-gas sensing device T2 - 7. MikroSystemTechnik Kongress "MEMS, Mikroelektronik, Systeme", 23.-25. Oktober 2017, München N2 - Photoacoustic spectroscopy is an efficient method to detect the concentration of trace gases with following advantages: short response time, high sensitivity, continuous and real-time monitoring and the option of miniaturization without the need of complex mirror-based multi-pass cell designs. A micromechanical cantilever is used as a key component in a two-part "Cantilever-Resonator" system that detects the weak photoacoustic signal. The resonance frequency of cantilever needs to be tuned to match the resonance frequency of resonator in order to achieve the maximum vibration amplitude of the "Cantilever-Resonator" system. This paper reports a post-fabrication method to tune the resonance frequency of cantilevers via focused ion beam (FIB) and a capacitive solution for the cantilever to transform the acoustic signal to electrical signal. Y1 - 2017 SN - 978-3-8007-4491-6 PB - VDE-Verlag CY - Berlin ER - TY - JOUR A1 - van der Weerd, Bastiaan A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Trends in Electrochemical Sensing of Blood Gases JF - Bioanalytical Reviews N2 - The monitoring of partial pressures of the blood gases carbon dioxide (pCO2) and oxygen (pO2) is of great importance in clinical diagnostics. The measure of pCO2 and pO2 provides essential information about the patient’s metabolism, gas exchange, ventilation, and acid–base homeostasis. The conventional electrochemical methods for clinical blood gas analysis are based on the potentiometric Severinghaus sensor for carbon dioxide and the amperometric Clark sensor for oxygen. These techniques are well established and are only shortly discussed in this overview. However, in recent years a variety of modifications of these classical sensor concepts and new approaches of electrochemical sensing of pCO2 and pO2 have been introduced. This review summarizes recent developments in this field and discusses the potential for future applications in clinical blood gas analysis. KW - Blood gas analysis KW - Noninvasive blood gas sensor KW - Electrochemical sensor KW - Clinical analysis Y1 - 2016 U6 - https://doi.org/10.1007/11663_2016_1 VL - 6 SP - 263 EP - 280 PB - Springer CY - Berlin ER - TY - CHAP A1 - Rück, Thomas A1 - Läpple, I. A1 - Bierl, Rudolf T1 - Photoakustische Spurengasanalytik von NO2 im ppt-Bereich (10^-12) bei Verwendung kostengünstiger Einzelkomponenten T2 - 7. MikroSystemTechnik Kongress "MEMS, Mikroelektronik, Systeme", 23.-25. Oktober 2017, München KW - Elektroniksystem KW - Industrie 4.0 KW - Mikrosystemtechnik KW - Mikrofluidik KW - Mikroaktorik Y1 - 2017 SN - 978-3-8007-4491-6 PB - VDE-Verlag CY - Berlin ER - TY - JOUR A1 - Zagler, Andreas A1 - Landgraf, Ferdinand A1 - Rück, Thomas A1 - Bierl, Rudolf T1 - Entwicklung eines mikromechanischen kapazitiven Schalldetektors im resonanten Betrieb für die photoakustische Spurengasanalyse JF - 7. MikroSystemTechnik Kongress "MEMS, Mikroelektronik, Systeme", 23.-25. Oktober 2017, München Y1 - 2017 PB - VDE-Verlag CY - Berlin ER - TY - CHAP A1 - Gaida, Peter A1 - Weigl, Stefan A1 - Rück, Thomas A1 - Bierl, Rudolf T1 - Portable photoakustische Messeinheit zur NO2 Detektion im Spurenbereich T2 - 7. MikroSystemTechnik Kongress "MEMS, Mikroelektronik, Systeme", 23.-25. Oktober 2017, München Y1 - 2017 SN - 978-3-8007-4491-6 PB - VDE-Verlag CY - Berlin ER - TY - CHAP A1 - Fischer, Johannes T1 - Miniaturisierter plasmonischer Sensor für das Monitoring von Weichmachern in Gewässerproben T2 - 7. MikroSystemTechnik Kongress "MEMS, Mikroelektronik, Systeme", 23.