TY - CHAP A1 - Ławrowski, Robert Damian A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Schreiner, Rupert T1 - Field emission from three-dimensional epitaxial grown GaN-microrods T2 - 29th International Vacuum Nanoelectronics Conference (IVNC), 2016, 11-15 July, Vancouver, BC, Canada N2 - A novel three-dimensional epitaxial technique allows on patterned substrates the realization of gallium nitride pillars, also known as nano- and microrods. The typical dimensions of the microrods are in the range of one micron for the radius of the hexagonal footprint and about 10 μm in height. The microrods consist of a semiconductor heterostructure with an n GaN core, a n-GaN shell, a p GaN shell and an intermediate quantum well layer. The field emission properties were investigated in diode configuration by integral field emission measurements in a vacuum chamber at pressures around 10 -9 mbar. The spacer was mica with a thickness of 50 μm. A metallized fine-meshed nitride grid (or a metallized Si-grid) was used as anode. A current of about 1 μA at a voltage of 1250 V (1750 V) was measured. An onset field of about 12.5 MV/m (20 MV/m) and field enhancement factors in the range of 200 to 500 (150 to 300) were found. The investigation with the fine-meshed grid showed an expected pronounced saturation region. KW - field emission KW - GaN KW - LED Y1 - 2016 U6 - https://doi.org/10.1109/IVNC.2016.7551477 SN - 2380-6311 SP - 87 EP - 88 PB - IEEE ER - TY - CHAP A1 - Prommesberger, Christian A1 - Ławrowski, Robert Damian A1 - Langer, Christoph A1 - Mecani, Mirgen A1 - Huang, Yifeng A1 - She, Juncong A1 - Schreiner, Rupert ED - Tiginyanu (Ed.), Ion M. T1 - Field emission properties of ring-shaped Si ridges with DLC coating T2 - Proc. SPIE 10248, Nanotechnology VIII, 102480H (30 May 2017) N2 - We report on the fabrication and the emission characterization of single ring-shaped Si ridges with a coating of diamond-like carbon (DLC). The reactive ion etching and the subsequent inductively coupled plasma step were adjusted to realize ring-shaped Si ridges with a height of 7.5 μm respectively 15 μm and an apex radius of 20 – 25 nm. The samples were coated with a DLC layer (thickness ≈ 2 – 5 nm) by a filtered cathodic vacuum arc deposition system in order to lower the work function of the emitter and to improve the field emission characteristics. The field emission characterizations were done in diode configuration with cathode and anode separated by a 50 μm thick mica spacer. A higher emission current was carried out for the ring-shaped Si ridge in comparison to the point-shaped Si tips due to the increased emission area. The highest emission current of 0.22 μA at 1000 V was measured on a DLC-coated sample with the highest aspect ratio. No degradation of the emission current was observed in the plateau regime during a measurement period of 6 h. Finally, no decreasing performance of the field emission properties was found due to changes in the geometry or destructions. KW - Etching KW - Scanning electron microscopy KW - Silicon carbide KW - Carbon KW - Mica KW - Oxides Y1 - 2017 U6 - https://doi.org/10.1117/12.2265627 VL - 102480H PB - Society of Photo-Optical Instrumentation Engineers (SPIE) ER - TY - CHAP A1 - Thumann, Philipp A1 - Wagner, Marcus A1 - Suck, Bertram A1 - Meinhardt, Josef A1 - Marburg, Steffen T1 - Explicit and Implicit FE Simulations of Material Tests for Subsequent Durability Analyses T2 - 11th European LS-DYNA Conference, Salzburg N2 - Because of increased stroke rates the loads on forming tools increase too. To ensure a save design of components, durability analyses are intended. For this, simulation results from FE analyses are necessary. Therefore, it is desirable to use elements with quadratic function, because of a good stress approximation.The goal of the described investigation is to show if calculation results created by LS-DYNA [1] can be used for durability analyses. Especially the use of quadratic elements is investigated. For the evaluation, on the one hand explicit FE analyses of a special durability test are carried out. These analyses are validated by available test data. To create results for later durability analyses further FE analyses with implicit time discretisation are carried out. In this paper results of the investigations are presented and evaluated critically. Y1 - 2017 UR - https://www.dynalook.com/conferences/11th-european-ls-dyna-conference/experiments-and-parameter-optimization/explicit-and-implicit-fe-simulations-of-material-tests-for-subsequent-durability-analyses ER - TY - CHAP A1 - Thumann, Philipp A1 - Swidergal, Krzysztof A1 - Wagner, Marcus T1 - Calculation and validation of material tests with specimens made out of filled elastomers T2 - 10th European LS-DYNA Conference 2015, Würzburg N2 - In deep-drawing dies for steel sheet parts of car bodies huge masses are moved. To prevent vibrations, which occur by sudden acceleration or stopping of those masses, elastomeric tubular dampers [1] are used. The dampers are made out of carbon filled elastomers. A good knowledge about the material behaviour of metals is available. But for the numerical investigation of complete deep-drawing dies the elastomeric dampers must be taken into account, too. To characterize the material behaviour of the elastomers tensile tests and pressure tests were carried out. The received material data from the tests were read into LS-DYNA [2]. Simulation models of the tensile test and the pressure test were created for LS-DYNA according to the real dimensions and boundary conditions. For validation purposes, calculations of loading cycles were done to enable a comparison between test data and simulation results. For the calculations the implemented material model *MAT_SIMPLIFIED_RUBBER_WITH_DAMAGE (*MAT_183) was used. The comparison shows a good fitting between the test data and the calculation results with respect to the mechanical material behaviour by using this material model in single loading cases. The settings from the simulations of material tests were transferred to simulations of dampers, which are used in deep-drawing dies. Y1 - 2015 UR - https://www.semanticscholar.org/paper/Calculation-and-validation-of-material-tests-with-Thumann-Swidergal/7502f1c70a07654c8238f4a6bd436aa5bd4c051f ER - TY - CHAP A1 - Koch, F. A1 - Thumann, Philipp A1 - Wagner, Marcus T1 - Simulation with implicit time integration of high loaded areas of a forming tool for large presses using LS-DYNA T2 - 13. LS-DYNA Forum 2014, 6.-8. Oktober, Bamberg Y1 - 2016 ER - TY - CHAP A1 - Meckl, D. A1 - Lubeseder, Christian A1 - Zausinger, C. A1 - Wurmb, Ingo von A1 - Meinhardt, Josef A1 - Swidergal, Krzysztof A1 - Wagner, Marcus T1 - Simulation of press dies for large presses using the flexible multibody dynamics in Recurdyn T2 - 4th RecurDyn TechnologyDays 2014, München Y1 - 2014 ER - TY - CHAP A1 - Bachmann, Michael A1 - Dams, Florian A1 - Düsberg, Felix A1 - Hofmann, Martin A1 - Pahlke, Andreas A1 - Langer, Christoph A1 - Ławrowski, Robert Damian A1 - Prommesberger, Christian A1 - Schreiner, Rupert T1 - Control of the electron source current T2 - International Vacuum Nanoelectronics Conference (IVNC), 30th, 2017, Regensburg N2 - A control circuit to stabilize the flux of electrons transmitted through an extractor electrode is presented. By controlling the emission current a fluctuation with a standard deviation of 0.015% is observed. However, the achievable stability of the transmitted electron current is limited due to a variation of the extraction grid current ratio showing a standard deviation of 4.33%. By regulating the difference of the emission current and the extraction grid current an improved stability of the transmitted electron current down to a standard deviation of 0.280% is observed. Even with operation at 2 × 10 -5 mbar a standard deviation of 0.558% is achieved. KW - Standards KW - Circuit stability KW - Power system stability KW - Current measurement KW - Voltage measurement KW - Electron sources KW - Stability analysis Y1 - 2017 U6 - https://doi.org/10.1109/IVNC.2017.8051550 SP - 66 EP - 67 PB - IEEE ER - TY - CHAP A1 - Prommesberger, Christian A1 - Langer, Christoph A1 - Ławrowski, Robert Damian A1 - Schreiner, Rupert T1 - Benzocyclobutene as a novel integrated spacer material in a field emission electron source T2 - International Vacuum Nanoelectronics Conference (IVNC), 30th, 2017, Regensburg N2 - For the realization of a miniaturized field emission electron source we tested benzocyclobutene (BCB) as a new spacer material between cathode and anode. We fabricated black silicon emitters and characterized the emission behavior with an integrated 5 μm thin and large-area spacer of BCB. The integrated BCB layer allows the realization of a compact electron source with only two components consisting of a cathode with BCB and a grid. The comparison with other spacer materials like polyimide (25 μm thickness) or mica (50 μm thickness) revealed for the cathode with BCB a significantly reduced operational voltage of 240 V for a field emission current of 1 μA. KW - field emission KW - benzocyclobutene KW - integrated spacer KW - electron source KW - black silicon Y1 - 2017 U6 - https://doi.org/10.1109/IVNC.2017.8051605 SP - 192 EP - 193 PB - IEEE ER - TY - CHAP A1 - Swidergal, Krzysztof A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Meinhardt, Josef A1 - Wagner, Marcus A1 - Marburg, Steffen T1 - Effiziente Methode zur Bestimmung von dynamischen strukturellen Belastungen in Großpresswerkzeugen T2 - 36. EFB-Kolloquium Blechverarbeitung 2016, Fellbach Y1 - 2016 ER - TY - RPRT A1 - Thumann, Philipp A1 - Swidergal, Krzysztof A1 - Wagner, Marcus ED - Baier, Wolfgang T1 - Experimentelle Ermittlung von Materialkennwerten und numerische Untersuchungen an einem gefüllten Elastomer T2 - Forschungsbericht 2015 / Ostbayerische Technische Hochschule Regensburg Y1 - 2015 UR - https://doi.org/10.35096/othr/pub-1386 SN - 978-3-00-048589-3 SP - 49 EP - 50 ER - TY - JOUR A1 - Swidergal, Krzysztof A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Lipp, Arnulf A1 - Meinhardt, Josef A1 - Wagner, Marcus A1 - Marburg, Steffen T1 - Experimental and numerical investigation of blankholder’s vibration in a forming tool BT - a coupled MBS-FEM approach JF - Production Engineering - Research and Development N2 - In order to achieve the energy and efficiency goals in modern automotive press shops, press systems with increasingly high stroke rates are being implemented (Meinhardt in proceedings of ACI forming in car body engineering. Bad Nauheim, Germany 2012). As a side effect, the structural dynamic loads on the press and especially on the forming tool increase. Hence, to design reliable and withstanding forming tools, a detailed knowledge of the vibrations and resulting critical loads is essential. In this paper, the main focus is put on the vibration of the blankholder—the heaviest moving component in the forming tool. To predict those vibrations, a coupled multibody-finite element simulation (MBS-FEM) is conducted, which combines rigid and elastic modeling approaches. Also, an experimental validation of the blankholder vibration under operational load is carried out. To compare the numerical and experimental results—both in time and frequency domain—an 1/3-octave analysis of a blankholder’s vibrational speed is performed. The test measurements agree well with the MBS-FEM simulation. KW - Forming tool/die KW - Coupled MBS-FEM simulation KW - Blankholder KW - Vibration KW - Servo press Y1 - 2015 U6 - https://doi.org/10.1007/s11740-015-0640-9 SN - 0944-6524 VL - 9 IS - 5-6 SP - 634 PB - Springer ER - TY - JOUR A1 - Thumann, Philipp A1 - Marburg, Steffen A1 - Meinhardt, Josef A1 - Saubiez, Jean‐Marc A1 - Hoogen, Michael A1 - Suck, Bertram A1 - Wagner, Marcus T1 - Frequency Dependent Fatigue Strength Investigations on Tempered Steel and Nodular Cast Iron JF - steel research international N2 - This paper presents experimental fatigue tests on specially shaped specimens made from quenched and tempered steel 42CrMoS4 and nodular cast iron EN-GJS-600-3. The specimens are geometrically designed to resemble actual subcomponents of forming and cutting dies for sheet metal manufacturing. These subcomponents have failed in the past.Experiments are carried out using a fictive load-time function, which is a modification of an actually measured load curve and has variable mean and amplitude values. This first test series serves as a general validation of a subsequent fatigue analysis. A second test series is carried out with constant mean and amplitude values with a load ratio 𝑅≈0. Here, the load frequencies in the individual test runs are varied between f = 5 Hz and f = 45 Hz in order to investigate the influence of the frequency. Both series are performed on a servo-hydraulic testing machine.The experimental data is then statistically evaluated. The values for the scatter correlate with data from the literature. The data from the test series with the fictive load-time function can thus be used for subsequent