TY - JOUR A1 - Michaeli, Walter A1 - Stollenwerk, Manfred A1 - Telgenbüscher, Klaus A1 - Leiber, Jörn T1 - Vorbehandeln und Beschichten von Kunststoffteilen in PE-CVD-Anlagen JF - Maschinenmarkt KW - Kunststoffprodukt KW - Oberflächenbehandlung Y1 - 1993 VL - 99 IS - 29 SP - 42 EP - 48 ER - TY - JOUR A1 - Michaeli, Walter A1 - Telgenbüscher, Klaus A1 - Leiber, Jörn A1 - Stollenwerk, Manfred T1 - Plasmapolymerisation zur Veredelung von Kunststoffoberflächen JF - Dünne Schichten KW - Plasmapolymerisation KW - Kunststoffprodukt KW - Oberflächenbehandlung Y1 - 1992 VL - 1992 IS - 3 SP - 34 EP - 38 ER - TY - JOUR A1 - Michaeli, Walter A1 - Leiber, Jörn A1 - Telgenbüscher, Klaus A1 - Stollenwerk, Manfred T1 - Plasmapolymerisation: Kunststoffe beschichten JF - Industrieanzeiger KW - Plasmapolymerisation Y1 - 1992 VL - 1992 IS - 43 SP - 58 EP - 60 ER - TY - CHAP A1 - Stollenwerk, Manfred A1 - Michaeli, Walter A1 - Telgenbüscher, Klaus A1 - Leiber, Jörn A1 - Londschein, Martin T1 - Verbesserung von Verbundwerkstoffen durch Plasmabehandlung der Verstärkungsfasern KW - Faserverstärkter Kunststoff Y1 - 1992 N1 - 31. Internationale Chemiefasertagung Dornbirn, Österreich, September 1992 ER - TY - JOUR A1 - Stollenwerk, Manfred A1 - Grützmacher, Detlev T1 - GaInAs/GaInAsP SC-MQW-laser emitting at 1.35 µm grown by LP-MOVPE JF - Microelectronic Engineering KW - Quantenwell-Laser KW - Galliumarsenid KW - Indiumarsenid Y1 - 1991 VL - 1991 IS - 15 SP - 263 EP - 266 ER - TY - CHAP A1 - Stollenwerk, Manfred A1 - Grützmacher, Detlev A1 - Heime, Klaus A1 - Möhrle, Martin A1 - Fidorra, Frank T1 - GaInAs/GaInAsP SC-MQW Laser mit einer Emissionswellenlänge von 1,35 µm deponiert mit Hilfe der LP-MOVPE KW - Quantenwell-Laser KW - Galliumarsenid KW - Indiumarsenid Y1 - 1991 N1 - Beitrag zum Kolloquium “Photonische Komponenten“, Universität Ulm, April 1991 ER - TY - CHAP A1 - Stollenwerk, Manfred A1 - Grützmacher, Detlev A1 - Schwedler, Ralf A1 - Meyer, R. A1 - Hardtdegen, Hilde A1 - Kux, A. A1 - Heime, Klaus T1 - Systematic study of strained GaInAs/InP grown by MOVPE KW - Galliumarsenid KW - Indiumarsenid Y1 - 1991 N1 - 4th European workshop on metallorganic vapour phase epitaxy, Nijmegen, NL, 1991 ER - TY - JOUR A1 - Oschinowo, John A1 - Forchel, Alfred A1 - Grützmacher, Detlev A1 - Stollenwerk, Manfred A1 - Heuken, Michael A1 - Heime, Klaus T1 - Photoluminescence study of interdiffusion in In0,53Ga0,47/As/InP surface quantum wells JF - Applied Physics Letters N2 - We have investigated the thermal stability and interdiffusion of In0.53Ga0.47As/InP surface quantum wells. In these structures the optically active InGaAs layer is bounded on one side by vacuum and on the other side by InP. We obtain well‐defined photoluminescence emission spectra with high intensity. After rapid thermal annealing at temperatures between 500 and 900 °C (annealing time 1 min) we observe strong emission energy shifts of up to 316 meV. By using a simple model of ion intermixing we estimate large interdiffusion coefficients (e.g., 1.7×10−14 cm2 s−1 for T=900 °C) and an activation energy of 1.3 eV for the surface quantum wells. KW - Photolumineszenz Y1 - 1992 VL - 60 IS - 21 SP - 2660 EP - 2662 ER - TY - CHAP A1 - Oschinowo, John A1 - Forchel, Alfred A1 - Grützmacher, Detlev A1 - Stollenwerk, Manfred T1 - RTA study of thermal stability and interdiffusion of InGaAs/InP quantum wells - the influence of InGaAs cap layers T2 - Third International Conference Indium Phosphide and Related Materials Cardiff/Wales N2 - A study of the thermal stability of