-25. Oktober 2017, München Y1 - 2017 SN - 978-3-8007-4491-6 PB - VDE-Verlag CY - Berlin ER - TY - GEN A1 - Hausler, Peter A1 - Roth, Carina A1 - Vitzthumecker, Thomas A1 - Fischer, Johannes A1 - Bierl, Rudolf T1 - Motionless SPR-angle scan with a miniaturized device T2 - Europtrode XIV, Naples, 25-28 March 2018 Y1 - 2018 ER - TY - CHAP A1 - Weigl, Stefan A1 - Gaida, Peter A1 - Rück, Thomas A1 - Bierl, Rudolf T1 - Portable Measurement Unit for NO2 Trace Gas Detection T2 - PHOTOPTICS 2018, 6th International Conference on Photonics, Optics and Laser Technology, 25 - 27 January 2018, Funchal Madeira Y1 - 2018 ER - TY - RPRT A1 - Unger, J. A1 - Rück, Thomas A1 - Landgraf, Ferdinand A1 - Bierl, Rudolf T1 - Herstellung und Analyse der Resonanzfrequenz eines MEMS Cantilever für das CEPAS Verfahren N2 - Diese Abhandlung beschreibt das Konzept eines mikroeletromechanischen Systems (MEMS), das im Messverfahren der cantilever enhanced photoacoustic spectroscopy (CEPAS) Verwendung finden soll. Es wird die Herstellung eines einseitig eingespannten Biegebalkens aus Silizium mittels deep reactiv ion etching (DRIE) beschrieben. Des Weiteren wird die Resonanzfrequenz dieses Cantilevers mit Hilfe Laservibrometertechnik untersucht. Die resultierenden resonanten Schwingungen 0.Ordnung werden mit den Ergebnissen einer vereinfachten theoretischen Näherung verglichen. Die Messergebnisse stehen in gutem Zusammenhang mit den theoretischen Werten. Solche Cantilever, die aus silicon on insula tor (SOI) Wafer angefertigt wurden, weisen bei einer Zielfrequenz ein mittlere Abweichung von Δf = 118±26Hz (bzw.Δf =0,76±0,17%) auf. Y1 - 2015 ER - TY - CHAP A1 - Holler, Sven A1 - Hausler, Peter A1 - Roth, Carina A1 - Bierl, Rudolf T1 - Gestapelte Au-Al-Au und Au-Ag-Au Schichten als aktive Schichten für die Oberflächenplasmonenresonanzspektroskopie T2 - 5. Landshuter Symposium Mikrosystemtechnik, März 2016 Y1 - 2016 SN - 978-3-9812696-9-7 SP - 192 EP - 198 PB - Fachhochschule Landshut CY - Landshut ER - TY - CHAP A1 - Roth, Carina A1 - Hausler, Peter A1 - Bierl, Rudolf T1 - Einbindung eines CMOS-Detektors in einen hochintegrierten SPR-Sensor T2 - 5. Landshuter Symposium Mikrosystemtechnik, März 2016 Y1 - 2016 SN - 78-3-9812696-9-7 SP - 200 EP - 205 PB - Fachhochschule Landshut CY - Landshut ER - TY - CHAP A1 - Lang, Christian A1 - Steinborn, Florian A1 - Steffens, Oliver A1 - Lang, Elmar Wolfgang ED - Valenzuela, O. ED - Rojas, F. ED - Herrera, L.J. ED - Pomares, H. ED - Rojas, I. T1 - Applying a 1D-CNN Network to Electricity Load Forecasting T2 - Theory and Applications of Time Series Analysis N2 - This paper presents a convolutional neural network (CNN) which can be used for forecasting electricity load profiles 36 hours into the future. In contrast to well established CNN architectures, the input data is one-dimensional. A parameter scanning of network parameters is conducted in order to gain information about the influence of the kernel size, number of filters and number of nodes. Furthermore, different dropout methods are applied to the CNN and are evaluated. The results show that a good forecast quality can already be achieved with basic CNN architectures, the dropout improves the forecast. The method works not only for smooth sum loads of many hundred consumers, but also for the load of single apartment buildings. KW - Energy load forecasting KW - STLF KW - Neural networks KW - CNN KW - Convolutional networks Y1 - 2020 U6 - https://doi.org/10.1007/978-3-030-56219-9_14 SP - 205 EP - 218 PB - Springer ER - TY - JOUR A1 - Reuther, Maike A1 - Steffens, Oliver T1 - Evaluation der Bauteiltemperierung für den Herzogskasten Abensberg JF - Bauphysik N2 - Die These, dass die Methode der direkten Temperierung von erdberührten oder