validation of a fatigue calculation, which will be addressed in a future publication. Most significant are the findings from the second series of experiments with varied load frequencies, as a significant frequency influence could be detected. Furthermore, the hardening and softening behavior under cyclic loading and the fracture behavior of the materials are analyzed and compared with data from the literature. KW - cast iron KW - fatigue analysis KW - fatigue strength KW - frequency dependence KW - materials testing KW - tempering steel Y1 - 2019 U6 - https://doi.org/10.1002/srin.201800620 VL - 90 IS - 7 PB - Wiley ER - TY - CHAP A1 - Swidergal, Krzysztof A1 - Wagner, Marcus A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Meinhardt, Josef A1 - Marburg, Steffen T1 - Finite element simulation of blankholder’s lift-off in a deep drawing tool using Abaqus/Standard T2 - SIMULIA Community Conference, 19 - 21 May 2015, Berlin, Germany N2 - In the deep drawing tools for forming car body parts, heavy blankholders are used to prevent buckling and wrinkling of the blank. During each press cycle, those large masses need to be lifted, raising thereby the structural dynamic load on the deep drawing tool and on the press. Therefore a detailed knowledge about the blankholder’s lift-off event is essential for an accurate and robust design of forming tools. In this paper, a dynamic finite element method (FEM) simulation of a blankholder’s lift-off in a selected automotive deep drawing tool is presented enabling identification of regions of critical stresses. The FEM model is built within the Abaqus/CAE environment and solved with Abaqus/Standard. Each dynamic analysis is preceded by a static analysis where the gravity load is applied and the lifting bolts are pre-stressed. A special emphasis is put on modeling the elastomer dampers, which are installed between lifting bolts and the blankholder to avoid hard impacts during the lift-off event. Those dampers are modelled using a hyperelastic material with hysteresis. In addition, an experimental validation of a blankholder’s vibration under operating loading was carried out. The simulation results are in good agreement with the measurements. Y1 - 2015 UR - https://www.semanticscholar.org/paper/Final-Element-Simulation-of-Blankholder-'-s-in-a-%2F-Swidergal-Wagner/8398357757311fc364e3b942cc92c8c0a5f216bc ER - TY - JOUR A1 - Sittl, Christopher A1 - Marburg, Steffen A1 - Wagner, Marcus T1 - Application of a Krylov subspace method for an efficient solution of acoustic transfer functions JF - Mechanical Systems and Signal Processing N2 - Solving acoustic radiation problems, arising from systems including fluid–structure interaction, is of interest in many engineering applications. Computing frequency response functions over a large frequency range is a concern in such applications. A method which solves the Helmholtz equation for multiple frequencies in one step is the matrix-Padé-via-Lanczos connection for unsymmetric systems, as presented by Wagner et al. [1]. The present work is based on Ref. [1] and presents a method for efficiently computing frequency responses over a frequency range for coupled structural-acoustic problems, where the structure and the acoustic near field are discretized with finite elements and an analytical Dirichlet-to-Neumann map approximates the far field. The method is based on a Krylov-subspace projection technique which derives a matrix-valued Padé approximation for a restricted area in the near field and the pressure field on a spherical boundary. On the spherical boundary, where the finite domain is truncated, the non-local modified Dirichlet-to-Neumann operator is applied as a low-rank update matrix. The present contribution extends this method and incorporates new techniques for a more stable model reduction through the Lanczos algorithm and a novel weighted adaptive windowing technique. Further, structural damping is incorporated, for computing the acoustic radiation of a harmonically excited plate. These computed results are compared with acoustic measurements in an anechoic chamber and verified with computational results obtained with a commercial code that uses the perfectly matched layer method. KW - Lanczos algorithm KW - Krylov-subspace projection KW - Dirichlet-to-Neumann map KW - Padé approximation KW - Fluid–structure interaction KW - Acoustics Y1 - 2021 U6 - https://doi.org/10.1016/j.ymssp.2020.107135 VL - 148 PB - Elsevier ER - TY - CHAP A1 - Swidergal, Krzysztof A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Meinhardt, Josef A1 - Wagner, Marcus A1 - Marburg, Steffen T1 - Vibration analysis of an automotive forming tool using coupled MBS-FEM simulation and experimental validation T2 - Proceedings of the 26th International Conference on Noise and Vibration Engineering (ISMA2014), Leuven, Belgium N2 - To improve efficiency in automotive press shops, press systems with increasingly high stroke rates are beingimplemented, raising thereby the structural dynamic load on the press and especially on the forming tool. Adetailed knowledge of the vibrations and resulting critical loads is thus essential for accurate and reliable de-signs of forming tools. In this paper, multibody simulation (MBS) of a selected automotive tool is presentedenabling the identification of the vibration of its components. Starting from a pure rigid modelling approach,the MBS model is extended by adding finite element (FE) component to allow extra flexibility in the sys-tem. As an example, a detailed vibrational analysis - both in time and frequency domain - is performed ona blankholder. Also an experimental validation of a blankholder vibration under operational load is carriedout, with test signal data gained by piezoelectric accelerometers. Y1 - 2014 UR - http://past.isma-isaac.be/downloads/isma2014/papers/isma2014_0245.pdf SP - 2931 EP - 2942 ER - TY - CHAP A1 - Ławrowski, Robert Damian A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Schreiner, Rupert T1 - Microrods and microlines by three-dimensional epitaxially grown GaN for field emission cathodes T2 - International Vacuum Nanoelectronics Conference (IVNC), 30th, 2017, Regensburg N2 - The three-dimensional epitaxial technique allows the realization of gallium nitride lines in addition to the rods. To optimize the properties of GaN-based field emission cathodes further investigations and an improvement of the epitaxial process were performed. The microrods and microlines consist of a one-order higher n-doped gallium nitride in comparison to the gallium nitride layer on the sapphire substrate. The typical height of the microrods and -lines is about 5 μm. The field emission properties of these structures were investigated in diode configuration by integral field emission measurements at pressures below 10 -9 mbar. For the microrods (microlines) a voltage of 1100 V (2000 V) was measured for a field emission current of about 0.5 μA with an onset field of about 12 MV/m (24 MV/m). Furthermore, the field enhancement factors for microrods and -lines are in the range of 300 and 200, respectively. KW - field emission KW - GaN KW - LED KW - Gallium nitride KW - Epitaxial growth Y1 - 2017 U6 - https://doi.org/10.1109/IVNC.2017.8051576 SP - 130 EP - 131 PB - IEEE ER - TY - CHAP A1 - Ławrowski, Robert Damian A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Schreiner, Rupert T1 - Light emitting diodes based on three-dimensional epitaxial grown crystalline GaN rods T2 - 7. MikroSystemTechnik Kongress "MEMS, Mikroelektronik, Systeme", 23.-25. Oktober 2017, München Y1 - 2017 SN - 978-3-8007-4491-6 SP - 131 EP - 134 PB - VDE-Verlag CY - München ER - TY - CHAP A1 - Serbun, Pavel A1 - Porshyn, Vitali A1 - Müller, Günter A1 - Lützenkirchen-Hecht, Dirk A1 - Prommesberger, Christian A1 - Langer, Christoph A1 - Ławrowski, Robert Damian A1 - Schreiner, Rupert T1 - Field emission behavior of single n- and p-type black Si pillar structures T2 - International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan N2 - We have investigated the properties of single n- and p-type black silicon (b-Si) pillars with a height of 20 μ m under strong electric field and halogen lamp or laser illumination. For both type of b-Si pillar structures, I-V measurements revealed strong activation effects, which consisted in sudden current increases during the first up/down voltage sweeps. The maximum reproducible emission current from a single n-type b-Si pillar structure was about 15 μ A. A pronounced saturation region at 240 nA was observed for a single p-type b-Si pillar. The current fluctuation over time showed a standard deviation of 28% and 2.5% for n- and p-type single b-Si pillar structures, respectively. Optical switching under halogen lamp illumination resulted in at least 3 times higher saturation currents and showed a linear dependence of the FE current on the laser power. KW - field emission KW - black silicon KW - photoemission Y1 - 2018 U6 - https://doi.org/10.1109/IVNC.2018.8520292 PB - IEEE 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 - Ławrowski, Robert Damian A1 - Langer, Christoph A1 - Schreiner, Rupert A1 - Sellmair, Josef T1 - Nano Emitters on Silicon Pillar Structures generated by a Focused Electron Beam Induced Deposition T2 - International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan N2 - Nano emitters were deposited by focused electron beam induced deposition of Trimethyl-(methylcyclopentadienyl)platinum(IV) on top of silicon pillars. The nano emitters were exactly positioned in the center on the top of up to four pillars of a quadratic arranged array of sixteen pillars with a pitch of 50 μm. Integral field emission measurements were performed in a diode configuration with a 50 μm mica spacer in a vacuum chamber at pressures of about 10 -9 mbar. The Fowler-Nordheim plots show a linear behavior, like expected for an n-type silicon material and a metal needle. The I-V measurement of the most promising sample shows an integral emission current up to 2 μm at a voltage of 600 V (12 MV/m) and an onset voltage for a current of 1 nA of about 300 V. KW - field emission KW - nano emitter KW - focused electron beam induced deposition KW - MeCpPtMe3 Y1 - 2018 U6 - https://doi.org/10.1109/IVNC.2018.8520059 PB - IEEE 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 - CHAP A1 - Langer, Christoph A1 - Hausladen, Matthias A1 - Prommesberger, Christian A1 - Ławrowski, Robert Damian A1 - Bachmann, Michael A1 - Düsberg, Felix A1 - Pahlke, Andreas A1 - Shamonin (Chamonine), Mikhail A1 - Schreiner, Rupert T1 - Field emission current investigation of p-type and metallized silicon emitters in the frequency domain T2 - International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan N2 - We investigated two different field emitter arrays consisting of 10×10 p-type and 10×10 undoped Au-coated high aspect ratio silicon tips. The I-V characterization of the p-type sample showed a pronounced saturation for voltages higher than 500 V and a maximum emission current of 39 nA. The metallized sample revealed a FN-like emission up to several μA. The metallized and the p-type sample operating below the saturation region showed high current fluctuations of ±16%. Whereas, the metallized sample with current regulation and the p-type sample in the saturation yielded a current stability of ±0.4% and ±0.3%, respectively. Investigations in the frequency domain revealed the for field emission typical 1/f-noise. By operating in the saturation region (p-type sample) or using an emission current regulation (metallized sample) the noise level was reduced by at least 20 dB. Finally, the p-type sample was illuminated by a light emitting diode to increase and modulate the emission current in the saturation region. The emission current was increased by a factor of 3.7 to 145 nA. With this configuration we emulated an unstable emission behavior and evaluated the performance of our emission current regulation circuit. KW - field emission KW - field emitter array KW - silicon tip KW - current fluctuation KW - current stability KW - field emission noise Y1 - 2018 U6 - https://doi.org/10.1109/IVNC.2018.8520127 PB - IEEE ER - TY - CHAP A1 - Serbun, Pavel A1 - Porshyn, Vitali A1 - Lützenkirchen-Hecht, Dirk A1 - Prommesberger, Christian A1 - Langer, Christoph A1 - Ławrowski, Robert Damian A1 - Schreiner, Rupert T1 - Photosensitivity of single silicon high-aspect-ratio tips with different doping levels T2 - International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan N2 - Photosensitivity of single lightly p-doped, highly p-doped, with an integrated p/n junction and intrinsic high-aspect-ratio (HAR) silicon tips was investigated in an ultra-high vacuum environment. The current-voltage characteristics (I-V) of the lightly doped p-type HAR tips showed a characteristic current saturation at around 10-12 nA, whereas the HAR Si tips with p/n junction showed similar saturation phenomena, however, at much smaller current values starting at ~20-30 pA. Optical switching under a halogen lamp illumination