@article{VorholtWittrock2015, author = {Vorholt, Christian and Wittrock, Ulrich}, title = {Intra-cavity pumped Yb:YAG thin-disk laser with 1.74\% quantum defect}, series = {Opt. Lett.}, volume = {40}, journal = {Opt. Lett.}, doi = {10.25974/fhms-828}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-8284}, pages = {4819 -- 4822}, year = {2015}, abstract = {We present, to the best of our knowledge, the first intracavity pumped Yb:YAG thin-disk laser. It operates at 1050.7 nm with a quantum defect of just 1.74\% due to pumping at 1032.4 nm. Low absorption of the pump light at the pump wavelength of 1032.4 nm is compensated for by placing the disk inside the resonator of another Yb:YAG thin-disk laser which is diode-pumped at 940 nm. The intra-cavity pumped laser has an output power of 10.3 W and a slope efficiency of 8.3\%}, language = {en} } @article{KazasidisVerpoortSolovievetal.2018, author = {Kazasidis, Orestis and Verpoort, Sven and Soloviev, Oleg and Vdovin, Gleb and Verhaegen, Michel and Wittrock, Ulrich}, title = {Extended-image-based correction of aberrations using a deformable mirror with hysteresis}, series = {Opt. Expr.}, volume = {26}, journal = {Opt. Expr.}, doi = {10.1364/OE.26.027161}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-14759}, pages = {27161 -- 27178}, year = {2018}, abstract = {With a view to the next generation of large space telescopes, we investigate guide-star-free, image-based aberration correction using a unimorph deformable mirror in a plane conjugate to the primary mirror. We designed and built a high-resolution imaging testbed to evaluate control algorithms. In this paper we use an algorithm based on the heuristic hill climbing technique and compare the correction in three different domains, namely the voltage domain, the domain of the Zernike modes, and the domain of the singular modes of the deformable mirror. Through our systematic experimental study, we found that successive control in two domains effectively counteracts uncompensated hysteresis of the deformable mirror.}, language = {en} } @inproceedings{SauvageAmiauxAustinetal.2016, author = {Sauvage, Marc and Amiaux, J{\´e}rome and Austin, James and Bello, Mara and Bianucci, Giovanni and Chesn{\´e}, Simon and Citterio, Oberto and Collette, Christophe and Correia, S{\´e}bastien and Durand, Gilles A. and Molinari, Sergio and Pareschi, Giovanni and Penfornis, Yann and Sironi, Giorgia and Valsecchi, Guiseppe and Verpoort, Sven and Wittrock, Ulrich}, title = {A development roadmap for critical technologies needed for TALC: a deployable 20m annular space telescope}, series = {Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave, Proc. SPIE}, volume = {9904}, booktitle = {Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave, Proc. SPIE}, doi = {10.25974/fhms-924}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-9248}, pages = {99041L}, year = {2016}, abstract = {Astronomy is driven by the quest for higher sensitivity and improved angular resolution in order to detect fainter or smaller objects. The far-infrared to submillimeter domain is a unique probe of the cold and obscured Universe, harboring for instance the precious signatures of key elements such as water. Space observations are mandatory given the blocking effect of our atmosphere. However the methods we have relied on so far to develop increasingly larger telescopes are now reaching a hard limit, with the JWST illustrating this in more than one way (e.g. it will be launched by one of the most powerful rocket, it requires the largest existing facility on Earth to be qualified). With the Thinned Aperture Light Collector (TALC) project, a concept of a deployable 20 m annular telescope, we propose to break out of this deadlock by developing novel technologies for space telescopes, which are disruptive in three aspects: \&\#8226; An innovative deployable mirror whose topology, based on stacking rather than folding, leads to an optimum ratio of collecting area over volume, and creates a telescope with an eight times larger collecting area and three times higher angular resolution compared to JWST from the same pre-deployed volume; \&\#8226; An ultra-light weight segmented primary mirror, based on electrodeposited Nickel, Composite and Honeycomb stacks, built with a replica process to control costs and mitigate the industrial risks; \&\#8226; An active optics control layer based on piezo-electric layers incorporated into the mirror rear shell allowing control of the shape by internal stress rather than by reaction on a structure. We present in this paper the roadmap we have built to bring these three disruptive technologies to technology readiness level 3. We will achieve this goal through design and realization of representative elements: segments of mirrors for optical quality verification, active optics implemented on representative mirror stacks to characterize the shape correction capabilities, and mechanical models for validation of the deployment concept. Accompanying these developments, a strong system activity will ensure that the ultimate goal of having an integrated system can be met, especially in terms of (a) scalability toward a larger structure, and (b) verification philosophy.