anderweitig feuchtebelasteten Bauteilen zur Beseitigung von Feuchteschäden in Bestandsgebäuden auch die Energieeffizienz des Gebäudes erhöhen und sogar ohne weitere energetische Sanierungsmaßnahmen die Anforderungen der Energieeinsparverordnung (EnEV) erfüllen kann, wird anhand des als Museum genutzten Herzogskastens in Abensberg überprüft. In Verbindung mit einer Evaluation der Trocknungswirkung wird die Gebäude-Energieeffizienz durch Vergleich von Bedarfsberechnungen auf Basis der DIN V 18599 mit realen Verbrauchszahlen überprüft und diskutiert. KW - Bauteiltemperierung KW - energetische Sanierung KW - Gebäudeenergieeffizienz KW - Mauerwerkstrocknung KW - Denkmal KW - Restaurierung KW - DIN V 18599 KW - EnEV Y1 - 2015 U6 - https://doi.org/10.1002/bapi.201510010 VL - 37 IS - 2 SP - 96 EP - 99 PB - Ernst & Sohn, a Wiley Brand ER - TY - RPRT A1 - Schlamp, Matthias A1 - Ehrlich, Ingo ED - Baier, Wolfgang T1 - Analyse des Impact-Verhaltens gekrümmter Strukturbauteile von Luftfahrzeugen zur Entwicklung eines Strukturüberwachungssystems für faserverstärkte Kunststoffe - BIRD T2 - Forschung 2019 / Ostbayerische Technische Hochschule Regensburg N2 - Die in Flugvorausrichtung weisenden Bauteile von Luftfahrzeugen sind oftmals durch Einschläge aufgrund von Vogelschlag, Hagel oder aufgewirbelten Kleinteilen gefährdet. Diese Einschläge, sogenannte Impacts, weisen bei faserverstärkten Kunststoffen ein stark krümmungs- und materialabhängiges Verhalten und Schadensausmaß auf. Impact-Schädigungen führen oftmals zu hohen Reparaturkosten, welche durch eine genauere Kenntnis des Schadens verringert werden können. Zur Klassifizierung dieser Schädigungen steht dabei vor allem das auftretende Frequenz signal des Impacts im Fokus der Untersuchungen. Y1 - 2019 UR - https://doi.org/10.35096/othr/pub-789 SN - 978-3-9818209-6-6 SP - 40 EP - 41 PB - VMK Verlag für Marketing & Kommunikation GmbH & Co. KG ER - TY - JOUR A1 - Romano, Marco A1 - Micklitz, Matthias A1 - Olbrich, Florian A1 - Bierl, Rudolf A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Experimental investigation of damping properties of unidirectionally and fabric reinforced plastics by the free decay method JF - Journal of Achievements in Materials and Manufacturing Engineering N2 - 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. KW - structural vibration KW - damping KW - fibre reinforced plastics KW - mesomechanic scale KW - fabric reinforced layer Y1 - 2014 VL - 63 IS - 2 SP - 65 EP - 80 ER - TY - CHAP A1 - Jobst, Simon A1 - Bierl, Rudolf T1 - A Comparison of Correlation and Zero-Crossing Based Techniques in Ultrasonic Measurement T2 - 10th International Symposium on Applied Reconfigurable Computing (ARC'2014), Vilamoura, Algarve, Portugal, 14 - 16 April, 2014 N2 - 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. Y1 - 2014 ER - TY - CHAP A1 - Hofmann, Matthias A1 - Bierl, Rudolf A1 - Rück, Thomas T1 - Implementation of a dual-phase lock-in amplifier on a TMS320C5515 digital signal processor T2 - Proceedings of the 5th European DSP Education and Research Conference (EDERC), 13-14 Sept. 2012, Amsterdam N2 - 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. Y1 - 2012 U6 - https://doi.org/10.1109/EDERC.2012.6532217 ER - TY - CHAP A1 - Rück, Thomas A1 - Landgraf, Ferdinand A1 - Läpple, I. A1 - Unger, J. A1 - Matysik, Frank-Michael A1 - Bierl, Rudolf T1 - Specification of an improved photoacoustic setup for high-sensitive, low-cost NO2 trace gas detection T2 - 18th International Conference on Photoacoustic and Photothermal Phenomena (ICPPP18), 2015, September 6-10, Novi Sad, Serbia Y1 - 2015 ER - TY - CHAP A1 - van der Weerd, Bastiaan A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - A Conductivity Probe for the Determination of Carbon Dioxide Tension at the Oxygenator Exhaust Outlet during Extracorporeal Membrane Oxygenation (ECMO) T2 - analytica Conference 2014, 1. bis 4. April, München Y1 - 2014 ER - TY - CHAP A1 - van der Weerd, Bastiaan A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - A Conductivity Probe for the Determination of Carbon Dioxide Tension at the Oxygenator Exhaust Outlet during Extracorporeal Membrane Oxygenation (ECMO) T2 - Electrochemistry 2014, September 22 - 24, Mainz Y1 - 2014 ER - TY - CHAP A1 - van der Weerd, Bastiaan A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - A Planar Conductivity Probe for CO2 Determination at the Oxygenator Outlet T2 - Doktorandenseminar GDCh Prozessanalytik 2014, Berlin Y1 - 2014 ER - TY - CHAP A1 - Theuss, Horst A1 - Elian, Klaus A1 - Fink, Markus A1 - Fries, M. A1 - Kalz, Franz-Peter A1 - Schwabe, B. A1 - Vaupel, M. A1 - Jaroschek, C. A1 - Schubert, A. A1 - Hummel, H. A1 - Steffens, Oliver T1 - Mechanical Stress Impact of Assembly Processes onto a Stress-sensitive Testchip T2 - 44th International Symposium on Microelectronics (IMAPS 2011), October 9 - 13, 2011, Long Beach, California, USA N2 - 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. Y1 - 2011 SN - 978-1-61839-850-5 U6 - https://doi.org/10.4071/isom-2011-WA5-Paper3 IS - 1 SP - 619 EP - 626 PB - International Microelectronics & Packaging CY - Washington ER - TY - JOUR A1 - Malz, Sebastian A1 - Steininger, Peter A1 - Dawoud, Belal A1 - Krenkel, Walter A1 - Steffens, Oliver T1 - On the Development of a Building Insulation using Air Layers with Highly Reflective Interfaces JF - Energy and Buildings N2 - 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. KW - Building insulation KW - Infrared-reflective KW - Air layers KW - Energy-saving potential KW - Heat radiation Y1 - 2021 U6 - https://doi.org/10.1016/j.enbuild.2021.110779 IS - 236, April PB - Elsevier ER - TY - CHAP A1 - Steffens, Oliver A1 - Szabó, Peter A1 - Lenz, Michael A1 - Farkas, Gábor T1 - Thermal transient characterization methodology for single-chip and stacked structures BT - Best Paper Award T2 - Semiconductor Thermal Measurement and Management Symposium, 2005 N2 - 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. KW - Thermal resistance KW - Temperature KW - Electrical resistance measurement KW - Impedance KW - Assembly KW - Semiconductor device packaging KW - Surface resistance KW - Measurement techniques KW - MOSFETs Y1 - 2005 U6 - https://doi.org/10.1109/STHERM.2005.1412198 SN - 1065-2221 SP - 313 EP - 321 PB - IEEE ER - TY - JOUR A1 - Puff, Simone A1 - Seidel, Uwe M. A1 - Steffens, Oliver T1 - Pflege- und intensivmedizinische Bereiche im EnEV-Bewertungsverfahren JF - Bauphysik N2 - Die Anwendbarkeit des derzeit gültigen Verfahrens zur energetischen Bewertung von Nichtwohngebäuden gemäß aktueller Energieeinsparverordnung (EnEV 2014) in Verbindung mit DIN V 18599 als Planungs- und Bewertungstool auf Pflege- und intensiv-medizinische Bereiche von Krankenhäusern wird an einem beispielhaften, mittelgroßen Krankenhaus untersucht. Der Fokus liegt dabei auf der Praktikabilität der Abbildung von thermischen Lasten und Raumzuständen 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 für Maßnahmen zur Verbesserung der energetischen Performance und der Behaglichkeit in Krankenhäusern im Bereich der Planung erarbeitet. T2 - Energetic Evaluation of care and critical care units of hospitals according to EnEV 2014 KW - Energieeinsparungsverordnung KW - Krankenhaus Y1 - 2015 U6 - https://doi.org/10.1002/bapi.201510036 VL - 37 IS - 6 SP - 307 ER - TY - JOUR A1 - Wensauer, Andreas A1 - Steffens, Oliver A1 - Suhrke, Michael