resulted in at least 2-4 times higher saturation currents and showed a linear dependence between the illumination power and the FE current, for both types of structures. In case of the highly p-doped HAR tips optical current switching effects, i. e. current saturation, were observed at rather low current levels 1-2 pA. Intrinsic HAR Si-tips showed relative unstable field emission behavior without a clear evidence of the photosensitivity. KW - field emission KW - Si p/n junction KW - p-type Si KW - photosensitivity Y1 - 2018 U6 - https://doi.org/10.1109/IVNC.2018.8520288 PB - IEEE ER - TY - PAT A1 - Schubert, Martin J. W. T1 - Verfahren zur Simulation von Netzwerken auf einer ereignisgesteuerten Zeitachse mittels verteilter, lokaler Iteration Y1 - 1996 ER - TY - PAT A1 - Declerq, Michel A1 - Schubert, Martin J. W. T1 - Circuit Intermédiaire entre un Circuit Logique à Basse-Tension et un Etage de Sortie à Haute-Tension Réalisés dans une Technologie CMOS Standard N2 - La présente invention concerne un circuit intermédiaire entre un circuit logique a basse tension et un étage de sortie à haute tension réalisés dans une technologie CMOS standard. L'étage de sortie (20) comporte deux transistors respectivement à canal N et à canal P, réalisés selon une technologie CMOS standard. Le circuit intermédiaire comporte un translateur de niveau de tension (21) couplé entre un circuit logique d'entrée SL et ledit étage de sortie (20). Ce translateur de niveau de tension (21) est réalisé selon une technologie CMOS standard et est constitué d'au moins deux blocs de base identiques formant des miroirs de tension interconnectés de façon croisée. Ce circuit est utilisé pour commander des transducteurs, des écrans plasma et des actionneurs électromécaniques. Y1 - 1992 ER - TY - RPRT A1 - Hederer, Sebastian A1 - Wagner, Marcus ED - Baier, Wolfgang T1 - Entwicklung und Implementierung eines konstitutiven Modells zur Beschreibung der Plastizität von Dualphasenstähle bei großen plastischen Deformationen T2 - Forschungsbericht 2018 / Ostbayerische Technische Hochschule Regensburg Y1 - 2018 UR - https://doi.org/10.35096/othr/pub-1382 SN - 9783981820911 SP - 68 EP - 69 ER - TY - CHAP A1 - Swidergal, Krzysztof A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Lipp, Arnulf A1 - Meinhardt, Josef A1 - Wagner, Marcus A1 - Marburg, Steffen T1 - Structural analysis of an automotive forming tool for large presses using LS-DYNA T2 - 10th European LS-DYNA Conference, Würzburg Y1 - 2015 ER - TY - CHAP A1 - Wegh, Niels A1 - Wagner, Marcus A1 - Gaudlitz, Daniel A1 - Finckh, Hermann A1 - Klein, Markus T1 - Numerical Simulation of Filling Process in Resin Transfer Molding T2 - 13th International Conference on Flow Processes in Composites Materials (FPCM-13), Kyoto, Japan Y1 - 2016 UR - https://www.fose1.plymouth.ac.uk/sme/fpcm/fpcm13/Abstracts/FPCM-13_extended_abstract_21.pdf ER - TY - CHAP A1 - Geith, Markus A. A1 - Wagner, Marcus T1 - Numerical Analysis Of Stent Delivery Systems During Pre- And Intraoperative Processes T2 - Deutsches LS-DYNA Forum 2018, Bamberg Y1 - 2018 ER - TY - CHAP A1 - Swidergal, Krzysztof A1 - Thumann, Philipp A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Meinhardt, Josef A1 - Wagner, Marcus A1 - Marburg, Steffen T1 - Modeling and simulation of carbon black filled elastomer damper using LS-DYNA T2 - LS-DYNA Forum 2014, Bamberg Y1 - 2014 ER - TY - JOUR A1 - Ledentsov, Dmitry A1 - Düster, Alexander A1 - Volk, Wolfram A1 - Wagner, Marcus A1 - Heinle, Ingo A1 - Rank, Ernst T1 - Model adaptivity for industrial application of sheet metal forming simulation JF - Finite Elements in Analysis and Design N2 - finite element simulation of sheet metal forming, shell elements are widely used. The limits of applicability of the shell elements are sometimes disregarded, which leads to an error in predictions of important values such as springback geometry. The underlying kinematic assumptions of the shell elements do not hold where the thickness of In the metal sheet approaches the value of the radius of curvature. Complex three-dimensional material behavior effects cannot be represented precisely as the result of the simplified kinematics. Here we present a model adaptivity scheme based on a model error indicator. The model-adaptive technique presented in this paper aides to resolve only the critical areas of the structure with a three-dimensional discretization while keeping reasonable computational cost by utilizing shell elements for the rest of the structure. The model error indicator serves as a guide for subsequent automatic adaptive re-meshing of the work-piece followed by a model-adaptive finite element analysis. The accuracy of the approximation obtained by the model-adaptive technique coincides well with that of a more expensive solution obtained with solid elements only. KW - Finite elements KW - Model adaptivity KW - Coupled analysis KW - Model error KW - Sheet metal forming Y1 - 2010 U6 - https://doi.org/10.1016/j.finel.2010.02.006 VL - 46 IS - 7 SP - 585 EP - 600 ER - TY - GEN A1 - Dendorfer, Sebastian T1 - The influence of modeling parameters in the AnyBody Modeling System on muscle and joint loading in the shoulder T2 - International Shoulder Group Meeting Y1 - 2021 VL - 05 ER - TY - PAT A1 - Schubert, Martin J. W. A1 - Seign, Stefan T1 - Arrangement for Measuring Capacitance Y1 - 2016 ER - TY - JOUR A1 - Lee, Wai-Kong A1 - Schubert, Martin J. W. A1 - Ooi, Boon Yaik A1 - Ho, Stanley Jian-Qin T1 - Multi-source energy harvesting and storage for floating wireless sensor network nodes with Long Range Communication Capability JF - IEEE Transactions on Industry Applications N2 - Wireless sensor networks are widely used for environmental monitoring in remote areas. They are mainly composed of wireless sensor nodes, usually powered by batteries with limited capacity, but are expected to communicate in long range and operate for extended time periods. To overcome these limitations, many energy harvesting techniques are proposed to power wireless nodes for prolonged operation, whereas multihop techniques are utilized to extend the communication range. In this paper, a novel floating device with multisource energy harvesting technology that can be used as a wireless sensor node is proposed. The long range communication between wireless sensor nodes and a gateway is established through LoRa technology. In addition to conventional solar panels, an energy harvesting technique based on thermoelectric generators exploiting thermal differences created between water surface and materials exposed to sunlight is proposed. Energy generated from photovoltaic and thermoelectric generators is combined to power the wireless sensor node. This floating device consumes 6.6216 Wh per day when used as a wireless sensor node for the collection and transmission of environmental data. The sensor node can operate on a water surface for at least 9.6 days when it is not exposed to sunlight. During a sunny day, the floating device can harvest 8.375 Wh from solar panels and 0.425 Wh from thermoelectric generation. In other words, the floating device harvests sufficient energy to be self-sustaining during sunny days. KW - Wireless sensor networks KW - Energy harvesting KW - floating device KW - LoRa KW - sensor node KW - solar energy KW - thermoelectric generation Y1 - 2018 U6 - https://doi.org/10.1109/TIA.2018.2799 VL - 54 IS - 3 SP - 2606 EP - 2615 PB - IEEE ER - TY - CHAP A1 - Lee, Wai-Kong A1 - Schubert, Martin J. W. A1 - Ho, Stanley Jian-Qin T1 - Multi-source energy harvesting and storage for floating wireless-sensor-network nodes T2 - 2016 IEEE Industrial Electronics and Applications Conference (IEACon 2016), 20.-22. Nov. 2016, Kota Kinabalu, Malaysia Y1 - 2016 SN - 9781509009268 ER - TY - CHAP A1 - Schubert, Martin J. W. T1 - System Contemplations for Precision Irrigation in Agriculture T2 - AIP Conference Proceedings N2 - This communication contemplates political, biological and technical aspects for efficient and profitable irrigation in sustainable agriculture. A standard for irrigation components is proposed. The need for many, and three-dimensionally distributed, soil measurement points is explained, thus enabling the control of humidity in selected layers of earth. Combined wireless and wired data transmission is proposed. Energy harvesting and storage together with mechanical sensor construction are discussed. Y1 - 2017 SN - 9780735414969 U6 - https://doi.org/10.1063/1.4979393 VL - 1828 IS - 1 ER - TY - JOUR A1 - Schubert, Martin J. W. T1 - An Analog Node Model for VHDL Based Simulation of RF Integrated Circuits JF - IEEE Transactions on Circuits and Systems I, Regular Papers N2 - This paper describes a very-high-speed integrated-circuit hardware description language (VHDL)-based analog-node model, an associated driver component for the mixed-signal event-driven (MixED) simulation technique, and some primitive device models applied to radio-frequency integrated circuits. With the presented MixED method, analog circuits are modeled as a composition of controlled sources. Unlike other VHDL-based analog simulation methods, these MixED sources compute not only a real number representing an output voltage but also an output impedance. This allows the outputs of several MiXED sources to be connected in order to drive the same node signal n . The voltage of this record-type signal is automatically computed at its element n . u by resolution functions in compliance with Kirchhoff's current law. The data structure of the node signal n , its self-defined resolution functions, and an associated driver component are presented and discussed to meet different simulation requirements, such as speed, versatility, current accuracy, and adaptive time stepping. Several examples demonstrate how to behaviorally model mixed-signal components with this method with an emphasis on the simulation of a heterodyne receiver. Simulation speeds are compared to VHDL-AMS tools. KW - Integrated circuit modeling KW - Radio frequency KW - Analog integrated circuits KW - Radiofrequency integrated circuits KW - Computational modeling KW - Circuit simulation KW - Voltage KW - Signal resolution KW - Hardware design languages KW - Driver circuits Y1 - 2009 U6 - https://doi.org/10.1109/TCSI.2009.2027799 VL - 56 IS - 12 SP - 2717 EP - 2727 ER - TY - CHAP A1 - Schubert, Martin J. W. T1 - VHDL Based Simulation of a Delta-Sigma A/D Converter Clocked with a Phase-Locked Loop T2 - Design, Automation and Test in Europe, DATE'2001 Conference, March 13-16 2001, Munich N2 - The VHDL based mixed-signal event-driven (MixED) simulation method is employed to simulate a comprehensive system containing a number of mixed-signal building blocks: an analog waveform generator, a phase-locked loop and two ∆Σ modulators for A/D conversion. Y1 - 2001 UR - https://hps.hs-regensburg.de/~scm39115/homepage/research/mixed/mixed_publications/2001_date_pll_sigmadelta.pdf ER - TY - CHAP A1 - Bartsch, Ernst A1 - Schubert, Martin J. W. T1 - Mixed Analog-Digital Circuit Modeling Using Event-Driven VHDL T2 - IEEE/VIUF International Workshops on Behavioral Modeling and Simulation (BMAS'97), Ocotober 20/21 1997, Washington D.C., USA N2 - The mixed-signal event-driven (MixED) method developed to simulate small portions of analog circuitry within a digital environment is demonstrated in a mixed signal application. The MixED models using concurrent iteration to account for analog nodes were coded and run in standard VHDL’93. Networks containing linear components such as sources, resistors, capacitors, inductors and operational amplifiers are presented. The possibility to manipulate resistors during runtime is used to simulate switches. Y1 - 1997 UR - https://hps.oth-regensburg.de/scm39115/homepage/research/mixed/mixed_publications/1997_bmas_circuit.pdf ER - TY - CHAP A1 - Schubert, Martin J. W. T1 - Operational Amplifier Modeling Using Event-Driven VHDL T2 - IEEE/VIUF International Workshops on Behavioral Modeling and Simulation (BMAS'97), October 20/21 1997, Washington D.C., USA N2 - A method to model high-gain feedback-loop analog amplifiers on an event driven timeaxis is presented. The demonstrator is coded in digital VHDL’93. In the event-driven scheme any node in the network must converge „on its own“ based on the information delivered from its neighbors, as no overall matrix is set up. For this reason signalloops with a loop gain larger than one are typically unstable. This communication presents a numerically stable generic model for high gain amplifiers with a userdefined feedback network. Non-ideal effects like offset or finite gain can be taken into account. Y1 - 1997 UR - https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.495.5356&rep=rep1&type=pdf ER - TY - PAT A1 - Schubert, Martin J. W. T1 - Feedback-nach-Feedforward-Transformation zur Verhaltensmodellierung rückgekoppelter Verstärker Y1 - 1997 ER - TY - CHAP A1 - Martins-Wagner, Magda A1 - Wagner, Marcus A1 - Haufe, André A1 - Liebold, Christian T1 - A Graphical User Interface for Simulating