@inproceedings{SchelsHerdlHausladenetal., author = {Schels, Andreas and Herdl, Florian and Hausladen, Matthias and Wohlfartsst{\"a}tter, Dominik and Bachmann, Michael and Edler, Simon and D{\"u}sberg, Felix and Pahlke, Andreas and Buchner, Philipp and Schreiner, Rupert and Hansch, Walter}, title = {Beta Factor Mapping of Individual Emitting Tips During Integral Operation of Field Emission Arrays}, series = {2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA}, booktitle = {2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA}, publisher = {IEEE}, isbn = {979-8-3503-0143-4}, doi = {10.1109/IVNC57695.2023.10188957}, pages = {224 -- 226}, abstract = {Emission uniformity mappings of field emitter arrays provide important insight into degradation mechanisms, but are often laborious, non-integral, costly, or not quantifiable. Here, a low-cost Raspberry Pi HQ camera is used as an extraction anode to quantify the emission distribution in field emitter arrays. A verification measurement using controlled SEM electron beams proves, that current-voltage characteristics of individual emission sites can be determined by combining the integral electrical data with the image data. The characteristics are used to quantify the field enhancement factors of an 30x30 silicon field emitter array during integral operation. Comparison of the field enhancement factor distributions before and after a one-hour constant current operation at 1 µA shows an increase from 50 actively emitting tips before to 156 after the measurement. It is shown, that the distribution of field enhancement factors shifts towards lower values, due to the increasing degradation for high field enhancement tips, especially above 1500.}, language = {en} } @inproceedings{HerdlKueddelsmannSchelsetal., author = {Herdl, Florian and Kueddelsmann, Maximillian J. and Schels, Andreas and Bachmann, Michael and Edler, Simon and Wohlfartsst{\"a}tter, Dominik and D{\"u}sberg, Felix and Prugger, Alexander and Dillig, Michael and Dams, Florian and Schreiner, Rupert and Coile{\´a}in, Cormac {\´O}. and Zimmermann, Stefan and Pahlke, Andreas and Duesberg, Georg S.}, title = {Characterization and Operation of Graphene-Oxide-Semiconductor Emitters at Atmospheric Pressure Levels}, series = {2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA}, booktitle = {2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA}, publisher = {IEEE}, isbn = {979-8-3503-0143-4}, doi = {10.1109/IVNC57695.2023.10188974}, pages = {14 -- 16}, abstract = {In recent years Graphene-Oxide-Semiconductor (GOS) electron emitters have attracted a lot of interest due to their outstanding durability in modest vacuum conditions. However, the performance at ambient pressure remains largely unexplored. In this study GOS-emitters are characterized in nitrogen and air at atmospheric pressure, and compared with their vacuum characteristics. For this purpose, lifetime and IV-characteristics measurements are shown. Furthermore, the GOS-emitter was operated as an ionization source for ion mobility spectrometry (IMS) at ambient conditions.}, language = {en} } @inproceedings{HausladenBuchnerSchelsetal., author = {Hausladen, Matthias and Buchner, Philipp and Schels, Andreas and Edler, Simon and Bachmann, Michael and Schreiner, Rupert}, title = {An Integrated Field Emission Electron Source on a Chip Fabricated by Laser-Micromachining and Mems Technology}, series = {2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA}, booktitle = {2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA}, publisher = {IEEE}, isbn = {979-8-3503-0143-4}, doi = {10.1109/IVNC57695.2023.10189001}, pages = {115 -- 116}, abstract = {A silicon field emission electron source consisting of a cathode and a grid electrode has been fabricated by laser micromachining. The cathode features 21×21 tips on an area of 4×4 mm 2 , With a self-aligning MEMS technology for the aperture grid, a high electron transmission (99 \%) was achieved. Onset voltages of 50…70 V were observed for an emission current of 1 nA. A stable emission current of 1 mA ± 1.3 \% at an extraction voltage of 250 V was observed during a 30-min operation.}, language = {en} } @inproceedings{BuchnerHausladenSchelsetal., author = {Buchner, Philipp and Hausladen, Matthias and Schels, Andreas and Herdl, Florian and Edler, Simon and Bachmann, Michael and Schreiner, Rupert}, title = {An Integrated Silicon Nanowire Field Emission Electron Source on a Chip with High Electron Transmission}, series = {2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA}, booktitle = {2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA}, publisher = {IEEE}, isbn = {979-8-3503-0143-4}, doi = {10.1109/IVNC57695.2023.10188878}, pages = {6 -- 8}, abstract = {Silicon nanowire field emission arrays (50 × 50 pillars) were fabricated on a silicon glass hybrid wafer. The glass acts both as the support for the whole structure and insulator between cathode and extraction grid. The extraction grid matches the emitter structures and is optically aligned and adhered to the emitter chip by a vacuum compatible epoxide adhesive. These chips exhibit an emission current of about 600 μA at an extraction voltage of 300 V. The electron transmission through the grid is above 80 \%. 58-hour longtime measurements were conducted showing low degradation of the emission current and high stability of electron transmission.}, language = {en} } @inproceedings{HausladenSchelsBuchneretal., author = {Hausladen, Matthias and Schels, Andreas and Buchner, Philipp and Bartl, Mathias and Asgharzade, Ali and Edler, Simon and Wohlfartsst{\"a}tter, Dominik and Bachmann, Michael and Schreiner, Rupert}, title = {Improved Method for Determining the Distribution of FEA Currents by Optical CMOS Sensors}, series = {37th International Vacuum Nanoelectronics Conference (IVNC), 15-19 July 2024, Brno, Czech Republic}, booktitle = {37th International Vacuum Nanoelectronics Conference (IVNC), 15-19 July 2024, Brno, Czech Republic}, publisher = {IEEE}, doi = {10.1109/IVNC63480.2024.10652543}, pages = {1 -- 2}, abstract = {CMOS image sensors are utilized to determine the time- and spatially-resolved distribution of the electron emission of silicon field emission arrays. During initial experiments, rather low field emission currents already visibly damaged the sensor surface, altering the system accuracy over the measurement time. Therefore, we coated the sensor surface with copper for protection. In contrast to the original insulating surface, the Cu coating provides a conductive surface for incident electrons and improves heat dissipation in addition. This prevents localized surface charges and surface damages which stabilize the system accuracy.}, language = {en} } @article{BachmannDuesbergPahlkeetal., author = {Bachmann, Michael and D{\"u}sberg, Felix and Pahlke, Andreas and Edler, Simon and Schels, Andreas and Herdl, Florian and Hausladen, Matthias and Buchner, Philipp and Schreiner, Rupert}, title = {The "LED-version" of the electron gun: An electron source for operation in ambient pressure environments based on silicon field emitter arrays}, series = {Vakuum in Forschung und Praxis}, volume = {35}, journal = {Vakuum in Forschung und Praxis}, number = {3}, publisher = {Wiley}, doi = {10.1002/vipr.202300801}, pages = {32 -- 37}, abstract = {We report on our progress to develop and optimize electron sources for practical applications. A simple fabrication process is introduced based on a wafer dicing saw and a wet chemical etch step without the need for a clean room. Due to the formation of crystal facets the samples show a homogeneous geometry throughout the array. Characterization techniques are developed to systematically compare various arrays. A very defined measurement procedure based on current controlled IV-sweeps as well as lifetime measurements at various currents is proposed. To investigate the current distribution in the array a commercial CMOS detector is used and shows the potential for in depth analysis of the arrays. Finally, a compact hermetically sealed housing is presented enabling electron generation in atmospheric pressure environments.}, language = {en} } @masterthesis{Zhong, type = {Bachelor Thesis}, author = {Zhong, Gantong}, title = {Calibration and Performance Evaluation of Contactless Optical Position Sensors Based on 3D Printed Optical Waveguides}, address = {Regensburg}, doi = {10.35096/othr/pub-8466}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-84668}, school = {Ostbayerische Technische Hochschule Regensburg}, pages = {35}, abstract = {This work presents the design, implementation, and performance evaluation of a positionsensing system based on a 3D printed optical waveguide. Building upon the conceptual foundation of D-shaped polymer optical fiber (POF) sensors [1], this study introduces a novel waveguide structure fabricated via multi-material fused filament fabrication (FFF) 3D printing. The waveguide incorporates a square-core geometry with integrated mechanical brackets and selective black cladding layer to enhance optical confinement and minimize boundary-induced nonlinearity. Three successive design iterations were developed and evaluated, with each version refined based on calibration results and structural observations. The final version demonstrated high fabrication stability and improved optical behavior, enabling consistent calibration across multiple samples. Using a center-corrected linear attenuation model, the position of a side-coupled LED was estimated from dual photodiode signals and compared with true light source position. The measurement results for five independently printed waveguides show mean absolute errors below 0.2 mm and standard deviations as low as 0.268 mm. The sensor response was found to be highly linear over the 5-55 mm sensing range, with worst-case errors bounded within ±1.7 mm. Compared with traditional D-shaped POF sensors, where performance is limited by manual polishing variability and nonuniform attenuation, the 3D-printed approach offers superior linearity, submillimeter accuracy, and batch-to-batch reproducibility. These findings prove the feasibility of 3D-printed optical waveguides in scalable and precise position sensing applications, marking a further step toward the batch fabrication and and potential industrialization of contactless optical position sensors. A conclusion of the research findings and suggestions for future improvements were provided at the end of this thesis, offering insights for the further development in this area.