Development of laser positioning system of high accuracy in the nanometer range. - In: Advanced Fabrication Technologies for Micro/Nano Optics and Photonics XI, (2018), 105440E, insges. 7 S.
Direct Laser Writing techniques like two-photon-polymerization or UV-lithography have become common tools for the micro- and nanofabrication of precise devices like photonic crystals. A decrease in the size of structures of special devices requires a significant better resolution of the laser beam system that can be determined by using different photoinitiators or a second depletion laser for STED-lithography. However, besides the optical limits for the resolution of the laser system due to diffraction effects, the positioning systems for the laser beam or the sample stage lead to further imprecisenesses. To benefit from the high resolution techniques for the structuring process, the need for highly accurate positioning systems has dramatically grown during the last years. A combination of lithographic techniques with a nanopositioning and nanomeasuring machine NMM-1, developed at the TU Ilmenau, enables high precision structuring capability in an extended range. The large positioning volume of 25mm x 25mm x 5mm with a resolution in the sub-nanometer range is a good condition for ultra precision manufacturing with large area 3D-Laser-Lithography. Advantages and disadvantages as well as further developments of the NMM-1 system will be discussed related to current developments in the laser beam and nanopositioning system optimization. Part of the further development is an analysis of the implementability of additional ultra precise rotational systems in the NMM-1 for the unlimited addressability perpendicular to the surface of a hemisphere as key strategy for multiaxial nanopositioning and nanofabrication systems.
https://doi.org/10.1117/12.2312704
Self-organization of pristine C60 fullerene and its complexes with chemotherapy drugs in aqueous solution as promising anticancer agents. - In: Modern Problems of Molecular Physics, (2018), S. 3-22
Im Titel ist "60" tiefgestellt
https://doi.org/10.1007/978-3-319-61109-9_1
Methods for temperature determination of electrical discharges generated by opening contacts in explosive gas mixtures :
Methoden der Temperaturbestimmung von elektrischen Entladungen bei Öffnungs-Kontaktvorgängen in zündfähigen Gasen. - In: Technisches Messen, ISSN 2196-7113, Bd. 85 (2018), 1, S. 56-64
Für elektrische Entladungen, die bei niedrigen Spannungen von 20-40V und Strömen von 40-100mA nach der Öffnung eines elektrischen Kontaktes in explosiven Atmosphären auftreten, wurden erste spektroskopische Untersuchungen hinsichtlich der dabei entstehenden Temperatur durchgeführt. Diese Metalldampf-Entladungen, die ähnlich dem "kurzen Bogen" (short arc) sind, werden im international standardisierten Funkenprüfgerät gemäß IEC 60079-11 erzeugt, um die Eignung elektrischer Komponenten in explosionsgeschützten Bereichen zu beurteilen. - Die Temperatur ist bei diesen komplexen Zündvorgängen, die im Funkenprüfgerät auftreten, ein Schlüsselparameter. Einerseits ist die Temperatur der Kontaktmaterialien für die Beurteilung der zwingend erforderlichen Vorprozesse vor der Hauptentladung relevant, andererseits kann die Wirkung der Entladung durch die Elektronen-, Ionen und Gastemperatur charakterisiert werden. Dieser Artikel beschreibt den aktuellen Stand zur Temperaturmessung dieser elektrischen Entladungen, einschließlich der Herausforderungen, die dem genaueren Verständnis dieser Entladungsvorgänge und des thermochemischen Zündprozesses dienen sollen. Für Entladungen mit 30V und 100mA unter den genannten Rahmenbedingungen wurden Anregungstemperaturen im Bereich von 3500-5000K gemessen und berechnet.
https://doi.org/10.1515/teme-2017-0082
Schnelle Lufttemperaturfühler zur Anwendung in der Präzisionsmesstechnik und Maschinenkalibrierung. - In: Technisches Messen, ISSN 2196-7113, Bd. 85 (2018), 1, S. 70-75
https://doi.org/10.1515/teme-2017-0103
Low-field NMR relaxation times distributions and their magnetic field dependence as a possible biomarker in cartilage. - In: EMBEC & NBC 2017, (2018), S. 952-955
https://doi.org/10.1007/978-981-10-5122-7_238
Automatisierte Detektion von verschmolzenen Wolframkarbiden für die Charakterisierung des Schweißprozesses :
Automatic detection of fused tungsten carbides for the characterization of welding process. - In: Technisches Messen, ISSN 2196-7113, Bd. 85 (2018), 3, S. 159-166
https://doi.org/10.1515/teme-2017-0052
Neuartiges monolithisches Tiltmeter mit Nanorad Auflösung :
Novel monolithic pendulum tiltmeter with nanorad resolution. - In: Technisches Messen, ISSN 2196-7113, Bd. 85 (2018), 4, S. 244-251
Tiltmeters with nanorad resolution in a large measurement range of ±9 mrad (±0.5˚) and a very good linearity have been developed at the Technische Universität Ilmenau in the recent years. The working principle bases on the measurement of tilt-dependent lateral forces, which act on a hanging force-compensated weigh cell (precision balance). The disadvantage is the relatively complex design of the weigh cell mechanics, the large dead weight and the high manufacturing costs. - For that reason a simplified tiltmeter was developed. It only consists of two components: a monolithic pendulum mechanics and an optical position sensor. State of the art pendulum tiltmeters contain several components that are linked by screwed, clamped or glued connections. This can limit the long-term-, temperature- or humidity stability of the tiltmeter. - The position sensor achieves a standard deviation of ˜50 pm at a measuring frequency of 10 Hz. The length of the pendulum amounts to 0.1 m, its mass is ˜62 g. With this combination, the theoretical standard deviation of the tilt measurement should result to ˜0.6 nrad at 10 Hz measuring frequency and was approved by measurements. The measurement range of the new monolithic tiltmeter amounts ˜±2 mrad.
https://doi.org/10.1515/teme-2017-0097
Convective heat transfer in engine coolers influenced by electromagnetic fields. - In: Heat and mass transfer, ISSN 1432-1181, Bd. 54 (2018), 8, S. 2599-2605
In engine coolers of off-highway vehicles, convec- tive heat transfer at the coolant side limits both efficiency and performance density of the apparatus. Here, due to restrictions in construction and design, backwater areas and stagnation regions cannot be avoided. Those unwanted changes in flow characteristics are mainly triggered by flow deflections and sudden cross-sectional expansions. In application, mixtures of water and glysantine are used as appropriate coolants. Such coolants typically show an electrical conductivity of a few S/m. Coolant flow and convective heat transfer can then be controlled using Lorentz forces. These body forces are generated within the conducting fluid by the interactions of an electrical current density and a localized magnetic field, both of which are externally superimposed. In future applica- tion, this could be achieved by inserting electrodes in the cooler wall and a corresponding arrangement of permanent magnets. In this paper we perform numerical simulations of such magnetohydrodynamic flow in three model geometries that frequently appear in engine cooling applications: Carnot- Borda diffusor, 90˚ bend, and 180˚ bend. The simulations are carried out using the software package ANSYS Fluent. The present study demonstrates that, depending on the electromag- netic interaction parameter and the specific geometric arrange- ment of electrodes and magnetic field, Lorentz forces are suit- able to break up eddy waters and separation zones and thus significantly increase convective heat transfer in these areas. Furthermore, the results show that hydraulic pressure losses can be reduced due to the pumping action of the Lorentz forces.
https://doi.org/10.1007/s00231-017-2130-4