A1 - Rössler, Ulrich T1 - Laterally coupled few-electron quantum dots JF - Physical Review B N2 - 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. Y1 - 2000 U6 - https://doi.org/10.1103/PhysRevB.62.2605 VL - 62 IS - 4 SP - 2605 ER - TY - CHAP A1 - Steffens, Oliver ED - Trapp, Eugen T1 - "Grünes Denkmal" - Denkmalpflege und Erneuerbare Energien ergänzen sich T2 - Vorsicht Baudenkmal! Konfliktfelder Umwelt - Nutzung - Geschichte. Beiträge des 28. Regensburger Herbstsymposions für Kunst, Geschichte und Denkmalpflege vom 22. bis 24. November 2013 KW - Denkmalpflege KW - Denkmalschutz KW - Erneuerbare Energien Y1 - 2014 SN - 978-3-937527-77-2 SP - 9 EP - 17 PB - Regensburg CY - Morsbach-Verl. ER - TY - CHAP A1 - Steffens, Oliver A1 - Suhrke, Michael A1 - Rössler, Ulrich ED - Gershoni, David T1 - Correlation in few-electron quantum dots: Spin effects and spontaneous currents T2 - 24rd International Conference on the Physics of Semiconductors (ICPS 24), Jerusalem, Israel, August 2-7, 1998 Y1 - 1999 SN - 978-981-02-3613-7 PB - World Scientific CY - Singapore ER - TY - THES A1 - Gering, Stefan T1 - Thermische Detailsimulationen in der Bestandssanierung Y1 - 2014 CY - Regensburg ER - TY - JOUR A1 - Szabó, Peter A1 - Steffens, Oliver A1 - Lenz, Michael A1 - Farkas, Gábor T1 - Transient junction-to-case thermal resistance measurement methodology of high accuracy and high repeatability JF - IEEE Transactions on Components and Packaging Technologies N2 - 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. KW - Thermal resistance KW - Electrical resistance measurement KW - Temperature KW - Packaging KW - Cold plates KW - MOSFET circuits KW - Semiconductor device measurement KW - Surface resistance KW - Microassembly KW - Thermal conductivity Y1 - 2005 U6 - https://doi.org/10.1109/TCAPT.2005.859768 SN - 1521-3331 VL - 28 IS - 4 SP - 630 EP - 636 ER - TY - JOUR A1 - Mayrock, Oliver A1 - Mikhailov, Sergej A. A1 - Steffens, Oliver A1 - Rössler, Ulrich T1 - Observability of the acoustic plasma mode in double-layered quantum dots JF - Physica E: Low-dimensional Systems and Nanostructures N2 - 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. KW - Quantum dots KW - Collective excitations KW - Magneto-plasmon KW - Acoustic modes Y1 - 1997 U6 - https://doi.org/10.1016/S1386-9477(97)00048-9 VL - 1 IS - 1-4 SP - 232 EP - 234 ER - TY - GEN A1 - Köhler, Ann-Kathrin A1 - Ostermeier, Nadine A1 - Schaubächer, Ursula A1 - Wolf, Lars T1 - Einfluss der Wärmespeicherfähigkeit von Massivbauteilen auf den Heizwärmebedarf und die Behaglichkeit eines Gebäudes BT - Literaturstudie. Masterprojektarbeit KW - Wärmespeicherung KW - Massivbau KW - Energieeinsparung KW - Behaglichkeit KW - Gebäude Y1 - 2015 CY - Regensburg ER - TY - RPRT A1 - Schaubeck, Simon A1 - Steffens, Oliver A1 - Rechenauer, Christian T1 - Integration eines kostenoptimierten, wirtschaftlich rentablen Blockheizkraftwerks mit mittlerer thermischer Leistung in ein genossenschaftliches Wohnquartier BT - TWO-Projekt (Technologie- und Wissenschaftsnetzwerk Oberpfalz), Endbericht 08 / 2015 Y1 - 2015 ER - TY - CHAP A1 - Rechenauer, Christian A1 - Neuleitner, Nikolaus A1 - Steffens, Oliver T1 - Empirische Untersuchung und Optimierung der Performance eines Modellprojekts für ein Effizienzhaus Plus mit solarthermischem Energiekonzept T2 - Fachforum Effizienzhaus Plus, 14.07.2015 Y1 - 2015 CY - Hamburg ER - TY - BOOK A1 - Steffens, Oliver T1 - Einfluss der Potentialmodulation auf Magnetotransport und Quantenchaos in lateralen Halbleiter-Übergittern Y1 - 1996 SN - 978-3-89608-726-3 N1 - Mikrofiche-Ausg. PB - Tectum-Verl. CY - Marburg ER - TY - RPRT A1 - Steffens, Oliver T1 - Saisonale Wärmespeicherung von opaken