}, language = {en} } @article{HausladenSchelsBuchneretal., author = {Hausladen, Matthias and Schels, Andreas and Buchner, Philipp and Bartl, Mathias and Asgharzade, Ali and Edler, Simon and Wohlfartsst{\"a}tter, Dominik and Bachmann, Michael and Schreiner, Rupert}, title = {Measurement of field emission array current distributions by metal-coated CMOS image sensors}, series = {Journal of Vacuum Science \& Technology B}, volume = {42}, journal = {Journal of Vacuum Science \& Technology B}, number = {6}, publisher = {AIP Publishing}, doi = {10.1116/6.0004074}, abstract = {A CMOS image sensor is utilized to determine the time- and spatially resolved distribution of the total electron emission current of a silicon field emission array. The sensor measures electron emission without the need for phosphorus screens or scintillators as converters. However, in initial experiments, rather low field emission currents of several hundreds of nanoamperes per emitter already damaged the sensor surface, which altered the systems' signal response over the measurement time. In consequence, we coated the CMOS sensor surface with a Cu layer for surface protection. In contrast to the original insulating surface, Cu is an excellent current- and heat-conductor, which avoids lens charging by providing a conductive path for incident electrons and has an improved heat dissipation capability. Measurements using a segmented field emission cathode with four individually addressable tips demonstrate a consistent correlation between the emission current and the sensor signal of the metal-coated image sensor. Furthermore, the characterization of a field emission array showed that single tip emission currents of up to 12 μA per tip are measurable without discernible damage effects of the sensor's surface.}, language = {en} } @article{SchreinerWiedmannCoenningetal., author = {Schreiner, Rupert and Wiedmann, J. and Coenning, W. and Porsche, J. and Gentner, Jean-Louis and Berroth, Manfred and Scholz, Ferdinand and Schweizer, H.}, title = {Fabrication approach for antiphase narrow linewidth complex coupled 1.55 μm DFB lasers}, series = {Electronics Letters}, volume = {35}, journal = {Electronics Letters}, number = {2}, publisher = {The Institution of Engineering and Technology IET}, issn = {0013-5194}, doi = {10.1049/el:19990132}, pages = {146 -- 148}, abstract = {A new method for fabricating narrow linewidth antiphase complex coupled MQW DFB lasers by periodically etching the active layer and quartemary InGaAsP overgrowth is reported. The minimum linewidth for a 375 µm long ridge waveguide laser is only 250 kHz at an optical output power of 4 mW.}, language = {en} } @article{HausladenSchelsAsgharzadeetal., author = {Hausladen, Matthias and Schels, Andreas and Asgharzade, Ali and Buchner, Philipp and Bartl, Mathias and Wohlfartsst{\"a}tter, Dominik and Edler, Simon and Bachmann, Michael and Schreiner, Rupert}, title = {Investigation of Influencing Factors on the Measurement Signal of a CMOS Image Sensor for Measuring Field Emission Currents}, series = {Sensors}, volume = {25}, journal = {Sensors}, number = {5}, publisher = {MDPI}, doi = {10.3390/s25051529}, pages = {17}, language = {en} } @article{SchwarzPastoetterTranetal., author = {Schwarz, Tobias and Past{\"o}tter, Angelina and Tran, T. H. and Schlosser, Marc and Kaulen, Corinna and Lechner, Alfred and Slabon, A. and Kammler, Martin}, title = {Effect of temperature on the growth of Cupric and Cuprous Nanoparticles in a wet chemical synthesis}, series = {Materials Letters}, volume = {381}, journal = {Materials Letters}, publisher = {Springer Nature}, doi = {10.1016/j.matlet.2024.137672}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-79279}, abstract = {Cuprous oxide (Cu2O) and cupric oxide (CuO) particles were synthesized using a wet chemical surfactant free method at different synthesis temperatures from 25 °C to 60 °C. Morphology, size, and chemical composition of the prepared Cu2O particles were analyzed by FESEM, PXRD, and UV-vis. We discovered that the chemical composition of the Cu2O particles remained unaffected by the synthesis temperature. However, morphology and size of the particles showed a strong temperature dependency. This could be attributed to the temperature induced formation of CuO species from the copper hydroxide (Cu(OH)2) precursor which also functions as copper precursor for the Cu2O particle growth. The cupric oxide species was determined to be the main cause for the formation of micrometer sized particles, whereas with the Cu(OH)2 precursor species for the Cu2O particles nanocubes with smaller edge lengths as well as octahedrons were obtained.}, language = {en} } @inproceedings{ŁawrowskiLangerSchreineretal., author = {Ławrowski, Robert Damian and Langer, Christoph and Schreiner, Rupert and Sellmair, Josef}, title = {Nano Emitters on Silicon Pillar Structures generated by a Focused Electron Beam Induced Deposition}, series = {International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan}, booktitle = {International Vacuum Nanoelectronics Conference (IVNC), 31st, 2018, Kyoto, Japan}, publisher = {IEEE}, doi = {10.1109/IVNC.2018.8520059}, pages = {1-2}, abstract = {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.}, language = {en} } @inproceedings{BuchnerHausladenBartletal., author = {Buchner, Philipp and Hausladen, Matthias and Bartl, Mathias and Schreiner, Rupert}, title = {Elektronenquellen basierend auf Feldemission aus Silizium}, series = {Tagungsband zum 4. Symposium Elektronik und Systemintegration ESI: 17. April 2024, Hochschule Landshut}, booktitle = {Tagungsband zum 4. Symposium Elektronik und Systemintegration ESI: 17. April 2024, Hochschule Landshut}, publisher = {Hochschule f{\"u}r Angewandte Wissenschaften Landshut}, address = {Landshut}, isbn = {978-3-9818439-9-6}, doi = {10.57688/421}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:860-opus4-4212}, pages = {46 -- 53}, abstract = {Der Beitrag gibt einen {\"U}berblick {\"u}ber zwei typische Bauformen f{\"u}r Elektronenquellen auf der Basis von Feldemission aus Silizium. Des Weiteren wird eine typische Trioden-Beschaltung solcher Elektronenquellen f{\"u}r hohe Elektronentransmission vorgestellt und dabei auf ihre Leistungsf{\"a}higkeit eingegangen.}, language = {de} } @article{BresinskyFillenberg, author = {Bresinsky, Markus and Fillenberg, Barbara}, title = {Krisen, Katastrophen und Konflikte}, series = {Hebammen Wissen}, volume = {6}, journal = {Hebammen Wissen}, number = {4}, doi = {10.1007/s43877-025-1335-x}, pages = {24 -- 27}, abstract = {Hebammen als Akteurinnen im Bev{\"o}lkerungsschutz In Deutschland folgt der Bev{\"o}lkerungsschutz einer komplexen Struktur, die sich gr{\"o}ßtenteils auch auf das Rettungswesen st{\"u}tzt. Doch die wertvolle Ressource Hebamment{\"a}tigkeit wurde dabei bisher nicht mitgedacht.}, language = {de} } @inproceedings{BresinskyBrischar, author = {Bresinsky, Markus and Brischar, Jule}, title = {Between association and dissociation : the legitimacy politics of CIMIC experimentation}, publisher = {CCOE}, doi = {10.35096/othr/pub-8562}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-85627}, pages = {21}, abstract = {NATO's Concept Development and Experimentation (CD\&E) works well for discrete technologies but is ill-suited to civil-military cooperation (CIMIC), where the 'capability' at stake is an interorganisational relationship. Drawing on regime-complex theory and organisational sociology, this paper argues that willingness to engage in joint CIMIC capability development hinges on legitimacy rather than technical utility. A legitimacy-scale metaphor captures the trade-off: functional gains from collaboration load one side; identity risks, such as threats to neutrality, autonomy, or safety, load the other. Three ideal-type cases test the framework. In stabilisation missions, humanitarian neutrality is vital, the scale tips toward identity risk, and co-creation remains siloed. In sudden-onset disasters, shared life-saving objectives reduce identity costs, functional incentives dominate, and integrated trials flourish. Territorial- and collective-defence scenarios occupy the middle ground: acute threat perception opens selective, often low-profile windows for cooperation, yet unresolved legal and reputational questions still temper overt collaboration. The analysis yields five practical lessons. First, legitimacy must be treated as a primary design variable. Second, the optimal depth of cooperation is context specific. Third, legitimacy-sensitive 'safe-to-fail' spaces - wargames, living labs, tabletop exercises - lower entry barriers. Fourth, structured reflection on legitimacy exposes red lines early and refines future joint efforts. Fifth, incremental processes can build trust and gradually relax legitimacy constraints. Recognising legitimacy as both constraint and resource allows practitioners to design CIMIC co-creation - and eventual experimentation - that is technically sound, politically acceptable, and ethically sustainable.