}, language = {en} } @article{BialuschewskiHoppiusFrohnhovenetal.2018, author = {Bialuschewski, Danny and Hoppius, Jan S. and Frohnhoven, Robert and Deo, Meenal and G{\"o}n{\"u}ll{\"u}, Yakup and Fischer, Thomas and Gurevich, Evgeny L. and Mathur, Sanjay}, title = {Laser-Textured Metal Substrates as Photoanodes for Enhanced PEC Water Splitting Reactions}, series = {Adv. Eng. Materials}, volume = {20}, journal = {Adv. Eng. Materials}, doi = {10.1002/adem.201800167}, pages = {1800167}, year = {2018}, language = {en} } @book{LaurigHoelscher2004, author = {Laurig, Wolfgang and H{\"o}lscher, Uvo}, title = {Ergonomie-Leitfaden f{\"u}r die Gestaltung von Medizinprodukten}, publisher = {Mignon-Verlag}, address = {Bonn}, doi = {10.25974/fhms-239}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-2399}, publisher = {FH M{\"u}nster - University of Applied Sciences}, year = {2004}, abstract = {Ziel der Studie war, ausgehend von einer Gef{\"a}hrdungsanalyse und einer Risikoeinsch{\"a}tzung, einen Leitfaden zur systematischen Ber{\"u}cksichtigung der relevanten ergonomischen Aspekte bei der Gestaltung von Medizinprodukten zu erarbeiten. Hierzu sollte der f{\"u}r die Maschinennormung entwickelte Ergonomie-Leitfaden EN 13861 an die besonderen Anforderungen bei der Gestaltung von Medizinprodukten angepasst werden.}, language = {de} } @article{CarlHochmann2022, author = {Carl, Ann-Kathrin and Hochmann, David}, title = {Comparison of the regulatory requirements for custom-made medical devices using 3D printing in Europe, the United States, and Australia}, series = {Biomedical Engineering / Biomedizinische Technik}, volume = {67}, journal = {Biomedical Engineering / Biomedizinische Technik}, number = {6}, issn = {1862-278X}, doi = {10.1515/bmt-2021-0266}, pages = {61 -- 69}, year = {2022}, abstract = {Additive manufacturing (AM) has continuously grown in recent decades. Enhanced quality, further development of technology, and fall in prices make AM applicable and capable for various industrial applications, also for the manufacture of medical devices. 3D printing offers the possibility for an unprecedented adaptation to the anatomy of each patient, generating medical devices on a case-by-case basis. In many jurisdictions, custom-made devices qualify for an exemption to pre-market approval standards. This regulation is called into question by new technologies, like AM. Therefore, this article compares the current regulatory requirements for custom-made devices in Europe, the United States, and Australia and discusses the impact on 3D printed devices. It concludes that not all jurisdictions have yet adjusted their regulatory framework for custom-made devices to technological advances. Remaining uncertainties must be eliminated in order to help manufacturers comply with the regulatory requirements, emphasizing key aspects of AM.}, language = {en} } @article{DeichselRaschkeHerbstetal.2022, author = {Deichsel, Adrian and Raschke, Michael J. and Herbst, Elmar and Peez, Christian and Oeckenp{\"o}hler, Simon and Briese, Thorben and Wermers, Jens and Kittl, Christoph and Glasbrenner, Johannes}, title = {The Biomechanical Stability of Bone Staples in Cortical Fixation of Tendon Grafts for Medial Collateral Ligament Reconstruction Depends on the Implant Design}, series = {The American Journal of Sports Medicine}, volume = {50}, journal = {The American Journal of Sports Medicine}, number = {14}, issn = {1552-3365}, doi = {10.1177/03635465221130753}, pages = {3827 -- 3831}, year = {2022}, language = {en} } @article{Hoelscher2004, author = {H{\"o}lscher, U.}, title = {Neuordnung der Sicherheitskonzepte f{\"u}r medizinische elektrische Medizinger{\"a}te}, series = {mt-Medizintechnik}, journal = {mt-Medizintechnik}, number = {2}, issn = {0344-9416}, pages = {42 -- 45}, year = {2004}, language = {de} } @article{RauschVerpoortWittrock2016, author = {Rausch, Peter and Verpoort, Sven and Wittrock, Ulrich}, title = {Unimorph deformable mirror for space telescopes: environmental testing}, series = {Opt. Expr.}, volume = {24}, journal = {Opt. Expr.}, doi = {10.25974/fhms-853}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-8530}, pages = {1528 -- 1542}, year = {2016}, abstract = {We have developed and manufactured a unimorph deformable mirror for space telescopes based on piezoelectric actuation. The mirror features 44 actuators, has an aperture of 50 mm, and is designed to reproduce low-order Zernike modes with a stroke of several tens of µm. We assessed the space compliance by operating the mirror in thermal vacuum, and exposing it to random and sinusoidal vibrations, as well as to ionizing irradiation. Additionally, the operational life time and the laser power handling capability were tested. The mirror was successfully operated in thermal vacuum at 100 K. We report on the conducted tests and the methods used to evaluate the mirror\&\#180;s performance, and discuss the compliance with the demanded requirements}, language = {de} } @inproceedings{RauschVerpoortWittrock2014, author = {Rausch, Peter and Verpoort, Sven and Wittrock, Ulrich}, title = {Performance verification and environmental testing of a unimorph deformable mirror for space applications.}, series = {Proceedings of the 10th International Conference on Space Optics - ICSO, Tenerife, Spain}, booktitle = {Proceedings of the 10th International Conference on Space Optics - ICSO, Tenerife, Spain}, publisher = {FH M{\"u}nster}, doi = {10.25974/fhms-771}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-7716}, year = {2014}, abstract = {Concepts for future large space telescopes require an active optics system to mitigate aberrations caused by thermal deformation and gravitational release. Such a system would allow on-site correction of wave-front errors and ease the requirements for thermal and gravitational stability of the optical train. In the course of the ESA project "Development of Adaptive Deformable Mirrors for Space Instruments" we have developed a unimorph deformable mirror designed to correct for low-order aberrations and dedicated to be used in space environment. We briefly report on design and manufacturing of the deformable mirror and present results from performance verifications and environmental testing.}, language = {en} }