Bauteilen im Massivbau BT - Literatur-Übersicht Y1 - 2015 ER - TY - JOUR A1 - Raith, Lea A1 - Schmidling, Anja A1 - Windisch, Bastian T1 - Bauteiltemperierung BT - Studienarbeit Y1 - 2012 CY - Regensburg ER - TY - JOUR A1 - Steffens, Oliver A1 - Suhrke, Michael A1 - Rotter, Peter A1 - Rössler, Ulrich T1 - From Landau levels to universal fluctuations: Level statistics for lateral superlattices JF - Physical Review B N2 - 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. Y1 - 1997 U6 - https://doi.org/10.1103/PhysRevB.55.4486 VL - 55 IS - 7 SP - 4486 EP - 4493 ER - TY - JOUR A1 - Steffens, Oliver A1 - Wensauer, Andreas A1 - Suhrke, Michael T1 - Collective excitations in quantum dots: Calculated Raman spectra JF - physica status solidi (b) N2 - 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. Y1 - 1999 U6 - https://doi.org/10.1002/(SICI)1521-3951(199909)215:1<365::AID-PSSB365>3.0.CO;2-C VL - 215 SP - 365 EP - 371 PB - Wiley ER - TY - JOUR A1 - Suhrke, Michael A1 - Steffens, Oliver A1 - Rotter, Peter A1 - Rössler, Ulrich T1 - Quantum chaos and magnetotransport in lateral superlattices: The transition from weak to strong modulation potential JF - Physica E: Low-dimensional Systems and Nanostructures N2 - 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. KW - Lateral superlattices KW - Quantum chaos KW - Level statistics KW - Magnetotransport KW - Commensurability oscillations Y1 - 1997 U6 - https://doi.org/10.1016/S1386-9477(97)00060-X SN - 1386-9477 VL - 1 IS - 1-4 SP - 281 EP - 287 ER - TY - RPRT A1 - Steffens, Oliver A1 - Rössler, Ulrich A1 - Suhrke, Michael T1 - Comment on "Shell Filling and Spin Effects in a Few Electron Quantum Dot" T2 - Physical Review Letters N2 - 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. Y1 - 1996 UR - http://arxiv.org/abs/cond-mat/9711077 VL - 77 SP - 3613 ER - TY - JOUR A1 - Steffens, Oliver T1 - Energetische Modernisierung und Restaurierung historisch wertvoller Stadtquartiere. Regenerative Energieversorgung als Schwerpunkt einer nachhaltigen Modernisierung historisch wertvoller Stadtquartiere (RENARHIS) JF - Zukunft bauen. Forschungsinitiative Zukunft Bau 2016 Y1 - 2016 IS - 5 SP - 62 EP - 65 PB - Bundesministerium für Umwelt, Naturschutz, Bau und Reaktorsicherheit (BMUB) ER - TY - GEN A1 - Steffens, Oliver A1 - Saller, Tobias T1 - Modernisierungskonzepte für das denkmalgeschützte Ensemble am Jahn-Stadion Regensburg Prüfeninger Straße 47–52 BT - Studiengang Gebäudeklimatik. Studienarbeiten Y1 - 2014 ER - TY - RPRT ED - Neuleitner, Nikolaus ED - Steffens, Oliver T1 - Energienutzungsplan für die Gemeinde Sinzing BT - Phase I. Bestandsaufnahme. Ergebnisbericht 1 (12/2011) Y1 - 2011 ER - TY - CHAP A1 - Gerhards, Helene ED - Mauer, Heike ED - Leinius, Johanna ED - Gerhards, Helene T1 - Von Patient*innenzellen und Patient*innenzahlen BT - Intersektionale Perspektiven auf biomedizinische Forschung T2 - Intersektionalität und Postkolonialität ; kritische feministische Perspektiven auf Politik und Macht Y1 - 2021 SN - 9783847424550 U6 - https://doi.org/10.3224/84742455 SP - 181 EP - 203 PB - Verlag Barbara Budrich CY - Opladen; Berlin ER - TY - JOUR A1 - Hartmann, Julia A1 - Heckner, Markus A1 - Plach, Ulrike T1 - Future Skills bei Studierenden – Messung und Einflussfaktoren JF - Die Neue Hochschule N2 - Eine sich stetig verändernde Arbeitswelt erfordert neue Kompetenzen von unseren Studierenden. In der Lehre gilt es nicht nur, diese Zukunftskompetenzen (sog. Future Skills) zu fördern, sondern diese auch zu messem und sichtbar zu machen. KW - Future Skills KW - Studierende Y1 - 2023 UR - https://www.yumpu.com/de/document/read/68553002/die-neue-hochschule-heft-6-2023 IS - 6 SP - 24 EP - 27 ER -