}, language = {en} } @masterthesis{Xu, type = {Bachelor Thesis}, author = {Xu, Zhiming}, title = {Electronic circuit design and implementation of a contactless optical position measurement device}, address = {Regensburg}, doi = {10.35096/othr/pub-8520}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-85201}, school = {Ostbayerische Technische Hochschule Regensburg}, pages = {49}, abstract = {This thesis presents the design and implementation of a low-cost, highprecision analog front-end for a non-contact optical displacement measurement system. While the principle of sensing based on D-shaped optical fibers is well-established, its practical replication faces challenges of poor consistency from manual polishing and high material costs. To address these issues, we employ 3D-printed polymer waveguides as the core sensing medium and design a dedicated signal conditioning circuit to accompany it. The core work of this thesis revolves around a dual-channel, two-stage amplifier analog front-end. The circuit converts weak, nanoampere-level (nA) photocurrents from the photodiodes into voltage signals. These signals are stable, linear, and suitable for the microcontroller (MCU) to process. The entire design follows this workflow: starting from theoretical calculations, the circuit's performance in frequency domain, time domain, and noise was verified through LTspice simulation. Subsequently, the design was realized in hardware via PCB implementation, including guard rings. The experimental results show that the performance of the fabricated circuit is consistent with simulation. When integrated with the 3D-printed waveguide, the complete system performed end-to-end calibration and decoding. Over a 50 mm measurement range, the system achieved a maximum absolute error of less than 0.81 mm and a root mean square error below 0.4 mm. This research validates the feasibility of a complete, low-cost, non-contact displacement measurement solution—from the sensing structure to the signal processing—suitable for small-scale use.}, language = {en} } @inproceedings{ShahabUllahShehzadetal., author = {Shahab, Muhammad and Ullah, Abdul Wahab Usman and Shehzad, Muhammad and Shah, Syed Bilal and Joyo, M. Kamran and Khan, Sheroz}, title = {Optimal distributed generation placement in radial distribution system using particle swarm optimization}, series = {2024 IEEE 9th International Conference on Engineering Technologies and Applied Sciences (ICETAS)}, booktitle = {2024 IEEE 9th International Conference on Engineering Technologies and Applied Sciences (ICETAS)}, publisher = {IEEE}, doi = {10.1109/ICETAS62372.2024.11120307}, pages = {7}, abstract = {This paper addresses losses of power in Radial Distribution Systems (RDS), which significantly affect voltage levels and operational costs. The main aim is to optimize the positioning and size of Distributed Generation (DG) units, including Photovoltaic (PV) cells, and Wind Turbines (WT), to analyze the effect of DG placement in reducing the losses in power and enhancing the voltage profiles in radial distribution system (IEEE 33 bus system). This research employs Particle Swarm Optimization (PSO), a robust algorithm well-suited for tackling non-linear optimization issues in order to identify the appropriate placement and size for DG units. A number of scenarios with varying numbers of DG units are simulated, indicating significant reductions in active as well as reactive power losses. Likewise, the consistency and reliability requirements of modern distribution systems are improved as the voltage profile is improved. The key findings demonstrate that optimal DG integration enhances system efficiency, contributes to operational cost savings, and improves grid stability. PSO was chosen for its ability to effectively balance computational effort while achieving high accuracy in minimizing the losses associated with power and enhancing voltage profiles. In contrast to traditional optimization techniques, PSO offers superior accuracy and efficiency in addressing the challenges of non-linear optimization in RDS.}, language = {en} } @article{DiachkovaNikolaevaGuertler, author = {Diachkova, Yana and Nikolaeva, Sofiya and Guertler, Katherine}, title = {Communication in International Humanitarian Relief: Profiling Ukrainian Boundary Spanners}, series = {Journal of Intercultural Communication}, volume = {25}, journal = {Journal of Intercultural Communication}, number = {1}, publisher = {ICR Publications}, issn = {1404-1634}, doi = {10.36923/jicc.v25i1.1019}, pages = {98 -- 106}, abstract = {Boundary spanning—the actions and roles individuals or organizations undertake to bridge differences and facilitate communication, collaboration, and understanding across diverse cultural, organizational, or geographical divisions—is an essential element of international cooperation. Set against the backdrop of the Russia-Ukraine war, The purpose of this study is to explore the type of boundary spanning in this uncertain context, the linguistic characteristics of boundary spanners, the necessary skills and competencies required to navigate the complex socio-political landscape, and the role of boundary spanners in humanitarian assistance. This study employs a qualitative research approach, using semi-structured interviews with informants actively engaged in relief efforts and cross-cultural collaboration. The findings emphasized the significance of English as the primary language of communication, the importance of cultural sensitivity and awareness, and the need for intercultural competence in effective boundary spanning. The study concludes with insights from the ongoing Ukrainian experience of bridging geodemographic boundaries and the role of boundary spanners in this process, highlighting key aspects of boundary spanning. Overall, the study contributes to the theoretical background of boundary spanning and enhances the understanding of how linguistic and cultural boundary spanning can drive positive change and improve outcomes in humanitarian aid. The implications of this study suggest that underscore the critical need for collaboration with experienced boundary spanners in educational settings.}, language = {en} } @article{EilerWeberGerlesbergeretal., author = {Eiler, Julian and Weber, Stefan and Gerlesberger, Peter and Pl{\"o}chinger, Heinz and Schreiner, Rupert}, title = {Active heat-loss compensated miniaturized pirani sensor chip}, series = {IEEE Sensors Letters}, volume = {9}, journal = {IEEE Sensors Letters}, number = {10}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2475-1472}, doi = {10.1109/LSENS.2025.3605747}, pages = {4}, abstract = {Due to the limited measuring range of commercial Pirani sensors in lower pressure regimes, attempts are being made to extend the measuring range of the sensors. Our approach to extend the measuring range toward lower pressures is a micro-electromechanical systems (MEMS) Pirani sensor with active heat compensation on the suspensions. The sensor element has the shape of a microhotplate and consists of a nickel heating meander embedded in two silicon nitride layers. The whole structure is built on a silicon wafer. The sensor element is suspended on all four corners of the substrate. On each of the suspensions, there is an additional heating structure that minimizes the heat flux from the hot sensor element toward the substrate. The sensor is driven at a constant temperature through a self-balancing Wheatstone bridge. A constant voltage is applied to the heating structures on the suspensions. It has been demonstrated that with these additional heaters, the sensitivity of the sensor can be increased in the high-vacuum regime. This enables reliable vacuum measurements down to 10-6 mbar.}, language = {en} } @misc{EilerWeberGerlesbergeretal., author = {Eiler, Julian and Weber, Stefan and Gerlesberger, Peter and Pl{\"o}chinger, Heinz and Schreiner, Rupert}, title = {Miniaturized Pirani vacuum sensor with active heat-loss compensation}, series = {Verhandlungen der Deutschen Physikalischen Gesellschaft e.V. (DPG), Regensburg, 16. - 21. M{\"a}rz 2025}, journal = {Verhandlungen der Deutschen Physikalischen Gesellschaft e.V. (DPG), Regensburg, 16. - 21. M{\"a}rz 2025}, publisher = {Deutsche Physikalische Gesellschaft e.V.}, issn = {2751-0522}, abstract = {Pirani sensors measure the thermal conductivity of the residual gas in a vacuum by creating a thermal gradient between a heated sensor element and a heat sink. The heat flux from the sensor element to the heat sink over the residual gas is a measure of the vacuum and can be determined by the electrical power applied. In addition to the heat flux over the gas, there are further energy losses from the heating structure due to radiation and parasitic heat fluxes via the suspensions of the sensor element. These losses reduce the sensitivity of the sensor. For this reason, a Micro-Pirani sensor in the shape of a microhotplate was developed that actively compensates the heat flux via the suspensions. This was achieved by placing additional heating structures on the suspensions, which interrupt the heat flow from the sensor element via the suspensions during operation. This active compensation improves the sensitivity at low pressures, enabling vacuum measurements from atmospheric pressure down to 10e-6 mbar.