Resin-Transfer-Molding Combining LS-DYNA and OpenFOAM T2 - 10th European LS-DYNA Conference 2015, Würzburg, Germany N2 - The paper describes parts of the joint research project Swim-RTM including several industrial and academic partners. Its goal is to combine LS-DYNA and the open-source CFD solver OpenFOAM to simulate the production process of continuous fiber-reinforced plastics, particularly the resin-transfer-molding (RTM) process, in which the layers of dry fabric (unidirectional or woven) are formed in the mold (draping) and then filled with liquid resin with high pressure at injection points. Through a combined analysis of both the structural mechanical and the fluid dynamical phases, a better prediction and thereby optimization of the textile components properties as well as injection points can be achieved, improving the manufacturing process. The draping simulation of the fabric layers is carried out with LS-DYNA, while the injection simulation of the matrix material is performed in full 3D with OpenFOAM. A key question in this research project is how local porosities can be derived from the structural computation in the draping step. The purpose of the presented subproject is to develop a graphical user interface (GUI) to enable the simulation of the entire RTM process of long-fiber-reinforced components including the transfer of results between the draping and injection phases. The complete simulation task is relatively complex and involves several software packages, meaning a high effort for the user to get familiarized with. To circumvent this, the GUI aims at requiring from the user only the minimum necessary input data, creating and running the simulation and mapping tasks in the background, and showing graphically all demanded intermediate and final results. For the draping step several current fabric materials such as *MAT_034, *MAT_234, *MAT_235, *MAT_249 are available. Several modelling techniques for the composite setup are also conceivable, including a workflow similar to metal forming applications. In the injection step the fabric is modelled as a porous medium and different transport models and liquid resin types are at hand. For the data transfer between the draping and injection models, i.e. the mapping of data between shell and volume meshes within the developed GUI, first the OpenFOAM volume mesh is converted to LS-DYNA format and the necessary passing parameters are extracted from the output files, then the mapping tool DYNAmap [3] from DYNAmore GmbH is invoked, and finally the OpenFOAM command files are created. After the injection simulation is started and successfully terminated, information, such as the distribution of air inclusions or the shear stress distribution to analyze the reorientation of component fibers, is available and can be transferred from the 3D fluid mesh to an LS-DYNA shell mesh for further computations, for instance a crash simulation. This backward data mapping between volume and shell meshes can then be performed inside the GUI. Y1 - 2015 UR - https://www.researchgate.net/publication/280836408_A_Graphical_User_Interface_for_Simulating_Resin-Transfer-Molding_Combining_LS-DYNA_and_OpenFOAM ER - TY - RPRT A1 - Emmert, Michael A1 - Glück, Sven A1 - Freilinger, Eva A1 - Brandl, Dominik A1 - Schindler, Sebastian A1 - Kaul, Nicolas A1 - Rasp, Franziska A1 - Akstaller, Monika A1 - Wetzel, Daniel A1 - Jupke, Michael A1 - Bodensteiner, Michael A1 - Hohlfeld, Philipp A1 - Böhm, Kevin A1 - Brem, Theresa A1 - Hammer, Pascal A1 - Singer, Thomas A1 - Karing, Maria A1 - Schneider, Viola A1 - Ostermeier, Tobias ED - Meier, Hans ED - Niemetz, Michael ED - Reindl, Andrea T1 - FMS-Berichte (Mai 2021) BT - Seminar zu aktuellen Themen der Elektro- und Informationstechnik N2 - Dieser Bericht entstand auf Initiative der Studierenden des 2020 neu gegründeten Masterstudiengangs „Elektro- und Informationstechnik (MEI)“, die an der Pflichtlehrveranstaltung „Forschungsmethoden und Seminar (FMS)“ im Wintersemester 2020/21 teilnahmen. Diese Lehrveranstaltung hat das Ziel, systematisch an das wissenschaftliche Arbeiten, speziell die Wissenschaftskommunikation, heranzuführen. Daher war geeignete Literatur zu einem individuellen Thema zu recherchieren, Veröffentlichungen auf ihre Relevanz hin zu beurteilen und letztendlich eine eigene Ausarbeitung basierend auf der Literaturrecherche zu erarbeiten und diese in einem Vortrag zu präsentieren. Parallel dazu erfolgte im Theorieteil die entsprechende Hinführung zu den verschiedenen Elementen der Wissenschaftskommunikation: • Bedeutung der Wissenschaftskommunikation für die Arbeit der Ingenieure in Forschung und Entwicklung • Literaturrecherche, Suchmaschinen, Sichtung und Analyse vorhandener Publikationen, Bewertung der Qualität aufgefundener Fachliteratur, Auswahl geeigneter Materialien für die eigene Arbeit • Aufbereitung und Darstellung der recherchierten technischer Inhalte in Form einer seitenanzahlbegrenzten wissenschaftlichen Ausarbeitung • Einhalten formaler Randbedingungen bzgl. Strukturierung, einschl. Bildnachweise und Zitationsstile • Peer-review-Prozess bei wertschätzender Beurteilung der Leistung anderer • Publikumsangepasstes Aufbereiten komplexer fachlicher Inhalte mit hochschulöffentlicher Präsentation der Ergebnisse • Führen mündlicher wissenschaftlicher Diskurse Nachdem die Masterstudierenden in der Regel über noch keine eigene wissenschaftliche Forschungserfahrung bzw. -inhalte verfügen, lag der wählbare Schwerpunkt der Literatursuche auf der Bearbeitung von vorgegeben aktuellen technischen oder gesellschaftspolitischen Forschungsthemen. T3 - Forschungsmethoden-Seminar - 1 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-19155 CY - Regensburg ER - TY - CHAP A1 - Schubert, Martin J. W. A1 - Blödel, J. A1 - Conradi, P. A1 - Lafosse, P. A1 - Nebel, W. A1 - Neusser, S. A1 - Ryba, M. A1 - Schröder, D. T1 - Extending EDIF for Technology Data T2 - EDIF World Conference, 1989, San Jose, CA, USA, 11.-14. September Y1 - 1989 ER - TY - CHAP A1 - Schubert, Martin J. W. A1 - Seign, Stefan A1 - Dai, Q. A1 - Hinterseer, Sebastian A1 - Pielmeier, F. A1 - Pietsch, Alexander A1 - Seebauer, C. A1 - Weiß, Josef A1 - Yu, C. A1 - Zenger, Stefan T1 - Capacitive Sensor Technology for Soil Moisture Monitoring Networks T2 - 24th IEEE International Conference on Electronics, Circuits and Systems (ICECS), 5-8 Dec. 2017, Batumi, Georgia N2 - A sensor technology for tracking soil-moisture in agricultural fields is presented. A linear measurement method was developed to satisfy the need for cheap sensors with wide range of capacitance change such as factor 30. A combined wired and wireless network transmits data to a server. Various battery aspects are compared with respect to use in agriculture. Y1 - 2017 U6 - https://doi.org/10.1109/ICECS.2017.8292018 SP - 190 EP - 193 ER - TY - CHAP A1 - Schubert, Martin J. W. T1 - Mixed-Signal Event-Driven Simulation of a Phase-Locked Loop T2 - IEEE/VIUF International Workshops on Behavioral Modeling and Simulation (BMAS'99), October 4-6 1999, Orlando, Florida, USA N2 - The mixed-signal event-driven (MixED) simulationalgorithm using standard VHDL is capable of modelinga number of analog and mixed-signal problems in digital circuits, e.g. RCL networks representing pads or wires, charge pumps, dynamic logic, voltage-controlledoscillators, phase-locked loops, etc. Important featuresare single-kernel simulation as well as rapid A/D andD/A interfacing. This paper demonstrates the simulation of a phase-locked loop (PLL), which is one of the most interesting applications of the MixED method. Many digital designs contain a PLL as only mixed-signal building block. The MixED method allows to simulate such designs with standard VHDL. KW - mixed-signal event-drivensimulation KW - standard VHDL KW - analog models KW - PLL Y1 - 1999 UR - https://hps.hs-regensburg.de/~scm39115/homepage/research/mixed/mixed_publications/1999_bmas_pll.pdf ER - TY - CHAP A1 - Schubert, Martin J. W. T1 - VHDL Based Simulation of a Sigma-Delta A/D Converter T2 - EEE/ACM International Workshop on Behavioral Modeling and Simulation (BMAS2000), October 19-20 2000, Orlando, Florida, USA, prodeedings N2 - The VHDL based mixed-signal event-driven (MixED) simulation method is employed to simulate a sigma-delta modulator for A/D conversion. Results are verified by experimental data and comparison to PSpice-AD simulations. Y1 - 2000 U6 - https://doi.org/10.1109/BMAS.2000.888367 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 - 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 - 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 - Lang, Christian A1 - Steinborn, Florian A1 - Steffens, Oliver A1 - Lang, Elmar Wolfgang T1 - Electricity Load Forecasting - An Evaluation of Simple 1D-CNN Network Structures T2 - International Conference on Time Series and Forecasting (ITISE 2019), Proceedings of Papers Vol. 2, 25-27 September 2019, Granada (Spain) N2 - This paper presents a convolutional neural network (CNN)which can be used for forecasting electricity load profiles 36 hours intothe future. In contrast to well established CNN architectures, the inputdata is one-dimensional. A parameter scanning of network parameters isconducted in order to gain information about the influence of the kernelsize, number of filters, and dense size. The results show that a goodforecast quality can already be achieved with basic CNN architectures.The method works not only for smooth sum loads of many hundredconsumers, but also for the load of apartment buildings KW - energy load forecasting KW - STLF KW - neural networks KW - CNN KW - con-volutional networks Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-16649 UR - https://arxiv.org/abs/1911.11536 UR - http://itise.ugr.es/ITISE2019_vol2.pdf SN - 978-84-17970-78-9 SP - 797 EP - 806 ER - TY - JOUR A1 - Visscher, Rosa A1 - Wyss, C. A1 - Singh, Navrag B. A1 - Taylor, William R. A1 - Dendorfer, Sebastian A1 - Rutz, E. A1 - Brunner, Reinald T1 - Influence of TAL-TATS surgery on energy production of Tricepts Surae - A musculoskeletal modeling evaluation JF - Gait & Posture Y1 - 2020 U6 - https://doi.org/10.1016/j.gaitpost.2020.08.090 VL - 81 IS - Suppl. 1 SP - 381 EP - 382 PB - Elsevier ER - TY - JOUR A1 - Kramer, Sharlotte L. B. A1 - Jones, Amanda A1 - Mostafa, Ahmed A1 - Ravaji, Babak A1 - Tancogne-Dejean, Thomas A1 - Roth, Christian C. A1 - Nonn, Aida T1 - The third Sandia fracture challenge: predictions of ductile fracture in additively manufactured metal JF - International Journal of Fracture N2 - The Sandia Fracture Challenges provide a forum for the mechanics community to assess its ability to predict ductile fracture through a blind, round-robin format where mechanicians are challenged to predict the deformation and failure of an arbitrary geometry given experimental calibration data. The Third Challenge (SFC3) required participants to predict fracture in an additively manufactured (AM) 316L stainless steel bar containing through holes and internal cavities that could not have been conventionally machined. The volunteer participants were provided extensive data including tension and notched tensions tests of 316L specimens built on the same build-plate as the Challenge geometry, micro-CT scans of the Challenge specimens and geometric measurements of the feature based on the scans, electron backscatter diffraction (EBSD) information on grain texture, and post-test fractography of the calibration specimens. Surprisingly, the global behavior of the SFC3 geometry specimens had modest variability despite being made of AM metal, with all of the SFC3 geometry specimens failing under the same failure mode. This is attributed to the large stress concentrations from the holes overwhelming the stochastic local influence of the AM voids and surface roughness. The teams were asked to predict a number of quantities of interest in the response based on global and local measures that were compared to experimental data, based partly on Digital Image Correlation (DIC) measurements of surface displacements and strains, including predictions of variability in the resulting fracture response, as the basis for assessment of the predictive capabilities of the modeling and simulation strategies. Twenty-one teams submitted predictions obtained from a variety of methods: the finite element method (FEM) or the mesh-free, peridynamic method; solvers with explicit time integration, implicit time integration, or quasi-statics; fracture methods including element deletion, peridynamics with bond damage, XFEM, damage (stiffness degradation), and adaptive remeshing. These predictions utilized many different material models: plasticity models including J2 plasticity or Hill yield with isotropic hardening, mixed Swift-Voce hardening, kinematic hardening, or custom hardening curves; fracture criteria including GTN model, Hosford-Coulomb, triaxiality-dependent strain, critical fracture energy, damage-based model, critical void volume fraction, and Johnson-Cook model; and damage evolution models including damage