InGaAs/InP quantum wells with different top barrier compositions that used rapid thermal annealing at temperatures between 600 degrees C and 950 degrees C (annealing time 1 min) is discussed. The thermal interdiffusion effects were evaluated by photoluminescence spectroscopy. From the temperature dependence of the luminescence energy shifts the interdiffusion coefficients and activation energies are determined. KW - Photolumineszenzspektroskopie KW - Indiumarsenid KW - Galliumarsenid KW - Indiumphosphid Y1 - 1991 SP - 606 EP - 609 ER - TY - JOUR A1 - Shi, Chang-Xin A1 - Grützmacher, Detlev A1 - Stollenwerk, Manfred A1 - Wang, Qing-Kang A1 - Heime, Klaus T1 - High-performance undoped InP/n-InP/GaAs MSM photodetectors grown by LP-MOVPE JF - IEEE Transactions on Electron Devices KW - Indiumarsenid KW - Galliumarsenid Y1 - 1992 VL - 39 IS - 5 SP - 1028 EP - 1031 PB - IEEE ER - TY - JOUR A1 - Stollenwerk, Manfred A1 - Döhring, Thorsten A1 - Freudenmann, Dominic A1 - Schäfer, Tobias A1 - Stadtmüller, Johannes A1 - Röcke, Nicole T1 - Sputtered highly effective iridium catalysts: a new approach for green satellite propulsion JF - Journal of Materials Science N2 - This work demonstrated the large potential of sputtered iridium metal for catalytic reactions shown by the example of decomposition of hydrogen peroxide (H2O2) for space propulsion systems. For this purpose, iridium was coated onto Al2O3 pellets by a sputter process under varied process parameters. Depending on previously selected parameters, the obtained metal-loaded pellets offer closed- and/or open-shell structures. Catalytic productivity of these first-generation iridium-sputtered catalysts was estimated in laboratory experiments and compared to platinum-loaded pellets. Under optimized sputter-process conditions, the reactivity is significantly improved compared to the platinum-impregnated pellets. The better catalytic productivity can be explained by the increased active surface area of the iridium layers on the pellets. The surface morphology and the microstructure of the iridium coating can be actively controlled by the sputter pressure. The results are in accordance with the sputtering process pressure tendency described by the Thornton Structure–Zone Model. KW - Iridium KW - Katalysator KW - Satellitentechnik Y1 - 2021 U6 - https://doi.org/https://doi.org/10.1007/s10853-021-05897-z VL - 2021 IS - 2021 SP - 1 EP - 11 ER - TY - GEN A1 - Döhring, Thorsten A1 - Stollenwerk, Manfred A1 - Stadtmüller, Johannes A1 - Freudenmann, Dominic A1 - Röcke, Nicole T1 - Nanostructured iridium catalysts for effective hydrogen peroxide decomposition T2 - EuroNanoForum N2 - The EU intends to restrict the use of critical fuels in space propulsion systems. These propellants like hydrazine are chemically aggressive, toxic and carcinogenic. Space propulsion of the future should be environmentally friendly, inexpensive, and easy to handle. Aschaffenburg University and DLR are currently developing environmentally friendly technologies for future satellite engines. Thereby rocket-grade hydrogen peroxide, which is foreseen as a substitute, is converted to uncritical water vapour and oxygen by an exothermic catalytic reaction on nanostructured iridium layers. The resulting hot gases provide the required amount of thrust. The iridium catalyst layers are coated onto ceramic pellets, using RF magnetron sputtering technology. The catalytic functionality was tested afterwards at the chemical laboratories of DLR. First experimental results show a significantly higher