}, language = {en} } @inproceedings{EilerBerndtSchreiner, author = {Eiler, Julian and Berndt, Dominik and Schreiner, Rupert}, title = {Miniaturisierter Wasserstoffsensor basierend auf der 3-Omega Methode}, series = {Tagungsband zum 4. Symposium Elektronik und Systemintegration ESI: 17. April 2024, Hochschule Landshut}, booktitle = {Tagungsband zum 4. Symposium Elektronik und Systemintegration ESI: 17. April 2024, Hochschule Landshut}, publisher = {Hochschule f{\"u}r Angewandte Wissenschaften Landshut}, address = {Landshut}, isbn = {978-3-9818439-9-6}, doi = {10.57688/420}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:860-opus4-4205}, pages = {38 -- 45}, abstract = {Die Arbeit stellt einen thermischen Wasserstoffsensor auf Siliziumbasis vor, der mit der 3-Omega Messmethode betrieben wird. Durch das dynamische Messverfahren, die große Sensoroberfl{\"a}che bei gleichzeitig geringer thermischer Masse und der Materialkombination wird eine Aufl{\"o}sungsgrenze von 55 ppm Wasserstoff in Stickstoff erreicht.}, language = {de} } @inproceedings{BauerVitzthumeckerBierletal., author = {Bauer, Lukas and Vitzthumecker, Thomas and Bierl, Rudolf and Ehrnsperger, Matthias}, title = {Machine-learning-based detection and severity estimation of drought stress in plants using hyperspectral imaging data}, series = {Remote Sensing for Agriculture, Ecosystems, and Hydrology XXVII}, booktitle = {Remote Sensing for Agriculture, Ecosystems, and Hydrology XXVII}, publisher = {SPIE}, doi = {10.1117/12.3072011}, pages = {7}, abstract = {Growing food demand due to population growth, coupled with increasingly frequent and severe droughts caused by climate change make water increasingly scarce. To address this, accurate assessment of plant water demand is essential for precise drought treatment and water conservation. Hyperspectral imaging (HSI) captures hypercubes, a combination of spectral and spatial data and offers promising capabilities for detection of plant stresses. However, most reported approaches only use selected spectral bands or indices, neglecting the full hypercube information. This is assumed to limit the detection accuracy. To overcome these limitations, we aim to develop a measurement pipeline to generate a comprehensive dataset comprising hypercubes of plants under varying drought stress levels along with selected physiological, environmental, and illumination data. This dataset will be used to train suitable data-driven models that enable improved drought stress detection as well as the non-invasive determination of physiological parameters based on HSI data.}, language = {en} } @inproceedings{Ehrnsperger, author = {Ehrnsperger, Matthias G.}, title = {Enhancing object recognition through camera-radar fusion and micro-doppler signature integration}, series = {Emerging Technologies and Materials for Security and Defence 2025}, booktitle = {Emerging Technologies and Materials for Security and Defence 2025}, publisher = {SPIE}, doi = {10.1117/12.3071682}, pages = {5}, abstract = {Object recognition systems based on visual sensors often struggle in degraded environmental conditions such as fog, rain, darkness, or occlusion. Radar, in contrast, offers robust detection capabilities under such conditions but lacks the spatial resolution of optical sensors. This paper presents an ongoing research effort towards a multimodal sensor fusion framework that integrates camera data with radar signals, specifically exploiting micro-Doppler (μD) signatures, with the aim of improving object recognition robustness. The proposed setup uses an Intel RealSense Depth Camera D455 and an Infineon BGT60TR13C radar sensor, deployed on a low-power embedded platform with STM32 microcontrollers. The signal processing pipeline, currently under development, combines time-frequency radar analysis with convolutional neural network-based visual feature extraction for real-time edge AI inference. We describe the system design, preliminary data acquisition setup, and planned evaluation strategy.}, language = {en} } @inproceedings{Ehrnsperger, author = {Ehrnsperger, Matthias G.}, title = {Multimodal sensor fusion for resilient perception: combining radar and imaging for all-weather object tracking}, series = {Artificial Intelligence and Image and Signal Processing for Remote Sensing XXXI}, booktitle = {Artificial Intelligence and Image and Signal Processing for Remote Sensing XXXI}, publisher = {SPIE}, doi = {10.1117/12.3071683}, pages = {5}, abstract = {This work presents the concept and initial qualitative observations of a multimodal perception system that fuses radar, lidar, and camera data to improve object detection and tracking under adverse environmental conditions. The approach focuses on building weather-impact models for each sensor modality—quantifying performance degradation effects such as color shifts and contrast loss in cameras, range reduction and spurious returns in lidar, and resolution limitations in radar. These models will later inform adaptive sensor fusion strategies deployed on embedded edge-AI hardware, using an Infineon BGT60TR13C FMCW radar, Intel RealSense D455 depth camera, and low-power processors. Preliminary visual inspection of collected datasets indicates that combining complementary sensing modalities can maintain detection continuity under conditions where single modalities fail. Future work will quantitatively evaluate these effects and demonstrate weather-adaptive perception on the embedded platform.}, language = {en} } @techreport{PfingstenBredehorstLeinweberetal., type = {Working Paper}, author = {Pfingsten, Andrea and Bredehorst, Maren and Leinweber, Juliane and Richter, Robert and Vogel, Barbara}, title = {HVG-Positionspapier f{\"u}r die Therapiewissenschaften : Fachkommission Forschung im Hochschulverbunde Gesundheitsfachberufe (HVG)}, edition = {Version 1 (Stand 08.04.2024)}, organization = {Fachkommission Forschung im Hochschulverbund Gesundheitsfachberufe (HVG) e.V.}, doi = {10.5281/zenodo.14495900}, pages = {6}, abstract = {Zeitgem{\"a}ße Therapie ist effektiv, effizient, patient*innen- und teilhabeorientiert. Ergotherapie, Logop{\"a}die/Sprachtherapie und Physiotherapie (im Folgenden kurz: ELP) sind gesellschaftlich relevant und essenzieller Bestandteil einer nachhaltigen Gesundheitsversorgung. Therapiewissenschaften evaluieren, verbessern und erweitern M{\"o}glichkeiten der Pr{\"a}vention und Behandlung von Krankheiten sowie der Beratung und Begleitung von Menschen in gesundheitlicher Hinsicht. Wer, wenn nicht die Therapeut*innen, stellt Forschungsfragen und verfolgt Forschungsinteressen, durch die forschungsbasiertes Wissen zu Therapie entsteht? Dieses Positionspapier der Fachkommission Forschung im HVG wurde entwickelt als Referenz zur Forschungslandschaft der ELP. Es ist als Argumentationshilfe gedacht, um die Voraussetzungen f{\"u}r die Therapiewissenschaften zu verbessern.}, subject = {Allied Health}, language = {de} } @article{PierobonSharshenova, author = {Pierobon, Chiara and Sharshenova, Aijan}, title = {German and Russian Public Diplomacy Efforts in Kyrgyzstan: A Comparative Study of Norm Entrepreneurship}, series = {Europe-Asia Studies}, volume = {75}, journal = {Europe-Asia Studies}, number = {8}, publisher = {Taylor \& Francis}, doi = {10.1080/09668136.2023.2213871}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-87380}, pages = {1384 -- 1407}, abstract = {This article explores Russian and German public diplomacy efforts in Central Asia through the example of Kyrgyzstan. Due to a difficult economic and socio-political situation, Kyrgyzstan remains open to externally funded programmes and projects, including initiatives funded by foreign governments, and thus offers a unique environment for the study of public diplomacy. The article looks at transnational public diplomacy actors such as German political foundations and Russian-sponsored organisations active in the country. Overall, the article offers interesting insights into the nature and substance of the soft power policies pursued by Germany and Russia that are relevant for Kyrgyzstan and beyond.}, language = {en} } @article{Pierobon, author = {Pierobon, Chiara}, title = {European Union, civil society and local ownership in Kyrgyzstan: analysing patterns of adaptation, reinterpretation and contestation in the prevention of violent extremism (PVE)}, series = {Central Asian Survey}, volume = {41}, journal = {Central Asian Survey}, number = {4}, publisher = {Taylor \& Francis}, doi = {10.1080/02634937.2021.1905608}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-87378}, pages = {752 -- 769}, abstract = {In the last decade, a growing body of literature has investigated the promotion of good governance, rule of law, democracy and human rights in Central Asia through funding from the European Union (EU). Most of this research has taken an EU-centric approach and is concerned with the supply side of external democratization. As a result, little is known about how EU projects are implemented on the ground and what EU-funded civil society organizations consider to be their priorities. This article investigates the agency of such organizations in Kyrgyzstan by focusing on their contribution to one particular EU instrument: the Instrument contributing to Stability and Peace (IcSP), and its programme: Strengthening Resilience to Violence and Extremism (STRIVE). The findings offer new insights into the processes of adaptation, reinterpretation and contestation through which EU-funded organizations exercise ownership while engaging in the prevention of violent extremism (PVE).