accumulation and evolution, crack band model, fracture energy, displacement value threshold, incremental stress triaxiality, Cocks-Ashby void growth, and void nucleation, growth, and coalescence. Teams used various combinations of calibration data from tensile specimens, the notched tensile specimens, and literature data. A detailed comparison of results based of these different methods is presented in this paper to suggest a set of best practices for modeling ductile fracture in situations like the SFC3 AM-material problem. All blind predictions identified the nominal crack path and initiation location correctly. The SFC3 participants generally fared better in their global predictions of deformation and failure than the participants in the previous Challenges, suggesting the relative maturity of the models used and adoption of best practices from previous Challenges. This paper provides detailed analyses of the results, including discussion of the utility of the provided data, challenges of the experimental-numerical comparison, defects in the AM material, and human factors. KW - Fracture KW - Rupture KW - Tearing KW - Deformation KW - Plasticity KW - Metal KW - Alloy KW - Additive manufacturing KW - Simulation KW - Prediction KW - Modeling Y1 - 2019 U6 - https://doi.org/10.1007/s10704-019-00361-1 VL - 218 SP - 5 EP - 61 PB - Springer Nature ER - TY - THES A1 - Romano, Marco T1 - Charakterisierung von gewebeverstärkten Einzellagen aus kohlenstofffaserverstärktem Kunststoff (CFK) mit Hilfe einer mesomechanischen Kinematik sowie strukturdynamischen Versuchen N2 - Die vorliegende Arbeit behandelt die analytische und numerische Identifikation einer mesomechanischen Kinematik in gewebeverstärkten Einzellagen sowie deren Validierung über die Strukturdynamik von flachen stabförmigen Probekörpern aus kohlenstofffaserverstärktem Kunststoff (CFK). Unter der Voraussetzung, dass das wiederholte Wirken der Kinematik Energie dissipiert, trägt sie bei zyklischer viskoelastischer Deformation zusätzlich zur reinen viskoelastischen Werkstoffdämpfung in gewebeverstärkten Einzellagen bei. Die analytischen und numerischen Untersuchungen beschränken sich auf die Betrachtung des ebenen, zweidimensionalen Zusammenhangs einer vollständigen Ondulation bzw. einer repräsentativen Sequenz in Dickenrichtung. Zur Parameteridentifikation werden die geometrischen Abmessungen in definierten Schritten variiert. Dafür wird der Grad der Ondulation in gewebeverstärkten Einzellagen Õ=A/L als dimensionslose Kennzahl eingeführt. Zur Validierung der dämpfungserhöhenden Wirkung der in den analytischen und numerischen Untersuchung identifizierten mesomechanischen Kinematik in gewebeverstärkten Einzellagen werden in experimentellen strukturdynamischen Untersuchungen frei abklingende Transversalschwingungen von einseitig fest eingespannten Probekörpern untersucht. Im Detail werden flache stabförmige Probekörper aus kohlenstofffaserverstärktem Epoxidharz mit Lagenaufbauten aus 0°-unidirektionalen und gewebeverstärkten Einzellagen untersucht. Die Ergebnisse der experimentellen strukturdynamischen Untersuchungen dienen schließlich der Validierung des analytischen Modells und der numerischen Berechnungen. Die dämpfungserhöhende Wirkung der identifizierten mesomechanischen Kinematik wird schließlich in Abhängigkeit des eingeführten Grades der Ondulation Õ quantifiziert. KW - faserverstärkte Kunststoffe KW - CFK KW - Mesomechanik KW - Leinwandgewebe KW - Köpergewebe 2/2 KW - Ondulation KW - Grad der Ondulation KW - Strukturdynamik KW - Dämpfung KW - Werkstoffdämpfung; KW - flache stabförmige Probekörper KW - Kragbalken Y1 - 2017 SN - 978-3-8440-5177-3 U6 - https://doi.org/10.2370/9783844051773 PB - Shaker CY - Aachen ER - TY - THES A1 - Putzer, Michael T1 - Development of subject-specific musculoskeletal models for studies of lumbar loading N2 - Anatomical differences between individuals are often neglected in musculoskeletal models, but they are necessary in case of subject-specific questions regarding the lumbar spine. A modification of models to each subject is complex and the effects on lumbar loading are difficult to assess. The objective of this thesis is to create a validated musculoskeletal model of the human body, which facilitates a subject-specific modification of the geometry of the lumbar spine. Furthermore, important parameters are identified in sensitivity studies and a case study regarding multifidus muscle atrophy after a disc herniation is conducted. Therefore, a generic model is heavily modified and a semi-automatic process is implemented. This procedure remodels the geometry of the lumbar spine to a subject-specific one on basis of segmented medical images. The resulting five models are validated with regard to the lumbar loading at the L4/L5 level. The influence of lumbar ligament stiffness is determined by changing the stiffness values of all lumbar ligaments in eleven steps during a flexion motion. Sensitivities of lumbar loading to an altered geometry of the lumbar spine are identified by varying ten lumbar parameters in simulations with each model in four postures. The case study includes an analysis of the loading of the multifidus muscle and of the lumbar discs throughout various stages of disc herniation. This time each model performs four motions with two different motion rhythms. The results indicate that lumbar motion and loading is dependent on lumbar ligament stiffness. Furthermore, subject-specific modelling of the lumbar spine should include at least the vertebral height, disc height and lumbar lordosis. The results of the case study suggest that an overloading of the multifidus muscle could follow disc herniation. Additionally, a subsequent atrophy of the muscles could expose adjacent levels to an increased loading, but these findings are highly dependent on the individual. KW - Lendenwirbelsäule KW - Geometrie KW - Lendenwirbelsäulenkrankheit KW - Computertomografie KW - Modell KW - Hochschulschrift Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:706-5924 N1 - Kooperative Promotion an der Fakultät Maschinenbau der Ostbayerischen Technischen Hochschule Regensburg (OTH.R) im Labor für Biomechanik (LBM) bei Prof. Dr.-Ing. Sebastian Dendorfer und Labor für Faserverbundtechnik (LFT) bei Prof. Dr.-Ing. Ingo Ehrlich ER - TY - CHAP A1 - Wätzig, A. A1 - Schmid, Vinzent A1 - Ehrlich, Ingo ED - Mottok, Jürgen ED - Reichenberger, Marcus ED - Stolle, Reinhard T1 - Damage Modelling of Adhesive Joints Using the Cohesive Zone Model T2 - Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016 Y1 - 2016 PB - Pro Business Verlag CY - Berlin ER - TY - JOUR A1 - Valentino, Piergiorgio A1 - Sgambitterra, Emanuele A1 - Furgiuele, Franco A1 - Romano, Marco A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Mechanical characterization of basalt woven fabric composites BT - numerical and experimental investigation JF - Frattura ed Integrità Strutturale (Fracture and Structural Integrity) N2 - Basalt fabric composite, with different twill wave reinforcements, i.e. twill 2/2 and twill 1/3, have been studied in this work by means of experimental tests and numerical finite element (FE) simulations. As fabric reinforcements show repeating undulations of warp and fill yarn, simple mixtures law cannot be applied. As a consequence, the mesoscopic scale, lying between the microscopic and the macroscopic one, has to be taken into account to mechanically characterize a fabric reinforced composite. The aim of this work is to evaluate the stiffness of a fabric reinforced composite in warp and fill direction. In particular a numerical FE model, assuming elliptical sections and sinusoidal shape of the yarns, has been implemented and experimental tests have been carried out in order to validate the proposed model. Finally, the strength and the failure modes le orientation, have been experimentally investigated. Y1 - 2014 U6 - https://doi.org/10.3221/IGF-ESIS.28.01 VL - 8 IS - 28 SP - 1 EP - 11 ER - TY - JOUR A1 - Siegl, Marco A1 - Ehrlich, Ingo T1 - Transformation of the Mechanical Properties of Fiber-Reinforced Plastic Tubes from the Cartesian Coordinate System into the Cylindrical Coordinate System for the Application of Bending Models JF - Athens Journal of Technology & Engineering N2 - Fiber-reinforced plastic (FRP) tubes are used in many different industries, such as electrical engineering and pipeline construction. The tubes are frequently subjected to bending loads, depending on the application. In order that the dimensioning of the tubes can be ensured, analytical bending models are used to calculate the resulting stresses, strains and displacements in the individual layers of the laminate. This enables the making of a statement about the failure of the fiber-reinforced tube by choosing an appropriate failure criterion. For the use of these bending models, it is necessary to understand the respective underlying theory. The theory provides the basis for the mathematical description of the mechanical properties for a single-layered tube and using the relationships between the stresses and strains that occur in the Cylindrical coordinate system for this calculation step. For this reason, a redefinition of the compliance matrix from the transformation about the winding angle to the Cylindrical coordinate system and a modification of the stress and strain vectors is necessary, because the defined Cartesian coordinate system of the model cannot be used for wounded FRP tubes. The transformation causes an exchange of entries in the compliance matrix, which remain in the correct relationship between the particular stress and strains. This step is not specified and may lead to incorrect results due to the incorrect entry of compliances. The present publication refers to sketch on this issue and represent a simplification of the changeover to the level required by the bending models notation of vectors in the form of a permutation. In addition, a new name for the pre-acquisition of the redefined compliances is given to prevent confusion when entering the material law of a bending model. Finally, the permuted and redefined compliances are proved in an example to determine their accuracy. KW - Bending model KW - Cylindrical coordinate system KW - Fiber-reinforced plastic tubes KW - Permutation of the compliances KW - Transformation of the compliances Y1 - 2017 UR - https://www.athensjournals.gr/technology/2017-4-1-4-Siegl.pdf VL - 4 IS - 1 SP - 47 EP - 62 ER - TY - JOUR A1 - Romano, Marco A1 - Eisenried, Michael A1 - Jungbauer, Bastian A1 - Ehrlich, Ingo A1 - Gebbeken, Norbert T1 - Influence of parameters of the production process on the material quality of unidirectionally reinforced prepregs JF - Journal of Achievements in Materials and Manufacturing Engineering (JAMME) N2 - Purpose: A prepreg production device in laboratory scale is used to develop the production process of unidirectionally reinforced prepregs. Design/methodology/approach: The aim of the prepreg production device is to impregnate different types of reinforcement fibers with an arbitrarily selectable thermoset matrix system that completely satisfies the requirements for autoclave processing. As the prepreg production device is designed and built up modularly every module corresponds one step in the process. Findings: To identify the parameters of the production process and investigate its sensitivity on the material quality of both the prepreg as an uncured semi-finished product and the composite as the cured material experimental investigations regarding the resin flow, fiber volume content, mass per unit area and void content are carried out. Overall four material combinations have been investigated, where in each case the selected impregnation temperature and the width of the impregnation gap has been reproducibly varied in selected steps. Research limitations/implications: The experimental characterization of the prepregs and of the composite material is carried out according to German standards. Y1 - 2015 UR - http://jamme.acmsse.h2.pl/vol68_1/6815.pdf VL - 68 IS - 1 SP - 32 EP - 44 ER - TY - CHAP A1 - Pongratz, Christian A1 - Ehrlich, Ingo ED - Mottok, Jürgen ED - Reichenberger, Marcus ED - Stolle, Reinhard T1 - Structural Dynamic Analysis of Thin Composite Plates Using Noncontact Measurement and Excitation T2 - Applied Research Conference 2016 - ARC 2016, Augsburg, 24 June 2016 Y1 - 2016 SN - 978-3-86460-494-2 SP - 351 EP - 358 PB - Pro Business Verlag CY - Berlin ER - TY - JOUR A1 - Rück, Thomas A1 - Bierl, Rudolf A1 - Lechner, Alfred A1 - Graf, Antonia A1 - Dams, Florian A1 - Schreiner, Rupert A1 - Auchter, Eberhard A1 - Kriz, Willy A1 - Deubzer, MIchael A1 - Schiller, Frank A1 - Mottok, Jürgen A1 - Niemetz, Michael A1 - Margull, Ulrich A1 - Hagel, Georg A1 - Utesch, Matthias A1 - Waldherr, Franz A1 - Böhm, Matthias A1 - Fraunhoffer, Judith A1 - Gardeia, Armin A1 - Schneider, Ralph A1 - Streubel, Janet A1 - Landes, Dieter A1 - Studt, Reimer A1 - Peuker, Dominik A1 - Scharfenberg, Georg A1 - Hook, Christian A1 - Schuster, Dietwald A1 - Ehrlich, Ingo A1 - Dinnebier, Heinrich A1 - Briem, Ulrich A1 - Lämmlein, Stephan A1 - Koder, Alexander A1 - Bialek, Adam A1 - Genewsky, Axel A1 - Neumeier, Michael A1 - Schlosser, Philipp A1 - Rabl, Hans-Peter A1 - Paule, Matthias A1 - Galster, Christoph A1 - Schiedermeier, Michael A1 - Zwickel, Andreas A1 - Hobmeier, Christoph A1 - Bischoff, Tobias A1 - Rill, Georg A1 - Schaeffer, Thomas A1 - Arbesmeier, Martin A1 - Groß, Andreas A1 - Schlegl, Thomas A1 - Becker, Mark A1 - Senn, Konrad A1 - Schliekmann, Claus A1 - Scholz, Peter A1 - Sippl, Christian A1 - Grill, Martin ED - Eckstein, Josef T1 - Forschungsbericht 2011 / Hochschule für Angewandte Wissenschaften - Fachhochschule Regensburg T3 - Forschungsberichte der OTH Regensburg - 2011 Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-7321 SN - 1868-3533 CY - Regensburg ER - TY - CHAP A1 - Ławrowski, Robert Damian A1 - Schreiner, Rupert A1 - Linghu, Shuangyi A1 - Gu, Fuxing T1 - Field Emission Behaviour of Single-Crystal Pd Nanowires T2 - 33rd International Vacuum Nanoelectronics Conference (IVNC): 6-10 July 2020, Lyon, France N2 - Single-crystal Pd nanowires with typically 100 nm diameters and lengths from several micrometers to tens of micrometers were grown on Al 2 O 3 substrates in a furnace with Ar atmosphere. Integral field emission measurements of such samples after Pd coating (~10 nm) were performed in a diode configuration with a 50 μm mica spacer in a vacuum chamber at pressures of about 10 -9 mbar. The IV measurement of the sample shows an integral emission current up to 2 μA at a voltage of 500 V (10 MV/m) and an onset voltage for a current of 1 nA of about 275 V. The corresponding Fowler-Nordheim plot show a linear behavior, like expected for a metal needle. Y1 - 2020 SN - 978-1-7281-9454-7 U6 - https://doi.org/10.1109/IVNC49440.2020.9203510 SP - 1 EP - 2 PB - IEEE ER - TY - CHAP A1 - Ławrowski, Robert Damian A1 - Hausladen, Matthias A1 - Schreiner, Rupert T1 - Individually Addressable Fully Integrated Field Emission Electron Source Fabricated by Laser Micromachining of Silicon T2 - 33rd International Vacuum Nanoelectronics Conference (IVNC): 6-10 July 2020, Lyon N2 - A cathode with individually addressable Si tips allows the observation of the activation procedure and emission behaviour of each field emission emitter at any time of the measurement. The cathode consists of an array of 2x2 conically shaped emitter structures, which were fabricated by laser micromachining and wet etching of a Si substrate bonded on a glass carrier. Using the same process, a Si extractions grid was fabricated and mounted onto the emitter. Integral field emission measurements were performed in a diode configuration in a vacuum chamber at pressures of about 10- 9 mbar. The emitters show an onset voltage between 200 V and 300 V. The emission current for each emitter on the cathode was regulated to a given value (1.0 μA, 2.5μA, 5.0μA) by an external regulating circuit and was recorded individually during the measurement. With such approach, the relation between the emission behaviour and the geometry of emitters can be studied in detail. In addition, the current stabilization of each emitters of an array can be investigated, which led to a current stability of better than 0.5%. Y1 - 2020 SN - 978-1-7281-9454-7 U6 - https://doi.org/10.1109/IVNC49440.2020.9203470 SP - 1 EP - 2 PB - IEEE 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 - JOUR A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Ławrowski, Robert Damian A1 - Schreiner, Rupert A1 - Serbun, Pavel A1 - Müller, Günter A1 - Düsberg, Felix A1 - Hofmann, Martin A1 - Bachmann, Michael A1 - Pahlke, Andreas T1 - Field emission properties of p-type black silicon on pillar structures JF - Journal of Vacuum Science & Technology B N2 - Arrays of black silicon field emission pillar structures were fabricated on p-type silicon substrates. Two types of samples with the same number of pillars (arrays of 10 × 10) but different pillar heights (8 and 20 μm) were prepared as well as a black silicon reference sample without pillars. The field emission properties of these cathodes were investigated both by means of integral current-voltage measurements and by field emission scanning microscopy. Samples with a pillar height of 20 μm revealed onset fields as low as 6.4 V/μm, field enhancement factors up to 800, and emission currents up to 8 μA at an applied field of 20 V/μm. Due to the p-type material, a saturation of the emission current for fields above 11 V/μm was observed. This saturation leads to a stable operation with a current fluctuation of less than ±8%. It was found that samples with a pillar height of 20 μm showed improved emission characteristics compared to samples with a pillar height of 8 μm or without pillars. The voltage maps revealed an increased emission homogeneity after a “burn-in” sequence of the sample. The current map showed that a few of the pillars dominate the emission. Integral current stability measurements were performed under different vacuum pressures, in order to investigate altered emission behavior and a potential degradation of the emitters. At pressures above 10−6 mbar, the sample starts to degrade irreversibly. Nevertheless, even after a harsh treatment over 30 min at 5 × 10−5 mbar and at an applied field of 23 V/μm, the cathode was still operating, and did not fail during further operation over 20 h at 5 × 10−8 mbar and at an applied field of 28 V/μm. Y1 - 2016 U6 - https://doi.org/10.1116/1.4943919 VL - 34 IS - 2 ER - TY - JOUR A1 - Mingels, Stephan A1 - Porshyn, Vitali A1 - Prommesberger, Christian A1 - Langer, Christoph A1 - Schreiner, Rupert A1 - Lützenkirchen-Hecht, Dirk A1 - Müller, Günter T1 - Photosensitivity of p-type black Si field emitter arrays JF - Journal of Applied Physics N2 - We have investigated the properties of black Si field emitter arrays under strong electric fields and laser illumination. A low onset field of 1.8 MV/m for an emission current of 1 nA was obtained. A pronounced saturation region of the dark and photo-enhanced current was observed, which provided a short-term stability of 0.1% at 0.4 μA and 0.7% at 1.0 μA, respectively. As maximum value for the photosensitivity, an on-off current switching ratio of 43 reaching about 13 μA was achieved at a laser power of 15 mW. Electron spectra in the dark and under laser illumination are presented, showing a current and light-sensitive voltage drop across the emitters as well as hints for hot electron emission. Y1 - 2016 U6 - https://doi.org/10.1063/1.4948328 VL - 119 IS - 16 ER - TY - JOUR A1 - Bachmann, Michael A1 - Dams, Florian A1 - Düsberg, Felix A1 - Hofmann, Martin A1 - Pahlke, Andreas A1 - Langer, Christoph A1 - Ławrowski, Robert Damian A1 - Prommesberger, Christian A1 - Schreiner, Rupert A1 - Serbun, Pavel A1 - Lützenkirchen-Hecht, Dirk A1 - Müller, Günter T1 - Extraction of the characteristics of current-limiting elements from field emission measurement data JF - Journal of Vacuum Science & Technology B N2 - In this contribution, the authors will present an algorithm to extract the characteristics of nonideal field emission circuit elements from saturation-limited field emission measurement data. The method for calculating the voltage drop on current-limiting circuit elements is based on circuit theory as well as Newton's method. Since the only assumption the authors make on the current-limiting circuit is a connection in series, this method is applicable to most field emission data showing saturation. To be able to determine the significance of any parameter output, the uncertainties of data and extracted parameters as well as the parameter correlations are fully taken into account throughout the algorithm. N-type silicon samples with varying external serial resistors are analyzed. All results show a good agreement to the nominal resistor values. Additionally, several p-type samples are analyzed, showing a diodelike behavior. The extracted current-limiting characteristics of the p-type samples are in good agreement with a pn-junction model. The stability of the emission current of the p-type samples is measured by constant voltage measurements and compared to the extracted current-limiting characteristics. The application of the algorithm to measurement data shows that the given algorithm is a valuable tool to analyze field emission measurement data influenced by nonemissive processes. Y1 - 2017 U6 - https://doi.org/10.1116/1.4971768 VL - 35 IS - 2 ER - TY - JOUR A1 - Prommesberger, Christian A1 - Bachmann, Michael A1 - Düsberg, Felix A1 - Langer, Christoph A1 - Ławrowski, Robert Damian A1 - Hofmann, Martin A1 - Pahlke, Andreas A1 - Schreiner, Rupert T1 - Regulation of the Transmitted Electron Flux in a Field-Emission Electron Source Demonstrated on Si Nanowhisker Cathodes JF - IEEE Transactions on Electron Devices N2 - We report on a method to stabilize the transmitted electron flux in a field-emission electron source using an external regulation circuit. The electron source was realized with an array of silicon (Si) nanowhiskers on the top of elongated pillar structures, a mica spacer, and an extraction grid made of Si. As for most applications, the emitted electron current from the cathode is not as crucial as the transmitted electron flux through the extraction grid toward the anode. We investigated a method which allows the regulation directly by the emitted electron flux and not merely on the cathode current. By using this method, we were able to stabilize the emitted electron flux of our electron source down to values below 1%. Simultaneously, it was shown that there is the possibility to stabilize the influencing value in the real application as well. The effectiveness of this method was demonstrated successfully with an X-ray source setup. The measured X-ray photon count rate was stabilized to a standard deviation of 0.30% at a pressure of 1 × 10 -7 mbar. Even in harsh environment of 2 × 10 -5 mbar, a stabilization of the X-ray photon count rate down to a value of 0.63% was achieved. KW - Cathodes KW - Nanostructured devices KW - Current measurement KW - Photonics KW - Electron sources KW - Emissions KW - Voltage measurement Y1 - 2017 U6 - https://doi.org/10.1109/TED.2017.2763239 SN - 5128-5133 VL - 64 IS - 12 PB - IEEE ER - TY - CHAP A1 - Lindner, Matthias A1 - Berndt, Dominik A1 - Jungbauer, Bastian A1 - Ehrlich, Ingo A1 - Schreiner, Rupert A1 - Pipa, Andrei V. A1 - Hink, Rüdiger A1 - Foest, Rüdiger A1 - Brandenburg, Ronny A1 - Max, Alexander A1 - Caspari, Ralf T1 - Fabrication, surface integration and testing of miniaturized dielectric barrier discharge plasma actuators for active flow control applications T2 - AIAA Aviation 2019 Forum, 17-21 June 2019, Dallas, Texas Y1 - 2019 U6 - https://doi.org/10.2514/6.2019-2998 ER - TY - CHAP A1 - Lindner, Matthias A1 - Berndt, Dominik A1 - Tschurtschenthal, Karl A1 - Ehrlich, Ingo A1 - Jungbauer, Bastian A1 - Schreiner, Rupert A1 - Pipa, Andrei V. A1 - Hink, Rüdiger A1 - Foest, Rüdiger A1 - Brandenburg, Ronny A1 - Neuwirth, Daniel A1 - Karpen, Norbert A1 - Bonaccurso, Elmar A1 - Weichwald, Robert A1 - Max, Alexander A1 - Caspari, Ralf T1 - Aircraft Icing Mitigation by DBD-based Micro Plasma Actuators T2 - AIAA AVIATION 2020 FORUM: June 15-19, 2020 N2 - We present the application of plasma actuators as a technology for ice prevention at airfoils. The miniaturized dielectric barrier discharge (DBD) plasma actuators (PA) were fabricated by means of microelectromechanical systems (MEMS). We elucidate how to make the actuator samples scalable and applicable to any desired shape by the use of flexible inorganic zirconia substrates. For this purpose, we applied our developed embedding method to integrate the micro actuators in modern carbon/glass fiber reinforced polymer (CFRP/GFRP) materials. Next, the embedded actuator samples were mounted on a mechanical air profile-like fixture and placed in the icing wind tunnel iCORE. The samples were tested in rime ice conditions at temperatures of -15 to -20° C and air speeds up to 30 m/s. Unlike other groups we used a thin film zirconia substrate as dielectric for the plasma actuator. Due to the low substrate thickness of just 150 µm, an operating voltage of 2 kVRMS is already sufficient enough for a stable plasma formation. The experiments show that the operated actuator was able to prevent the ice formation and first indications of a De-icing function were also found. Hence, we show that it is feasible to realize an anti-icing system with zirconia-based plasma actuators operated at lower voltages compared to conventional ones. Y1 - 2020 U6 - https://doi.org/10.2514/6.2020-3243 ER - TY - JOUR A1 - Herrmann, Frank A1 - Büttner, Simon T1 - Automatische Qualitätskontrolle mittels Maschinellem Lernen und SAP Leonardo JF - Anwendungen und Konzepte der Wirtschaftsinformatik N2 - In vielen Unternehmen werden von Menschen durch Ansehen von Produkten Produktionsfehler identifiziert. Die übersehenen Produktionsfehler führen zunehmend häufiger zu teuren Kundenreklamationen. Für die