catalytic activity for nanostructured iridium surfaces than for smoother crystalline layers. N2 - Poster KW - satellite KW - propulsion KW - catalyst KW - iridium KW - hydrogen peroxide KW - Iridium KW - Katalysator KW - Satellitentechnik Y1 - 2021 VL - 2021 ER - TY - CHAP A1 - Stanik, Eva A1 - Döhring, Thorsten A1 - Pregler, Jan A1 - Stollenwerk, Manfred A1 - Hildenbrand, Georg T1 - Spectral measurements and life science experiments using extreme radiation exposures at high altitude T2 - Proceedings of SPIE N2 - The ASTRABAX project ("Aschaffenburg Stratospheric Balloon Experiment"), being funded for the years 2024 to 2026, is designed as a multimodal platform for the investigation of radiation exposures at high altitude. The UV-C spectral region is of special interest. Spectral measurements observe this region of interest using miniature UV-VIS spectrometers. The platform also contains a radiation dosimetry, a power source for on-board electronics, and common shielding setups for multiple spectral combinations. Human cells are exposed simultaneously to radiation of different compositions as particle, X-ray and UV radiation. After the flight, possible changes in the spatial chromatin organization are examined. Material samples intended for the development of satellite components are irradiated also. Investigations under such conditions are realistic and crucial for high altitude flights in the atmosphere, for space flights as well as for comparable exposures on other objects of the solar system, and even for exoplanet habitats to some extent. KW - Ultraviolet radiation KW - Balloons KW - Solar radiation KW - Spectrometers KW - Diffusers KW - Spektroskopie KW - Messung KW - Ultraviolett KW - Sonnenstrahlung Y1 - 2024 UR - https://doi.org/10.1117/12.3028519 U6 - https://doi.org/10.1117/12.3028519 VL - 2024 IS - 13024 SP - 130240M EP - 130240M ER - TY - GEN A1 - Döhring, Thorsten A1 - Stanik, Eva A1 - Pregler, Jan A1 - Stollenwerk, Manfred A1 - Hildenbrand, Georg T1 - Forschung zu Strahlenschäden mit dem Stratosphärenballon-Experiment ASTRABAX N2 - Das für die Jahre 2024 bis 2026 geförderte Projekt ASTRABAX („Aschaffenburger Stratosphärenballon- Experiment“) ist als multimodale Plattform der Material- und Biowissenschaften für Untersuchungen bei extremen Strahlenbelastungen in großer Höhe konzipiert. Dabei ist der UV-C-Spektralbereich von besonderem Interesse und wird mit Miniatur-UV-Spektrometern untersucht. Die Plattform des Ballonexperimentes umfasst eine gemeinsame Strahlungsdosimetrie, eine Stromquelle für die Bordelektronik und Abschirmungen für mehrere Bestrahlungskombinationen. Biologische Zellen werden Kombinationen aus Partikel-, Röntgen- und UV-Strahlung ausgesetzt. Nach dem Flug werden mögliche Veränderungen in der räumlichen Chromatinorganisation mittels hochauflösender Mikroskopie untersucht. Auswirkungen von Kombinationen aus hoch- und niederenergetischer Strahlung sind bisher nicht ausreichend erforscht und beschrieben. Zusätzlich werden auch für Satelliten relevante Materialproben bestrahlt. Untersuchungen unter solchen Bedingungen sind realistisch und relevant für Flüge in der Stratosphäre, für Raumflüge sowie für vergleichbare Expositionen bei anderen Objekten des Sonnensystems oder Exoplaneten-Habitaten. N2 - Poster KW - Weltraumtechnik KW - Radiometrie KW - Biomedizin KW - Stratosphären-Ballon KW - Strahlenbelastung Y1 - 2024 UR - https://www.dgao-proceedings.de/abstract/abstract_only.php?id=3018 SP - 1 EP - 1 ER - TY - CHAP A1 - Mann, Michael A1 - Wenzler, Sebastian A1 - Döhring, Thorsten A1 - Stollenwerk, Manfred A1 - Pribulla, Theodor A1 - Sivanič, Peter A1 - Komžík, Richard ED - Karl Friedrich, Zieghahn T1 - Stromversorgung als Umweltfaktor: Analyse der elektrischen Netzqualität in astronomischen Observatorien T2 - Umwelteinflüsse erfassen, simulieren, bewerten KW - Netzqualität KW - Astronomische Observatorien KW - EMV KW - Erdung KW - Sternwarte KW - Elektrizitätsversorgung Y1 - 2022 SN - 978-3-9818507-7-2 VL - 2022 SP - 193 EP - 207 PB - Gesellschaft für Umweltsimulation e.V. ER - TY - GEN A1 - Stanik, Eva A1 - Döhring, Thorsten A1 - Pregler, Jan A1 - Stollenwerk, Manfred A1 - Hildenbrand, Georg T1 - Spectral measurements and life science experiments using extreme radiation exposures at high altitude N2 - The ASTRABAX project ("Aschaffenburg Stratospheric Balloon Experiment"), being funded for the years 2024 to 2026, is designed as a multimodal platform for the investigation of radiation exposures at high altitude. Miniature UV-VIS spectrometers observe the UV-C spectral region. The platform also contains a radiation dosimetry, a power source for on-board electronics, and common shielding setups for multiple spectral combinations. The effects of combinations of high- and low-energy rays on human cells haven´t been sufficiently investigated and described so far. Investigations under such conditions are realistic and crucial for high altitude flights in the atmosphere, for space flights as well as for comparable exposures on other objects of the solar system, and even for exoplanet habitats to some extent. N2 - Poster KW - Balloons KW - Diffusers KW - Solar radiation KW - Spectrometers KW - Ultraviolet radiation KW - Stahlenbelastung KW - Stratosphären-Ballon Y1 - 2024 ER - TY - CHAP A1 - Mann, Michael A1 - Döhring, Thorsten A1 - Stollenwerk, Manfred A1 - Priebsch, Alessandro A1 - Pribulla, Theodor A1 - Komžík, Richard M. A1 - Sivanic, Peter ED - Storrie-Lombardi, Lisa J. ED - Benn, Chris R. ED - Chrysostomou, Antonio T1 - Advanced power quality measurement techniques at the electric power grid of astronomical observatories T2 - Observatory Operations: Strategies, Processes, and Systems X, Conference of SPIE 13098, 17 - 20 June 2024 KW - Sternwarte KW - Elektrizitätsversorgung Y1 - 2024 U6 - https://doi.org/10.1117/12.3016562 PB - SPIE ER - TY - CHAP A1 - Mann, Michael A1 - Döhring, Thorsten A1 - Stollenwerk, Manfred A1 - Wenzler, Sebastian A1 - Pribulla, Theodor A1 - Komžík, Richard M. A1 - Sivanic, Peter ED - Benn, Chris R. ED - Seaman, Robert L. ED - Adler, David S. T1 - On the importance of the electrical grid power quality for astronomical observatories T2 - Proceedings of SPIE: Observatory Operations: Strategies, Processes, and Systems IX KW - Elektrizitätsversorgung KW - Sternwarte Y1 - 2022 U6 - https://doi.org/http://dx.doi.org/10.1117/12.2627227 PB - SPIE ER - TY - CHAP A1 - Döhring, Thorsten A1 - Stanik, Eva A1 - Pregler, Jan A1 - Stollenwerk, Manfred A1 - Hildenbrand, Georg T1 - Forschung zu Strahlenschäden mit dem Stratosphärenballon-Experiment ASTRABAX T2 - DGaO-Proceedings N2 - Das Stratosphärenballon-Experiment ASTRABAX ist als multimodale Plattform der Material- und Biowissenschaften für Untersuchungen bei extremen Strahlenbelastungen konzipiert, mit Fokus auf dem UV-C-Spektralbereich und der kosmischen Höhenstrahlung. Auswirkungen von Kombinationen aus hoch- und niederenergetischer Strahlung sind relevant, jedoch nicht ausreichend erforscht. KW - Stratosphärenballon KW - Dosimetrie KW - UV-Spektroskopie KW - kosmische Strahlung KW - Strahlenschäden