}, language = {en} } @article{Pierobon, author = {Pierobon, Chiara}, title = {EU's support to civil society in Kazakhstan: A pilot evaluation of the social capital generated}, series = {Evaluation}, volume = {25}, journal = {Evaluation}, number = {2}, publisher = {Sage}, doi = {10.1177/1356389018796023}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-87394}, pages = {207 -- 223}, abstract = {In the last decade, several studies have been devoted to the analysis of the EU's support to civil society abroad, but only recently has scholarly attention turned to Central Asia. Most of the research in this field has adopted a macro-level perspective, concerned with the supply side of external democratization, and has examined external assistance to civil society in terms of democratization ideal types and typologies. The main contribution of this study consists of a meso-level analysis of the outcomes of the EU's support to civil society in terms of production of social capital, conceived as the raw material of civil society itself. More precisely, the article evaluates the first wave of grants awarded to civil society organizations in Kazakhstan as part of two EU funding schemes—the European Instrument for Democracy and Human Rights and the Non-State Actors and Local Authorities in Development. The article sheds new light on the use of social capital and its two dimensions-structural and cognitive-as heuristic tools for evaluating civil society support programs.}, language = {en} } @book{Kriza, author = {Kriza, Thomas}, title = {Ethische Fragen der Digitalisierung und ihre Thematisierung in Forschung und Lehre an Hochschulen}, series = {Interdisziplinarit{\"a}t in der Hochschullehre}, journal = {Interdisziplinarit{\"a}t in der Hochschullehre}, editor = {Lerch, Sebastian}, publisher = {wbv Publikation}, address = {Bielefeld}, isbn = {9783763974610}, doi = {10.3278/9783763974610}, pages = {45 -- 58}, abstract = {Die Digitalisierung als fortschreitende Durchdringung aller Lebensbereiche durch Informationstechnik geht mit gesellschaftlichen Transformationsprozessen und weitreichenden ethischen Fragen einher. Diese Fragen haben einen transdisziplin{\"a}ren Charakter in dem Sinne, dass sie sich nur durch ein {\"U}berschreiten von fachlichen Perspektiven einzelner wissenschaftlicher Disziplinen und durch eine ganzheitliche Bezugnahme auf gesellschaftliche Auswirkungen angemessen adressieren lassen. Anhand der technischen M{\"o}glichkeiten von Big Data Analytics l{\"a}sst sich aufzeigen, wie disziplin{\"u}bergreifende wissenschaftliche Forschungen zu technischen Anwendungen f{\"u}hren k{\"o}nnen, die gewichtige, gesellschaftlich relevante Fragen nach ihrer ethischen Vertretbarkeit aufwerfen. Diese k{\"o}nnen in letzter Konsequenz auch ethische Grundprinzipien und Auffassungen des Menschseins ins Wanken bringen. Besonders pr{\"a}gnant l{\"a}sst sich dies mit den Studien des Big-Data-Forschers Michal Kosinski und seines Forscherkreises sowie den daraus resultierenden Anwendungen von Unternehmen wie Cambridge Analytica vor Augen f{\"u}hren: Die Analyse von großen Mengen digitaler pers{\"o}nlicher Daten er{\"o}ffnet umfassende M{\"o}glichkeiten zur Verhaltensbeeinflussung und stellt dabei sehr weitreichend auch ethische Grundwerte wie Privatheit in Frage. Universit{\"a}ten und Hochschulen sind aufgefordert, durch transdisziplin{\"a}re Lehre und Forschung die ethischen Fragen der Digitalisierung als bestimmende Themen der Gegenwart direkt zu adressieren.}, language = {de} } @misc{Vokkethur, type = {Master Thesis}, author = {Vokkethur, Rachana}, title = {Design, simulation, fabrication, measurement, and analysis of 3D-printed radio frequency conductive structures}, address = {Regensburg}, doi = {10.35096/othr/pub-8780}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-87809}, school = {Ostbayerische Technische Hochschule Regensburg}, pages = {iv, 65}, abstract = {Additive manufacturing has emerged as a disruptive technology in the field of electronics, offering new possibilities for the fabrication of complex, lightweight, and customizable components. Conventional PCB manufacturing relies on multi-step processes and is limited to planar geometries, making it less suitable for rapid prototyping or integration into non-standard surfaces. In contrast, Fused Deposition Modelling (FDM) provides a cost-effective and accessible approach to directly fabricate functional electronic structures by combining conductive and dielectric materials within a single printing process. This thesis examines the design, simulation, fabrication, measurement and analysis of 3D-printed conductive transmission lines utilising FDM technology. A conductive filament and a dielectric filament are employed to realise fully integrated microstrip and coaxial structures. Electromagnetic simulations are performed to optimise the geometry for RF performance, and the printed prototypes are experimentally characterised using vector network analyser measurements. The analysis focuses on the transmission coefficients and the reflection coefficients, providing insights into impedance matching, insertion loss, and frequency-dependent behaviour. These findings confirm that FDM-based additive manufacturing can produce functional RF structures with reliable performance, despite material and fabrication limitations. The work demonstrates the potential of 3D printing as a flexible and low-cost method for prototyping radio frequency components, highlighting future directions that include improved material characterisation, connector integration, and the design of more advanced components, such as filters and antennas.}, language = {en} } @misc{KrysztofBaranowskiZychlaetal., author = {Krysztof, Michal and Baranowski, Kamil and Zychla, Michal and Hausladen, Matthias and Schreiner, Rupert and Kn{\´a}pek, Aleksandr}, title = {MP61 - Detection of Electron Beam in Atmospheric Pressure Using CMOS Image Sensor}, series = {EUROSENSORS XXXVII ; 07.09.2025 - 10.09.2025 ; Wroclaw ; Poster I}, journal = {EUROSENSORS XXXVII ; 07.09.2025 - 10.09.2025 ; Wroclaw ; Poster I}, publisher = {AMA}, doi = {10.5162/EUROSENSORS2025/MP61}, pages = {325 -- 326}, abstract = {In the article, a new detection system that enables observation of the electron beam signal passing through a gas layer at atmospheric pressure is presented. An experimental setup consisting of an elec-tron gun (electron emitter, extraction, and focus electrodes), silicon nitride membrane, and a CMOS image sensor is described, as well as first image of the electron beam spot after passing through 400 µm of air at atmospheric pressure is presented.}, language = {en} } @inproceedings{SadequeAhmmedHossainetal., author = {Sadeque, Md. Golam and Ahmmed, Tanvir and Hossain, Md. Aowal and Rahman, Md. Naimur and Sarker, Md Tanjil and Ramasamy, Gobbi}, title = {A Novel CWT-CNN Framework for Driver Fatigue Detection from EEG Signals}, series = {2025 Multimedia University Engineering Conference (MECON), 21-23 July 2025, Cyberjaya, Malaysia}, booktitle = {2025 Multimedia University Engineering Conference (MECON), 21-23 July 2025, Cyberjaya, Malaysia}, publisher = {IEEE}, isbn = {979-8-3315-5549-8}, doi = {10.1109/MECON67253.2025.11277149}, pages = {6}, abstract = {Fatigued driving has been a significant contributor to traffic accidents globally, posing serious threats to both human life and economic stability. Machine learning techniques based on electroencephalography (EEG) are showing promise for detecting driver fatigue, excelling other physiological modalities in this regard. However, it requires a lot of exertion, demands domain knowledge, and may not generalize effectively across different datasets to manually extract features from EEG signals. Therefore, investigating innovative deep-learning architectures that can effectively extract discriminative characteristics from unprocessed EEG data is necessary. This paper proposes a novel framework for driver fatigue detection from EEG signals using Continuous Wavelet Transform (CWT) and Convolutional Neural Networks (CNN). Rather than depending on hand-crafted feature extraction, we use CWT to convert EEG data into time-frequency spectrum pictures. After concatenating these spectral images from every channel, a CNN is fed to learn discriminative features for driver normal and fatigued states automatically. An average classification accuracy of 98.3\% is obtained by evaluating the proposed CWT-CNN system on a publicly available EEG dataset comprising recordings from twelve subjects. The results obtained indicate that the CWT-CNN framework has enormous potential to create strong driver fatigue detection systems, thereby enhancing road safety.}, language = {en} } @unpublished{FischerHirschReitmeieretal., author = {Fischer, Johannes and Hirsch, Thomas and Reitmeier, Torsten and Bierl, Rudolf}, title = {Real-time hardware-based processing of high-precision detector signals for surface plasmon resonance spectroscopy}, doi = {10.2139/ssrn.5971170}, pages = {16}, abstract = {Surface plasmon resonance (SPR) is limited by small-signal detectability and drift when subtraction occurs in software after digitization. We introduce an SPR detector that performs on-detector amplification and analog differential readout, eliminating moving parts and software-heavy correction. The hardware-native subtraction boosts the usable ADC range and suppresses illumination and environmental noise. In fixed-angle refractive-index steps (NaCl), the platform resolves Δn_min ≈ 1.8 × 10⁻⁷ RIU compared to 4.6-7.2 × 10⁻⁶ RIU on a commercial comparator and improves small-signal SNR by up to ∼5,000-fold, while remaining competitive at high signal levels. In a model IgG-BSA assay, the detector's low noise floor clarifies early binding and equilibrium transitions. By generating inherently clean raw signals, this hardware-native approach dramatically enhances sensitivity and long-term stability for label-free biosensing and inline process analytics while rendering AI-based or complex post-processing entirely unnecessary. The concept generalizes across platforms and opens a compact route to robust, high-fidelity SPR in complex environments, with a clear path toward multi-wavelength and arrayed detectors for high-throughput chemical monitoring.