Produktion von Fußbällen wird in dieser Arbeit diese manuelle Qualitätssicherung analysiert. Als Alternative werden die Fußbälle durch einen Roboter fotografiert u nd durch maschinelles Lernen werden Produktionsfehler auf diesen digitalen Fotos identifiziert. Dieser Prüfprozess wird in SAP Leonardo implementiert und damit wird der bereits in einem SAP System implementierte Produktionsprozess (bzw. Unternehmensprozess) erweitert, wodurch ein durchgängig digitalisierter Gesamtprozess implementiert wird. Dadurch werden signifikant bessere Prüfergebnisse erreichtb und die Durchlaufzeit des Prüfprozesses wird substantiell reduziert. KW - Industrie 4.0 KW - SAP Leonardo KW - SAP S/4HANA KW - ERP - System KW - Machine Learning KW - durchgängig digitalisierter Produktionsprozess Y1 - 2019 UR - https://akwi.hswlu.ch/issue/view/376/431 SN - 2296-4592 IS - 10 SP - 46 EP - 53 PB - AKWI ER - TY - JOUR A1 - Prommesberger, Christian A1 - Langer, Christoph A1 - Ławrowski, Robert Damian A1 - Schreiner, Rupert T1 - Investigations on the long-term performance of gated p-type silicon tip arrays with reproducible and stable field emission behavior JF - Journal of Vacuum Science & Technology B N2 - The authors report on the fabrication and characterization of p-type Si tip arrays with an integrated gate electrode for applications as field emission electron sources. After the reactive ion etching of the emitters, the combined thermal dry and wet oxidation was used for both the sharpening of the emitters and for the realization of an enhanced insulation layer. Au was evaporated in a self-aligned process as gate electrode. Arrays of 16 Si tips were fabricated with tip heights of about 3 μm and tip radii of about 20 nm with integrated gate electrode concentrically positioned ≈2 μm below the tip apex. Integral measurements with an additional anode showed improved field emission properties with a reproducible and stable emission behavior. A fast activation of the tips, low onset voltages of about 30 V, and moderate field emission currents up to 0.55 μA were noticed. The field emission parameters were calculated using the Fowler–Nordheim characteristics. A pronounced saturation regime was observed, and current fluctuations of less than ±1% were investigated for 30 min. Long-term measurements were carried out for a period of more than 8 h. In the first 6 h of operation, the authors observed a drift of the emission current from 0.35 to 0.55 μA caused by an increased emission surface. Y1 - 2017 U6 - https://doi.org/10.1116/1.4972519 VL - 35 IS - 1 ER - TY - JOUR A1 - Breuer, Janis A1 - Bachmann, Michael A1 - Düsberg, Felix A1 - Pahlke, Andreas A1 - Edler, Simon A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Ławrowski, Robert Damian A1 - Schreiner, Rupert A1 - Serbun, Pavel A1 - Lützenkirchen-Hecht, Dirk T1 - Extraction of the current distribution out of saturated integral measurement data of p-type silicon field emitter arrays JF - Journal of Vacuum Science and Technology B N2 - At the moment, only complicated techniques are known for the determination of array properties of field emitter arrays such as the number of active tips, the current distribution, or the individual tip radii. In this work, a method for extracting these parameters from integral measurement data is presented. A model describing the characteristics of a single emitter, including the saturation as a function of the applied voltage and the emitter radius, is developed. It is shown that experimental data of field emitter arrays can be represented as the sum of these functions and the characteristic parameters can be fitted to field emission data of an array. Using this method, the values of the radii as well as the parameters of distribution models can be determined directly. Analysis of experimental data from p-type Si emitter arrays shows that only 1–2% of the tips contribute significantly. Y1 - 2018 U6 - https://doi.org/10.1116/1.5035189 VL - 36 IS - 5 PB - AIP Publishing ER - TY - JOUR A1 - Edler, Simon A1 - Bachmann, Michael A1 - Breuer, Janis A1 - Dams, Florian A1 - Düsberg, Felix A1 - Hofmann, Martin A1 - Jakšič, Jasna A1 - Pahlke, Andreas A1 - Langer, Christoph A1 - Ławrowski, Robert Damian A1 - Prommesberger, Christian A1 - Schreiner, Rupert T1 - Influence of adsorbates on the performance of a field emitter array in a high voltage triode setup JF - Journal of Applied Physics N2 - In the present work, black-silicon field emitter arrays (FEAs) are investigated regarding the influence of residual gas pressure on the characteristics and lifetime in the high voltage triode setup. Current-voltage-characteristics at different pressure levels are recorded and show a decreasing emission current with rising pressure. This decrease can be explained by an increase of the work function and charging of the emitter surface caused by adsorbates. The emission current can be restored to its initial value by heating of the FEA up to 110 °C during active emission. With this regeneration procedure, an extended lifetime from about 20 h to 440 h at a residual gas pressure of 10−5 mbar is achieved. Y1 - 2017 U6 - https://doi.org/10.1063/1.4987134 VL - 122 ER - TY - THES A1 - Zrenner, Louis T1 - Modellierung des gekoppelten thermischen und hydraulischen Verhaltens von ZFSV-Bettungen bei erdverlegten Höchstspannungsleitungen BT - Berechnung der thermo-hydraulischen Wechselwirkungen in Plaxis 2D anhand der Messergebnisse des DC CTL DBI Projekts N2 - Durch die dezentrale Energiegewinnung, welche aus dem Fokus auf regenerative Stromerzeugung resultiert, ist ein Ausbau des Übertragungsnetzes alternativlos – auch mit Hinblick auf den steigenden Strombedarf in den kommenden Jahrzehnten. Der Ausbau ist bereits beschlossene Sache, schreitet aber schleppend voran. Die Gründe hierfür sind jedoch nicht etwa Verzögerungen in der Bauausführung, sondern vor allem die Ablehnung innerhalb der Bevölkerung gegenüber dem Neubau von Stromtrassen. Jahrelange Planungs- und Genehmigungsphasen sowie regelmäßige Änderungen der Trassenverläufe sind die Folge. Die Bürgerbewegungen gegen den Netzausbau sind meist mit auf dem Einfluss auf das Landschaftsbild, der Strahlungsbelastung oder Lärmbelästigung begründet. Eine Erdverlegung würde hinsichtlich dieser Probleme (trotz kurzfristiger Mehrbelastung während der Bauphase) eine Alternative darstellen, weist jedoch baubedingte Problematiken wie den Abtransport der Verlustwärme auf. Bei einer klassischen Sandbettung hängt die Wärmeleitfähigkeit maßgeblich vom Wassergehalt des Sandes ab, welcher je nach Witterungslage und geologischen Gegebenheiten sehr stark schwankt. Als Folge muss die Trasse für den ungünstigsten Fall und damit unwirtschaftlich bemessen werden. Im Rahmen des Forschungsprojekts „DC-CTL DBI“ wurde eine gasisolierte HGÜ-Leitung (GIL) erdverlegt und einem Langzeitversuch unterzogen. Anstelle einer Sandbettung wurde jedoch ein zeitweise fließfähiger, selbstverdichtender Verfüllbaustoff (ZFSV) verwendet. Für den Einsatz als thermische Bettung bietet ein ZFSV mehrere Eigenschaften, welche eine klassische Sandbettung nicht bietet. So ist mit Hinblick auf die verschweißte Aluminium-Hülle der GIL kein Verdichtungsaufwand nötig, welcher bei aktueller Bauform zweifelsfrei in Schäden resultieren würde. Darüber hinaus weisen Flüssigböden durch den Bentonit-Gehalt eine höhere adsorbierende Oberfläche auf, wodurch der Anteil des Haftwassers im Boden zunimmt und die Wärmeleitfähigkeit der Bettung in ihrer Konstanz positiv beeinflusst wird. Im Zuge dieser Arbeit wurden die thermischen und hydraulischen Transportprozesse um die GIL mittels FEM in Plaxis2D untersucht und transient über den gesamten Messzeitraum (18 Monate) berechnet. Hierfür wurden die Materialparameter durch labortechnische Versuche ermittelt und die Messergebnisse einer verbauten Wetterstation als Randbedingungen (Niederschlag, Temperatur, Evapotranspiration) aufgebracht. Die Ergebnisse aus Plaxis2D wurden abschließend mit der im Feldversuch verbauten Sensorik verglichen. Es zeigte sich, dass sowohl die Boden- als auch die Leitertemperaturen nur um wenige Grad von den Messwerten der Sensorik abweichen. Anders als bei den etablierten analytischen Bemessungsrechnungen, welche stets auf Vereinfachungen basieren, können auch Effekte wie konvektiver Wärmetransport oder Austrocknung bei gleichzeitig höherer Genauigkeit der Ergebnisse untersucht werden. Um den Rechenaufwand gering zu halten, wurden lediglich die thermischen und hydraulischen Entwicklungen und Einflüsse des Bodens berücksichtigt. Es ist aber durchaus möglich, Verformungen und Kräfte in die Berechnung zu integrieren und so ein ganzheitliches Berechnungsmodell zu erstellen. KW - Geotechnik KW - ZFSV KW - Erdkabel KW - FEM KW - underground cables Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-17905 ER - TY - JOUR A1 - Lauer, Norina A1 - Giordano, Katharina A1 - Kreiter, Daniel A1 - Leusch, Vera A1 - Corsten, Sabine T1 - "Mach mal ’ne App" BT - Qualitätssicherung digitaler Entwicklungen am Beispiel der App BaSeTaLK JF - Forum Logopädie N2 - Die Entwicklung qualitativ hochwertiger Apps zur Gesundheitsversorgung erfordert einen aufwendigen Entwicklungsprozess, an den sich eine Evaluation der App-gestützten Maßnahme anschließen sollte, um Aussagen zur Wirksamkeit treffen und somit den App-Einsatz begründen zu können. In diesem Beitrag wird die nutzerzentrierte Entwicklung der App BaSeTaLK vorgestellt, mit der eine Tablet-gestützte Stimulation biographisch orientierter Gespräche bei älteren Menschen zur Verbesserung des psychischen Wohlbefindens ermöglicht werden soll. Nach erfolgreicher Evaluation könnten LogopädInnen als MultiplikatorInnen den Einsatz der App vermitteln. KW - App KW - Biografieforschung KW - Qualitätskontrolle KW - Senioren KW - Design Thinking Y1 - 2021 U6 - https://doi.org/10.2443/skv-s-2021-53020210304 VL - 35 IS - 3 SP - 20 EP - 27 PB - Schulz-Kirchner ER - TY - GEN ED - Rudolph, Clarissa ED - Reber, Anne ED - Dollsack, Sophia T1 - Geschlechtergerechtigkeit und MINT BT - Irritationen, Ambivalenzen und Widersprüche in Geschlechterdiskursen an Hochschulen KW - Hochschule KW - MINT-Fächer KW - Gleichstellung KW - Frauenförderung Y1 - 2022 SN - 978-3-8474-1674-6 U6 - https://doi.org/10.3224/84742519 PB - Verlag Barbara Budrich CY - Opladen ; Berlin ; Toronto ER - TY - JOUR A1 - Lührmann, Melanie A1 - Weiss, Matthias T1 - The Effect of Working Time and Labor Force Participation on Unemployment BT - A New Argument in an Old Debate JF - Economic Modelling N2 - This paper introduces a new argument into the theoretical literature on labor market effects of changes in working hours and labor force participation. We advance a general equilibrium model in which increased labor supply reduces unskilled unemployment via consumer demand: longer work hours and higher labor force participation imply higher incomes and less (leisure) time. In consequence, home production is reduced in favor of outsourcing domestic tasks to the market, shifting consumer demand toward unskill-intensive goods. Relative demand for unskilled labor rises and unemployment falls. Finally, we provide empirical support for the basic mechanisms of our model for Germany. KW - Working time reduction KW - Labor force participation KW - Low skill unemployment KW - Home production KW - Time use Y1 - 2010 U6 - https://doi.org/10.1016/j.econmod.2009.07.024 VL - 27 IS - 1 SP - 67 EP - 82 ER - TY - CHAP A1 - Börsch-Supan, Axel A1 - Düzgün, Ismail A1 - Weiss, Matthias ED - Börsch-Supan, Axel ED - Erlinghagen, Marcel ED - Hank, Karsten ED - Jürges, Hendrik ED - Wagner, Gert G. T1 - Altern und Produktivität BT - Eine neue Sichtweise T2 - Produktivität in alternden Gesellschaften KW - Alternde Bevölkerung KW - Arbeitsproduktivität Y1 - 2009 SP - 53 EP - 62 PB - Wissenschaftliche Verlagsgesellschaft mbH CY - Stuttgart ER - TY - CHAP A1 - Ilmakunnas, Pekka A1 - Skirbekk, Vegard A1 - van Ours, Jan A1 - Weiss, Matthias ED - Garibaldi, Pietro T1 - Ageing and Productivty T2 - Ageing, Health, and Productivity: The Economics of Increased Life Expectancy KW - Alter KW - Arbeitsproduktivität KW - Gesundheitsausgaben KW - Wirtschaftsentwicklung Y1 - 2009 SP - 135 EP - 219 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Weiss, Matthias T1 - Skill-Biased Technological Change BT - Is there Hope for the Unskilled? JF - Economics Letters N2 - This paper presents a model in which perpetual skill-biased technological change does not lead to ever-increasing wage inequality. The model is consistent with the increase in wage inequality in the 1980s and the subsequent stabilization in the 1990s. KW - Skill-biased technological change KW - Wage inequality KW - Factor substitution Y1 - 2008 U6 - https://doi.org/10.1016/j.econlet.2008.03.022 VL - 100 IS - 3 SP - 439 EP - 441 ER - TY - CHAP A1 - Börsch-Supan, Axel A1 - Düzgün, Ismail A1 - Weiss, Matthias ED - Prager, Jens U. ED - Schleiter (Hrsg.), André T1 - Sinkende Produktivität alternder Belegschaften? BT - Zum Stand der Forschung T2 - Länger leben, arbeiten und sich engagieren. Chancen