KW - Stratosphären-Ballon KW - Strahlenbelastung Y1 - 2024 UR - https://www.dgao-proceedings.de/download/125/125_p21.pdf VL - 2024 IS - 125 SP - 1 EP - 2 ER - TY - JOUR A1 - Amorim, Isilda A1 - Spera, Natalia C.M. A1 - Nicoara, Nicoleta A1 - Ramasamy, Devaraj A1 - Alves, Diana F. A1 - Stollenwerk, Manfred A1 - Stadtmüller, Johannes A1 - Döhring, Thorsten A1 - Sadewasser, Sascha A1 - Kolen'ko, Yury V. A1 - Sousa, Juliana P.S. T1 - Overall alkaline water electrolysis over active, stable, low loading iridium catalysts sputtered on nickel foam JF - International Journal of Hydrogen Energy KW - Iridium KW - Katalysator KW - Wasserstoffelektrolyse KW - Wasser KW - Elektrolyse KW - Wasserstofferzeugung Y1 - 2024 U6 - https://doi.org/10.1016/j.ijhydene.2024.10.306 SN - 0360-3199 VL - 92 SP - 852 EP - 864 PB - Elsevier BV ER - TY - CHAP A1 - Wissel, Julian A1 - Freudenmann, Dominic A1 - Perez, Nicolas A1 - Döhring, Thorsten A1 - Stadtmüller, Johannes A1 - Stollenwerk, Manfred T1 - Various highly effective sputtered layer structures as catalysts for H2O2 decomposition for use in satellite engines T2 - MaterialsWeek 2025 – Book of Abstracts N2 - Catalysts are frequently employed in both research and industrial applications to facilitate or accelerate chemical reactions. One such application is in monopropellant thrusters for space propulsion systems, where hydrogen peroxide (H2O2) is used as a liquid propellant. The decomposition of liquid hydrogen peroxide into water and oxygen gas, which ultimately generates thrust, can be achieved using noble metal catalysts from the platinoid group, such as platinum and iridium. This promotes the use of more environmentally friendly and less toxic propellants, such as H2O2, instead of hydrazine and nitrogen tetroxide (NTO). The optimization of coating structures with these catalytic materials is essential for future space applications, as it aims to extend the lifespan of catalyst materials and results in a better utilization of H2O2 in satellite engines. Therefore, different layer structures were deposited onto Duranit D99 pellets using a controlled magnetron sputtering process. Previous studies have shown that the used sputtering pressure has a strong influence on the structure of the deposited coatings [2][3]. Certain parameter combinations produce catalytic layers with rough textures and a highly porous microstructure, see figure 1 [1]. To improve the thermal and mechanical stability of the sputtered layers, thin adhesive layers of Titanium and Zirconium were applied beneath the catalytic layer. The pellets were then heated in an oven at 640°C for one minute to simulate the thermal effects experienced in a satellite engine during ignition. Following this, the catalytic performance of the pellets was tested in laboratory experiments using 30% H2O2. Pellets with sputtered platinum as the catalytic coating delivered the best results. These coatings will be further evaluated in an engine test conducted at the German Aerospace Centre (DLR). Hydrogen peroxide is also expected to play a crucial role in future lunar and Martian colonization efforts. In this context, catalytic coatings would be used to decompose H2O2 to supply astronauts with water and oxygen, rather than to generate thrust in satellite engines. KW - catalyst KW - satellite propulsion KW - sputtered layers KW - iridium KW - platinum KW - Satellitentechnik KW - Katalysator Y1 - 2025 SN - 978-3-88355-446-4 SP - 53 EP - 53 PB - Deutsche Gesellschaft für Materialkunde e.V. (DGM) CY - Sankt Augustin ER -