}, language = {en} } @inproceedings{BartlHausladenAsgharzadeetal., author = {Bartl, Mathias and Hausladen, Matthias and Asgharzade, Ali and Buchner, Philipp and Krysztof, Michal and Kn{\´a}pek, Alexandr and Bachmann, Michael and Schreiner, Rupert}, title = {Experimental method for investigation of the emission pattern characteristics of individual field emission tips using a CMOS image sensor}, series = {38th International Vacuum Nanoelectronics Conference (IVNC)}, booktitle = {38th International Vacuum Nanoelectronics Conference (IVNC)}, publisher = {IEEE}, doi = {10.1109/IVNC65669.2025.11121040}, pages = {2}, abstract = {The emission pattern characteristics of individual silicon field emission tips were investigated using a CMOS image sensor. The quality of the image was improved by spatial and temporal averaging, so that individual emission centers could be identified and their temporal changes investigated. By mapping the emission current onto the image, the distribution of the current density on the image sensor could be calculated.}, language = {en} } @inproceedings{JannsenEhrnsperger, author = {Jannsen, Kai and Ehrnsperger, Matthias}, title = {Edge-efficient convolutional neural network for real-time doppler radar gesture recognition}, series = {2025 IEEE Radar Conference (RadarConf25), 4.-9. Oktober 2025, Krakow}, booktitle = {2025 IEEE Radar Conference (RadarConf25), 4.-9. Oktober 2025, Krakow}, publisher = {IEEE}, isbn = {979-8-3315-4433-1}, doi = {10.1109/RadarConf2559087.2025.11205096}, pages = {877 -- 881}, abstract = {Embedded gesture recognition using radar sensors enables intuitive and robust human-machine interfaces, which is appealing for automotive applications such as trunk opening via foot gesture. Designing a radar-based classifier that runs ondevice (edge) under strict resource constraints poses several challenges. The system must achieve real-time inference (e.g. under 200 ms) on a microcontroller unit (MCU), while maintaining high accuracy, and minimize false detections. This paper focuses on a binary classification task, while distinguishing a valid trunkopening "kick" gesture from other motions. Firstly, we evaluate classical machine learning (cML) models (Random Forests or support vector machines (SVMs)) for baseline performance, however they face difficulties with higher false positive rates and do not meet real time criteria. We then employ Convolutional Neural Networks (CNNs) and apply neural architecture search (NAS) to discover a compact CNN tailored for a 60 GHz Doppler radar dataset of 50 subjects, each with 10 leg gestures. By constraining network depth, filter sizes, and hyperparameters, NAS yields a small but accurate "edge" CNN that fits within the limited memory of a STM32 Nucleo F446RE microcontroller. The final model achieves 95.1 \% accuracy on the binary classification task with 96.6 \% precision and 2.17 \% false positive rate (FPR), and requires only 167.5 ms to run inference on the MCU.}, language = {en} } @inproceedings{BaranowskiZychlaKrysztofetal., author = {Baranowski, Kamil and Zychla, Michał and Krysztof, Michał and Ż{\´o}łtowski, Michał and Hausladen, Matthias and Schreiner, Rupert and Kn{\´a}pek, Aleksandr}, title = {Experimenal method for studying electron beams in gaseous environments using a CMOS image sensor}, series = {38th International Vacuum Nanoelectronics Conference (IVNC)}, booktitle = {38th International Vacuum Nanoelectronics Conference (IVNC)}, publisher = {IEEE}, isbn = {979-8-3315-3705-0}, doi = {10.1109/IVNC65669.2025.11120851}, pages = {2}, abstract = {Detecting and analyzing electron beams in atmospheric conditions remains a significant challenge due to scattering and absorption of electrons by gas molecules. In this work, a novel approach using a CMOS image sensor for real-time electron beam detection after its transmission through air is presented. The setup enables visualization of beam divergence, emission profiles, and dynamic behavior under atmospheric pressure. Presented results demonstrate the potential of CMOS image sensor for electron beam analysis in gaseous environment.}, language = {en} } @inproceedings{AllahamBurdaKnapeketal., author = {Allaham, Mohammad M. and Burda, Daniel and Kn{\´a}pek, Alexandr and Krysztof, Michał and Baranowski, Kamil and Hausladen, Matthias and Schreiner, Rupert}, title = {Testing the performance of tungsten-graphite cathodes as MEMS Electron microscope electron source}, series = {38th International Vacuum Nanoelectronics Conference (IVNC)}, booktitle = {38th International Vacuum Nanoelectronics Conference (IVNC)}, publisher = {IEEE}, doi = {10.1109/IVNC65669.2025.11121041}, pages = {2}, abstract = {This work presents preliminary results of the performance testing of exfoliated graphene layers deposited on the nanotip of a tungsten field emission cathode. The obtained tungsten-graphite cathodes were then operated in a 3D-printed MEMS electron microscope testing model for later applications. The results were promising, where a maximum emission current of 50.2 μA was obtained with an extraction voltage of 1 kV and anode voltage of 3 kV.}, language = {en} } @article{WolfgrammAbbSampetal., author = {Wolfgramm, Alex and Abb, Valerius and Samp, Artur and Samp, Rafal and Hoffmann, Jens Christoph and M{\"u}ller, Rainer and Kammler, Martin}, title = {Structural and functional evolution of HKUST-1 nanoparticles induced by ball milling}, series = {Next Materials}, volume = {10}, journal = {Next Materials}, publisher = {Elsevier}, doi = {10.1016/j.nxmate.2025.101544}, pages = {7}, abstract = {In this study, the effect of post-synthetic ball milling on the structural and functional properties of as-synthesized nanoparticles of the copper-based metal-organic framework (MOF) HKUST-1 was investigated for the first time. Nanoparticles were synthesized using sodium formate as a capping agent. The crystalline particles were subjected to a controlled ball milling process, which induced significant structural changes. Powder X-ray diffraction (PXRD) revealed a reduction in crystallite size from 91 nm to 21 nm and the introduction of microstrain, partially disrupting the MOF's long-range crystalline order, as evidenced by peak broadening and the diminished intensity of high-angle reflections. Particle morphology pre- and post-milling was further studied with scanning electron microscopy (SEM) imaging, verifying a narrow particle size distribution of ± 22 nm after milling. Fourier-transform infrared spectroscopy (FTIR) indicated protonation of carboxylate groups in the larger pores of the framework, likely due to moisture incorporation during milling. Brunauer-Emmett-Teller (BET) surface area analysis showed a substantial decrease in specific surface area from 521 m²/g to 226 m²/g, suggesting a partial collapse of the porous framework. We discuss the applicability of ball milling as a versatile means of post-synthetic approach to reduce MOF particle sizes, a key element in the preparation of MOF-based thin films using inks or polymers.}, language = {en} } @inproceedings{AsgharzadeBartlHausladenetal., author = {Asgharzade, Ali and Bartl, Mathias and Hausladen, Matthias and Chen, Yang and Buchner, Philipp and Edler, Simon and Bachmann, Michael and She, Juncong and Schreiner, Rupert}, title = {Investigation on the influence of internal voltage drops on the emission behavior of silicon field emission arrays using CMOS image sensor}, series = {38th International Vacuum Nanoelectronics Conference (IVNC)}, booktitle = {38th International Vacuum Nanoelectronics Conference (IVNC)}, publisher = {IEEE}, doi = {10.1109/IVNC65669.2025.11120937}, pages = {2}, abstract = {In this paper we report on an improved measurement and analysis method for determining the emission current distribution of field emitter arrays with CMOS sensors. It can also be used for field emission arrays where not all surfaces of the emitters are at the same electrical potential (e.g. for p-doped Si tips, where a strong current saturation occurs). To demonstrate the functionality of this method, a n-doped field emission array was measured using a variable external series resistance. Brightness variations in emission spots were analyzed to re-calculate the known series resistances for comparison. The re-calculated value is in good agreement with the actual value of the resistance. This method offers a quantitative approach to assess internal voltage drop effects on field emission using optical readout}, language = {en} } @phdthesis{Lindner, author = {Lindner, Matthias}, title = {Miniaturisierte dielektrische Barrierenentladungen und ihre Anwendung f{\"u}r das Anti- bzw. De-Icing von aerodynamischen Oberfl{\"a}chen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:384-opus4-1118933}, pages = {XI, 155}, abstract = {Das grundlegende physikalische Verst{\"a}ndnis und die kontinuierliche Weiterentwicklung von dielektrischen Oberfl{\"a}chenbarrierenentladungen (SDBDs) sowie der damit erbundenen elektrischen Diagnostik, sind f{\"u}r eine Vielzahl von Niedertemperaturplasmaanwendungen von entscheidender Bedeutung. In Bezug auf die Anwendung dieser Plasmatechnologie in der Luftfahrt liegt neben der bereits umfassend erforschten aktiven Str{\"o}mungskontrolle zunehmend der Schwerpunkt auf der Vermeidung von