werteschaffender Beschäftigung bis ins Alter Y1 - 2006 SN - 3892049130 SP - 85 EP - 102 PB - Bertelsmann Stiftung CY - Gütersloh ER - TY - JOUR A1 - Börsch-Supan, Axel A1 - Weiss, Matthias ED - Kruse, Andreas T1 - Erfahrungswissen in der Arbeitswelt JF - Potenziale im Altern. Chancen und Aufgaben für Individuum und Gesellschaft Y1 - 2010 SP - 221 EP - 234 PB - AKA CY - Heidelberg ER - TY - JOUR A1 - Weiss, Matthias ED - Kuhn, Michael ED - Ochsen, Carsten T1 - Absenteeism in Age-Diverse Work Teams JF - Labour Markets and Demographic Change N2 - Age-diverse work teams are being advocated as an important management tool to enhance performance and productively employ older workers. However, this advice is not founded on empirical evidence. There are very few studies that look at the relation between performance and age diversity of work teams. This lack of evidence is mainly due to a lack of available data. Information on performance and worker composition of a productive unit is available almost exclusively on the plant level in matched employer-employee data sets. But on the plant level/age heterogeneity of the workforce does not tell much about age diversity on the level where co-operation/teamwork takes place (work teams, departments, etc.). If all of the older workers work in the administration whereas all the young employees work in the production, the firm's workforce may be highly age-diverse, but work teams and departments are age-homogeneous. This problem notwithstanding, Grund and Westergård-Nielsen (2005) look at the relation between productivity and the standard deviation of workers’ age in a sample of 7,000 Danish firms. They find a hump-shaped relation. Y1 - 2009 U6 - https://doi.org/10.1007/978-3-531-91478-7_3 SP - 40 EP - 57 PB - VS Verlag CY - Wiesbaden ER - TY - JOUR A1 - Weiss, Matthias T1 - Erfahrung kompensiert nachlassende Fähigkeiten BT - Optimistische Befunde aus der Altersforschung JF - Personalführung Y1 - 2013 IS - 1 SP - 56 EP - 58 ER - TY - JOUR A1 - Sterner, Michael A1 - Bauer, Franz T1 - Power-to-X im Kontext der Energiewende und des Klimaschutzes in Deutschland JF - Chemie-Ingenieur-Technik N2 - Um den Einfluss verschiedener Power-to-X-Verfahren auf die Transformation des deutschen Energiesystems und das Erreichen der Klimaschutzziele zu überprüfen, wurde ein sektorübergreifendes Energiesystemmodel entwickelt. Die daraus gewonnenen Ergebnisse zeigen: Für eine erfolgreiche Energiewende ist der Einsatz von Power-to-X in Zukunft unverzichtbar. Vor allem in Bereichen und Sektoren, in denen hohe Energiedichten erforderlich und nur wenig andere Optionen zur Defossilisierung vorhanden sind, werden Power-to-X-Technologien zwingend notwendig. T2 - Power-to-X in Context of Energy Transition and Climate Change Mitigation in Germany KW - Power-to-Gas KW - Climate mitigation KW - Energy system KW - Modeling KW - Power-to-X KW - Klimaschutz KW - Energiewende Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-11669 SN - 0009-286X N1 - Corresponding author: Franz Bauer VL - 92 IS - 1-2 SP - 85 EP - 90 PB - Wiley ER - TY - JOUR A1 - Schubert, Martin J. W. A1 - Höfflinger, Bernd A1 - Schröder, D. A1 - Zingg, René P. T1 - 1D Modeling of SOI MOSFETs Using Distinct Quasi-Fermi Potentials JF - Microelectronic Engineering N2 - Distinct electron and hole quasi-Fermi potentials, øf,n and øf,p, are included into a one-dimensional SOI MOSFET model that accounts for finite inversion and depletion layer thicknesses. The inclusion of øf,n, øf,p in the nonlinear analytical model is demonstrated to describe phenomena like kink effect and the multistable-charge-controlled-memory effect (MCCM) in SOI MOSFETs. The calculation of øf,p(t) depends on the device history and generation/recombination rates. Y1 - 1991 U6 - https://doi.org/10.1016/0167-9317(91)90221-X VL - 15 IS - 1-4 SP - 237 EP - 240 ER - TY - CHAP A1 - Schubert, Martin J. W. T1 - Mixed Analog-Digital Signal Modeling Using Event-Driven VHDL T2 - X Brazilian Symposium on Integrated Circuit Design (SBCCI'97), August 25-27 1997, Porto Alegre, Brazil N2 - A method for solving networks containing generic analog components such as resistors, capacitors and inductors onan event driven time axis using digital VHDL is presented. The components are modeled as complex state machines communicating with their neighbors using INOUT type ports. The method takes advantage of simulation deltas to iterate without simulation-time consumption. A limited range of implicit equations can be solved this way. Y1 - 1997 UR - http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=50F6F0DA594FB90976CC1474581BC139?doi=10.1.1.508.3657&rep=rep1&type=pdf SP - 77 EP - 86 ER - TY - JOUR A1 - Schubert, Martin J. W. T1 - 70V-to-5V Differential CMOS Input Interface JF - IEE Electronic Letters Y1 - 1994 U6 - https://doi.org/10.1049/el:19940235 VL - 30 IS - 4 SP - 296 EP - 297 ER - TY - CHAP A1 - Declerq, Michel A1 - Schubert, Martin J. W. A1 - Clément, F. T1 - 5V-to-75V CMOS Output Interfaces T2 - Proceedings of the1993 IEEE International Solid-State Circuits Conference (ISSCC), Feb. 24-26 1993, San Francisco, CA, USA N2 - A family of CMOS low- to high-voltage output interface circuits based on a standard, unmodified low-voltage CMOS technology is described. Using only thin-oxide high-voltage (HV) devices with reduced V/sub GS/ (gate-to-source voltage) swing, it makes use of level-shift techniques to meet the constraints on the gate control signals. These static circuits permit the full output voltage swing of V/sub DDH/, while keeping the V/sub GS/ swing of the output devices within the safety limits, including during HV supply transients. Using a standard 2- mu m n-well CMOS technology, reliable, reproducible V/sub DS/ breakdown voltages as high as 120 V and 80 V have been obtained for HV-nMOS and HV-pMOS devices, respectively.< > Y1 - 1993 U6 - https://doi.org/10.1109/ISSCC.1993.280014 SP - 162 EP - 163 ER - TY - JOUR A1 - Schubert, Martin J. W. A1 - Höfflinger, Bernd A1 - Zingg, René P. T1 - An Analytical Model for Strongly Inverted and Accumulated Silicon Films JF - Solid-State Electronics N2 - An analytical model for the spatial distribution of potential, electric field and carrier densities is presented, assuming uniform doping density and constant quasi-Fermi potentials in the direction of modeling. Starting from the current relations a differential equation respecting two-dimensional effects is developed and solved approximately by decomposition in three regions with different preconditions: (a) flatband region, (b) constant spacecharge density and (c) strong inversion or accumulation. Inaccuracies arise mainly from violated preconditions at the interfaces between the different regions. Two-dimensional effects are respected in the analytical model of (b) only but they influence region (c) by means of boundary conditions at the interface of (b) and (c). The investigations of this paper are focused to region (c). This part of our model is identical to the model of Hauser and Littlejohn[1]. They integrated a simplified form of the semiconductor-Poisson equation twice but were restricted to one-dimensional applications and thermal equilibrium. Our derivation allows for large electric fields and current densities perpendicular to the direction of modeling. From analytical considerations confirmed by numerical experiments we suggest preference to the gradual channel condition, with x and y defined according to Fig. 1. This definition allows the potentials to vary significantly with respect to y. We found that this holds for the quasi-Fermi potentials also. Furthermore an empirical model for the maximum width of strong-inversion layers in uniformly doped silicon films is presented in eqn (46). Y1 - 1990 U6 - https://doi.org/10.1016/0038-1101(90)90136-3 VL - 33 IS - 12 SP - 1553 EP - 1567 PB - Elsevier ER - TY - CHAP A1 - Schubert, Martin J. W. T1 - Mixed Signal Modeling in VHDL by Distributed Local Iteration T2 - VHDL Form, Toledo, Spain, April 20-24, 1997 Y1 - 1997 ER - TY - CHAP A1 - Declerq, Michel A1 - Clément, F. A1 - Schubert, Martin J. W. A1 - Harb, Adnan A1 - Dutoit, Michel T1 - Design and Optimization of High-Voltage CMOS Devices Compatible wih a Standard 5V CMOS Technology T2 - Proceedings of IEEE Custom Integrated Circuits Conference, May 9-12 1993, San Diego, CA, USA N2 - High-voltage n- and p-MOSFETs fully compatible with a standard 5 V CMOS technology have been designed, optimized, and fabricated. No process changes are required. By modifying the logical equations generating one of the physical masks from the design masks, a p-type buffer region for the high-voltage p-MOS was easily implemented. This modification does not affect the low-voltage part of the circuits. These high-voltage devices have been used successfully as output drivers in semicustom arrays, and as building blocks for custom low- to high-voltage output interfaces. Aspects of reliability, device protection, and circuit design techniques are addressed. Y1 - 1993 SN - 0-7803-0826-3 U6 - https://doi.org/10.1109/CICC.1993.590766 SP - 24.6.1 EP - 24.6.4 ER - TY - THES A1 - Schubert, Martin J. W. T1 - Eindimensionale Modellierung von SOI MOSFETs Y1 - 1991 CY - Hamburg ER - TY - JOUR A1 - Schubert, Martin J. W. A1 - Höfflinger, Bernd A1 - Zingg, René P. T1 - A One-Dimensional Analytical Model for the Dual-Gate-Controlled Thin-Film SOI MOSFET JF - IEEE Electron Device Letters N2 - A one-dimensional analytical model for dual-gate-controlled SOI MOSFETs is presented and applied to a stacked p-channel MOSFET fabricated by epitaxial lateral overgrowth (ELO). The authors found and modeled a nonlinear dependence of front-gate threshold voltage on back-gate voltage if threshold is defined by a constant current instead of a constant silicon-surface potential. It is demonstrated by comparison of subthreshold slopes that surface potentials are not pinned to the onset of strong inversion or accumulation. Accurate one-dimensional modeling is a necessity for device characterization and a precondition for general SOI models for circuit simulation.< > Y1 - 1991 U6 - https://doi.org/10.1109/55.116927 VL - 12 IS - 9 SP - 489 EP - 491 ER - TY - CHAP A1 - Schubert, Martin J. W. A1 - Höfflinger, Bernd A1 - Zingg, René P. T1 - A New Analytical Charge Model for the Dual-Gate-Controlled Thin-Film SOI MOSFET T2 - Superlattices and Microstructures N2 - An analytical model for dual-gate-controlled SOI MOSFETs is presented, assuming uniformly doped p-silicon films. It is restricted to electron inversion layers and depletion regions, neglecting hole densities. It allows to account for the spatial description of electronic quantities in the silicon film. Due to the non-linearities of the semiconductor equations the model parameters must be extracted iteratively. Some applications are presented to demonstrate the usefulness of the model. Y1 - 1990 U6 - https://doi.org/10.1016/0749-6036(90)90218-V VL - 7 IS - 4 SP - 323 EP - 326 PB - Elsevier ER - TY - THES A1 - Spirkl, Florian T1 - Vergleichende rechnerische Untersuchungen zur Lastaufteilung und Setzungen von Stabilisierungssäulen mit Lasttransferschichten N2 - Die Erschließung von Neubauflächen, steigende Bauwerkslasten und strengere Anforderungen an Setzungen und Setzungsdifferenzen führen zu einem steigenden Bedarf an Tiefgründungsmaßnahmen. Eine relativ junge Entwicklung auf diesem Gebiet ist die Anwendung von Stabilisierungssäulen (StS) und pfahlähnlichen Tragelementen als Alternative zur konventionellen Pfahlgründung. Auf Grund der im Vergleich zum Pfahl geringeren Tragfähigkeit der StS werden diese zumeist als „Säulenwald“ angeordnet und die abzutragende Last über eine Lasttransferschicht (LTS) auf die einzelnen StS abgeleitet. Zusätzlich wird häufig eine oder mehrere Geogitterlagen eingebracht, was zur Erhöhung des Lastanteils der StS führt. Ein gängies Anwendungsbeispiel hierfür ist z.B. die Gründung eines Damms. Über die Lastaufteilung zwischen StS und anstehender Weichschicht wurden im Laufe der Jahre verschiedenste Theorien und Berechnungsansätze veröffentlicht. Zunächst wird eine Auswahl verschiedener geschlossener Berechnungsansätze für den 3-dimensionalen Fall vorgestellt und miteinander verglichen. Diesen ist gemein, dass für die Lastaufteilung lediglich die bodenmechanischen Eigenschaften der LTS und die geometrischen Parameter benötigt werden. Eine Berücksichtigung der anstehenden Weichschicht ist z.B. bei der iterativen Berechnung mittels Lasttransfermethode oder bei FE-Berechnungen möglich. Diese Ansätze werden, da durch die Berücksichtigung der Eigenschaften der Weichschicht weitere Freiheitsgrade entstehen, gesondert miteinander verglichen. Abschließend wird an Hand zweier Beispiele die Komplexität der Problemstellung „Ermittlung der Laustaufteilung zwischen StS und WS“ aufgezeigt. KW - Geotechnik KW - Stabilisierungssäule KW - Lasttransferschicht Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-15713 CY - Regensburg 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 - 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 -