Eisablagerungen auf aerodynamischen Komponenten. Die Bildung von Eis auf Oberfl{\"a}chen wie zum Beispiel den Tragfl{\"a}chen kann unter extremen Wetterbedingungen erhebliche Leistungsdefizite hervorrufen und zu ernsthaften Sicherheitsrisiken f{\"u}hren. In Anbetracht der signifikanten Vorteile gegen{\"u}ber traditionellen Enteisungsmethoden steht die Erforschung von SDBDs im Mittelpunkt des anwendungsorientierten Abschnitts dieser Arbeit. Vorliegende Arbeit untergliedert sich in einen grundlegenden und einen anwendungsbezogenen Teil. Darin werden sowohl die physikalischen Eigenschaften und Prozesse von SDBDs analysiert als auch ihre potenziellen Anwendungen in Bezug auf Flugsicherheit und Effizienz untersucht. Die wissenschaftliche Forschung hat in der Vergangenheit erhebliche Anstrengungen unternommen, um ein umfassendes Verst{\"a}ndnis der physikalischen Vorg{\"a}nge, die im Zusammenhang mit SDBDs stehen, zu erarbeiten. Insbesondere die pr{\"a}zise Bestimmung der r{\"a}umlichen Ausdehnung der Entladung entlang der dielektrischen Oberfl{\"a}che - die {\"u}blicherweise in direkter Proportionalit{\"a}t zur Amplitude der angelegten Spannung steht - ist hierbei eine herausfordernde Aufgabe. Diese umfangreichen Studien sind essenziell, um die Entladungseigenschaften und die grundlegenden physikalischen Prozesse zu verstehen, was erhebliche Anwendungspotenziale er{\"o}ffnet. Parallel zu diesen grundlegenden Studien hat sich auch der praktische Einsatz von SDBDs zur Verhinderung der Eisbildung auf aerodynamischen Bauteilen bedeutend weiterentwickelt. Untersuchungen legen nahe, dass L{\"o}sungen auf Basis von SDBDs im Vergleich zu konventionellen Enteisungsmethoden, wie beispielsweise chemischen Enteisungsmitteln oder thermischen Systemen, ein h{\"o}heres Effizienz- und Wirkungspotential besitzen k{\"o}nnten. Allerdings wurden bisherige Entwicklungen von SDBDs haupts{\"a}chlich auf Basis der Leiterplattentechnologie realisiert, was bestimmte Begrenzungen in Bezug auf ihre Anwendbarkeit f{\"u}r Anti-Icing- Technologie mit sich bringt. Im ersten Teil dieser Arbeit wurde die sequentielle Ausbreitung der SDBD-Entladung entlang der dielektrischen Al2O3-Oberfl{\"a}che systematisch analysiert. Die durchgef{\"u}hrten experimentellen Untersuchungen zeigten, dass die Entladungen unmittelbar nach dem Erreichen der Z{\"u}ndspannung einen fest definierten Bereich belegen, der bis zum Erreichen einer kritischen Spannungsamplitude VL stabil bleibt. Anzumerken ist auch, dass das Ausbleiben der Plasmaausbreitung innerhalb dieses Spannungsbereichs zu einer linearen Korrelation zwischen der Entladungsleistung und der angelegten Spannungsamplitude f{\"u}hrt. Diese tiefergehenden Einblicke in die Dynamik der Entladung k{\"o}nnen dazu beitragen, den Einsatz von SDBDs in diversen Anwendungsbereichen effizienter zu gestalten. Im zweiten Teil der Arbeit steht die Entwicklung und Implementierung eines innovativen Ansatzes zur Realisierung von SDBDs im Vordergrund, der auf der Nutzung von D{\"u}nnschichtsubstra-Vten und mikroelektromechanischen Systemen (MEMS) basiert. Die Verwendung dieser Technologie erlaubt einen pr{\"a}ziseren Design- und Fertigungsprozess von Elektrodenstrukturen, was sich positiv auf die Effizienz der Enteisung auswirken kann. Zur Beurteilung des Anti-Icing-Potenzials der entwickelten MEMS-SDBDs wurde ein direkter Vergleich mit konventionellen PCB-SDBDs durchgef{\"u}hrt. Die Ergebnisse legen nahe, dass die 35 μm dicken Elektroden der PCB-SDBDs eine Oberfl{\"a}chenvereisung f{\"o}rdern, die vorrangig durch die Elektrodenkanten induziert wird. Im Gegensatz dazu wurde dieser Effekt bei den deutlich d{\"u}nneren, lediglich 0.3 μm dicken, mittels MEMS gefertigten Elektroden nicht festgestellt. Diese Beobachtungen deuten darauf hin, dass SDBDs, die mit MEMS-Technologien gefertigt wurden, einen signifikanten Vorteil in Anti-Icing-Anwendungen aufweisen k{\"o}nnten und stellen somit einen wesentlichen Fortschritt in der Forschung und Anwendung von SDBDs dar. Die in dieser Arbeit vorgelegten Forschungsergebnisse und innovativen Methoden liefern zahlreiche neue Erkenntnisse, die das Potential besitzen, sowohl das Verst{\"a}ndnis als auch die Anwendung von SDBDs wesentlich zu erweitern. So best{\"a}tigen die Langzeitbelichtungsaufnahmen das neu entdeckte Ph{\"a}nomen einer sequenziellen Ausbreitung des Entladungsplasmas, das bei SDBDs mit dickeren Dielektrika st{\"a}rker ausgepr{\"a}gt ist. Eine neu entwickelte Methodik erm{\"o}glicht die Anwendung der Ladungs-Spannungs-Charakteristik von SDBDs, um essenzielle Parameter f{\"u}r ein vereinfachtes Ersatzschaltbild abzuleiten. Dar{\"u}ber hinaus wurde eine bemerkenswerte numerische {\"U}bereinstimmung zwischen der Ladungs-Spannungs-Charakteristik f{\"u}r den positiven Halbzyklus der Entladung und der aus den optischen Aufnahmen abgeleiteten spannungsabh{\"a}ngigen Reaktorkapazit{\"a}t festgestellt. Diese Erkenntnisse {\"o}ffnen neueWege f{\"u}r die Optimierung und Anwendung von SDBDs in verschiedenen technischen Bereichen. Weiterhin identifizierte die durchgef{\"u}hrte Erosionsstudie Titan als optimal geeignetes Material f{\"u}r MEMS-Elektroden aufgrund seiner hohen Korrosionsbest{\"a}ndigkeit und ausgezeichneten elektrischen Leitf{\"a}higkeit. Es wurden auch Potentiale zur Optimierung von MEMS-SDBDs durch die Auswahl geeigneter dielektrischer Materialien und geeigneter SDBD-Geometrien aufgezeigt. Eine solche Optimierung k{\"o}nnte die Enteisungseffizienz weiter verbessern, indem beispielsweise die dielektrischen Eigenschaften an die spezifischen Anwendungsanforderungen angepasst werden. Innovative Designkonzepte, wie eine gezielte Anordnung der Elektroden oder die Integration von Sensoren zur {\"U}berwachung des Enteisungsprozesses, k{\"o}nnten ebenfalls zur Leistungsf{\"a}higkeit und Zuverl{\"a}ssigkeit von MEMS-SDBDs beitragen. Ein weiterer bedeutender Aspekt ist die Anwendung von Piezotransformatoren zur Generierung der ben{\"o}tigten Hochspannung f{\"u}r SDBD-Systeme. Dieser innovative Ansatz k{\"o}nnte die Effizienz des auf SDBD-Technologie basierenden Enteisungsverfahrens optimieren und somit zur Verbesserung der Leistungsf{\"a}higkeit und Sicherheit von Flugzeugen unter extremen Wetterbedingungen beitragen. Das Forschungsfeld bietet viel Raum f{\"u}r zuk{\"u}nftige Studien, was die Bedeutung und Zukunftsrelevanz der in dieser Arbeit gewonnenen Ergebnisse hervorhebt.}, subject = {Kaltes Plasma}, language = {de} } @phdthesis{Jonker2023, author = {Jonker, Dirk}, title = {Advanced nanofabrication techniques for electron emission devices}, isbn = {978-90-365-5632-3}, doi = {10.3990/1.9789036556323}, pages = {362}, year = {2023}, abstract = {The goal of this thesis is to develop an electron injection source based on a cold field emission cathode that ultimately functions as an alternative electron source used during the Birch reduction process. The experimental configuration to conduct an alternative Birch reduction involves the combination of various physical domains, including solid-state physics, physics of interfaces, electrochemistry, and fluid dynamics. The body of this thesis discusses the fabrication and characterization of a silicon nanocone array. It also presents a self-aligned method to incorporate an electronic gate structure that may function as an extractor grid. The emission behavior and transport properties of the silicon nanocones are assessed by scanning tunneling microscopy by performing measurements on flat silicon and silicon nanocone surfaces containing different dopant types and doping concentrations. Furthermore, additional experimental work is conducted to replace a thermally grown silicon dioxide layer with platinum silicide and characterize the electrical properties by means of scanning tunneling microscopy. Lastly, the thesis discusses the fabrication of two plasmonic structures and evaluates the plasmonic modes, surface enhancement, and Raman activity.}, language = {en} } @phdthesis{Weigl, author = {Weigl, Stefan}, title = {Development of a sensor system for human breath acetone analysis based on photoacoustic spectroscopy}, doi = {10.5283/epub.44776}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:355-epub-447768}, pages = {xlii, 282}, abstract = {The breath analysis section of this thesis outlines the potentials but also emphasises the concomitant challenges of human breath analysis. The section further describes the usefulness of a point-of-care (POC) device for breath acetone detection. In addition, it covers various breath analysis related subjects, which can be useful considering further developments of breath analysers. This includes an extensive summary involving the high abundant endogenous as well as the exogenous breath species present in a clinical environment. Subsequently, a detailed discussion about the theoretical aspects of absorption spectra is provided, forming the basis for the spectral interference chapter. Classical absorption spectroscopy (AS) is compared with photoacoustic spectroscopy (PAS) in view of trace gas analysis. Different modulation schemes for signal generation, i.e. amplitude modulation (AM) and wavelength modulation (WM) are part of the comparison, while the advantages and disadvantages of each technique are highlighted. As a result, PAS is considered superior to AS and hence is selected as the method of choice regarding the development of a sensor for breath acetone detection. A detailed mathematical derivation of the photoacoustic signal generation as well as the signal enhancement by means of acoustic resonance amplification is provided. Moreover, several phenomena causing signal attenuation are outlined, including vibrational-translational (VT) relaxation, vibrational-vibrational (VV) energy transfer mechanism, acoustic detuning and photodissociation. Various simulations regarding spectral interferences in the infra-red (IR) and ultraviolet (UV) region are presented, demonstrating the susceptibility towards spectral cross-sensitivities in the IR region, hence, rather suggesting the UV region for acetone detection. However, this simulation can be easily adopted to other target analytes and serves as a basis for multicomponent analysis approaches in the IR region using tuneable light sources. Ultra sensitive acetone detection employing a high power UV LED is presented and a detailed analysis considering the effects of environmental parameters onto the photoacoustic signal, including temperature, pressure, LED duty cycle and flow rate, is provided. In addition, general cross-sensitivities of the photoacoustic signal towards the high abundant species O2, CO2 and H2O have been investigated and discussed. Moreover, several LED and photoacoustic cell (PAC) combinations have been compared in order to evaluate improvement approaches regarding an enhancement of the system's sensitivity. Finally, photoacoustic sensor setups employing an interband cascade laser (ICL) or a quantum cascade laser (QCL) have been studied and compared to various UV setups in view of different key performance parameters, including the limits of detection (LOD) and the normalised noise equivalent absorption (NNEA) coefficients. The juxtaposition of the different approaches once more emphasises the extraordinary sensitivity of photoacoustic spectroscopy. To the best of the author's knowledge, the LODs (3σ) of the UV LED based photoacoustic measurement in typical breath conditions (12.5 ppbV) and the LOD of the QCL measurement (0.79 ppbV) provide two world records. First, regarding photoacoustic acetone detection using an UV LED and second, in view of other published results for photoacoustic acetone detection in general.}, language = {en} } @article{BuchnerHausladenBartletal., author = {Buchner, Philipp and Hausladen, Matthias and Bartl, Mathias and Bachmann, Michael and Schreiner, Rupert}, title = {High current field emission from Si nanowires on pillar structures}, series = {Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics}, volume = {42}, journal = {Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics}, number = {2}, publisher = {AIP}, issn = {2166-2754}, doi = {10.1116/6.0003384}, abstract = {We investigate the influence of the geometry and doping level on the performance of n-type silicon nanowire field emitters on silicon pillar structures. Therefore, multiple cathodes with 50 by 50 pillar arrays (diameter: 5 μm, height: 30 μm, spacing: 50 μm) were fabricated and measured in diode configuration. In the first experiment, we compared two geometry types using the same material. Geometry 1 is black silicon, which is a highly dense surface covering a forest of tightly spaced silicon needles resulting from self-masking during a plasma etching process of single crystal silicon. Geometry 2 are silicon nanowires, which are individual spaced-out nanowires in a crownlike shape resulting from a plasma etching process of single crystal silicon. In the second experiment, we compared two different silicon doping levels [n-type (P), 1-10 and <0.005 Ω cm] for the same geometry. The best performance was achieved with lower doped silicon nanowire samples, emitting 2 mA at an extraction voltage of 1 kV. The geometry/material combination with the best performance was used to assemble an integrated electron source. These electron sources were measured in a triode configuration and reached onset voltages of about 125 V and emission currents of 2.5 mA at extraction voltages of 400 V, while achieving electron transmission rates as high as 85.0\%.}, language = {en} } @inproceedings{SchreinerMulotGauggeletal., author = {Schreiner, Rupert and Mulot, M. and Gauggel, H. P. and Schweizer, H. and Laue, C. K. and Wallenstein, R.}, title = {Dynamic and spectral properties of red DFB lasers}, series = {Technical Digest. Summaries of papers presented at the Conference on Lasers and Electro-Optics. Postconference Technical Digest (IEEE Cat. No.01CH37170) ; Baltimore, May 6 - 11, 2001 (Trends in optics and photonics series ; 56)}, booktitle = {Technical Digest. Summaries of papers presented at the Conference on Lasers and Electro-Optics. Postconference Technical Digest (IEEE Cat. No.01CH37170) ; Baltimore, May 6 - 11, 2001 (Trends in optics and photonics series ; 56)}, publisher = {IEEE}, isbn = {1-55752-662-1}, doi = {10.1109/CLEO.2001.947498}, pages = {81 -- 82}, abstract = {Summary form only given. Narrow linewidth GaInP/AlGaInP DFB lasers are promising light sources for spectroscopy, for optical data storage systems and for plastic optical fiber WDM applications. However, little is known about the dynamic behavior of red DFB lasers. In this paper, we report on the dynamic and spectral properties of those devices. The lasers were first characterized under cw operation at 25/spl deg/C. Threshold currents are /spl sim/14 mA (475 /spl mu/m length) and /spl sim/18 mA (900 /spl mu/m length). The lasers show stable single mode emission at 680 nm with a SMSR better than -25 dB. The spectral linewidth of the 900 /spl mu/m long devices was measured by using a scanning-Fabry-Perot interferometer.}, language = {en} } @misc{HummelLechner, author = {Hummel, Helmut and Lechner, Alfred}, title = {Miniaturized on-line trace analysis [Patentschrift]}, organization = {Ostbayerische Technische Hochschule Regensburg}, abstract = {The invention relates to a measuring apparatus comprising an apparatus for forming a liquid optical waveguide having a substrate (1) having an at least partially curved closed microchannel (2) having a low-refractive coating (13), whereby there is formed in the substrate (1) at least one feed line (6) for supplying liquid, and whereby there is provided at least at one end of the closed microchannel (2) an apparatus for coupling light axially into the closed microchannel and/or for coupling light axially out of the closed microchannel (2), further comprising a light source (4), a light detector (5), and a first liquid pump (9) which supplies a sample liquid (7) to the closed microchannel (2) via the at least one feed line (6, 6a).}, language = {de} } @article{TanSchreinerHausladenetal., author = {Tan, Jing Jie and Schreiner, Rupert and Hausladen, Matthias and Asgharzade, Ali and Edler, Simon and Bartsch, Julian and Bachmann, Michael and Schels, Andreas and Kwan, Ban-Hoe and Ng, Danny Wee-Kiat and Hum, Yan-Chai}, title = {SiMiC: Context-aware silicon microstructure characterization using attention-based convolutional neural networks for field-emission tip analysis}, series = {Journal of Vacuum Science \& Technology B}, volume = {43}, journal = {Journal of Vacuum Science \& Technology B}, number = {6}, publisher = {AVS}, doi = {10.1116/6.0005068}, abstract = {Accurate characterization of silicon microstructures is essential for advancing microscale fabrication, quality control, and device performance. Traditional analysis using scanning electron microscopy (SEM) often requires labor-intensive, manual evaluation of feature geometry, limiting throughput and reproducibility. In this study, we propose SiMiC: Context-aware Silicon Microstructure Characterization Using Attention-based Convolutional Neural Networks for Field-Emission Tip Analysis. By leveraging deep learning, our approach efficiently extracts morphological features—such as size, shape, and apex curvature—from SEM images, significantly reducing human intervention while improving measurement consistency. A specialized dataset of silicon-based field-emitter tips was developed, and a customized convolutional neural network architecture incorporating attention mechanisms was trained for multiclass microstructure classification and dimensional prediction. Comparative analysis with classical image processing techniques demonstrates that SiMiC achieves high accuracy while maintaining interpretability. The proposed framework establishes a foundation for data-driven microstructure analysis directly linked to field-emission performance, opening avenues for correlating emitter geometry with emission behavior and guiding the design of optimized cold-cathode and SEM electron sources. The related dataset and algorithm repository that could serve as a baseline in this area can be found at https://research.jingjietan.com/?q=SIMIC.}, language = {en} } @inproceedings{BarikRawatMannaetal., author = {Barik, Ranjan Kumar and Rawat, Vikram Singh and Manna, Subhrajit and Bandyopadhyay, Ayan Kumar and Hausladen, Matthias and Asgharzade, Ali and Schreiner, Rupert}, title = {On Chip Electron Gun Design Using Silicon Tip Field Emitter Array}, series = {2025 IEEE Microwaves, Antennas, and Propagation Conference (MAPCON), 14-18. Dezember 2025, Kochi, India}, booktitle = {2025 IEEE Microwaves, Antennas, and Propagation Conference (MAPCON), 14-18. Dezember 2025, Kochi, India}, publisher = {IEEE}, isbn = {979-8-3315-3722-7}, doi = {10.1109/MAPCON65020.2025.11426578}, pages = {4}, abstract = {Silicon based silicon tip array emitter has developed at OTH Regensburg, Germany. This array emitter is the basis for development of a novel electron gun. This field emitter electron sources were fabricated using laser-micromachining technique followed by MEMS technology. In this work, the design and development of electron gun using complete silicon structure is reported. The goal of this work is to develop electron gun using less effort, easy and hassle free technique.}, language = {en} }