NachhaltigElektrotechnik und MedientechnikIQMAZeitschriftenartikel
H. Fan, Y. Zhang, D. Liu, C. Niu, L. Liu, W. Ni, Y. Xia, Z. Bi, Günther Benstetter, G. Lei
Tensile stress-driven cracking of W fuzz over W crystal under fusion-relevant He ion irradiations
Nuclear Fusion, vol. 60, no. 4
DOI: 10.1088/1741-4326/ab71bb
Abstract anzeigen
Although W fuzz is formed in the divertor region of the fusion reactor, no theory may clearly explain the W fuzz growth mechanism. In this study, we observe the growth process of W fuzz over W crystal under ITER-relevant He ion irradiations. We propose the tensile stress-driven cracking of nano-structured fuzz during the initial growth of W fuzz. We demonstrate that the existence of tensile stress is due to the swelling of He nano-bubbles in the fuzz. After this cracking, the W fuzz breaks away from the planar network and grows over the W surface, where the micro-stress in the W surface layer acts as the driving force.
Elektrotechnik und MedientechnikZeitschriftenartikel
H. Heckelmüller, F. Kendl, Gerhard Krump
TDR Einzahlwert zur Charakterisierung der dynamischen Oberbausteifigkeit
ZEVrail - Zeitschrift für das gesamte System Bahn, vol. 144, no. Mai, pp. 190-194
Abstract anzeigen
Der Schallmesswagen (SMW) der DB Systemtechnik prüft den akustischen Zustand des Oberbaus und wird vor allem zur Überprüfung von Streckenabschnitten mit der Maßnahme „Besonders überwachtes Gleis“ (BüG) verwendet. Zusätzlich wird der SMW zur Qualitätskontrolle und Abnahme des akustischen Schienenschleifens eingesetzt. Falls ein BüG-Abschnitt nicht vom SMW befahren werden kann, gilt seit 2001 die Ersatzmaßnahme RMF-BüG. Dieses Verfahren soll die Messaufgaben des SMW durch kontinuierliche Rauheitsmessungen beider Schienen ersatzweise übernehmen können. Beim RMF-BüG-Verfahren wurde zur Berechnung des SMW-Pegels ausschließlich die Schienenrauheit berücksichtigt. Anhand einer Vielzahl von Messungen konnte gezeigt werden, dass das Rollgeräusch des SMW signifikant ebenfalls von der Gleisabklingrate (Track Decay Rate TDR) abhängig ist. Das vorgestellte Verfahren zeigt die Verwendung des Einzahlwertes der Schienenrauheit LλCA und des Einzahlwertes der TDR L TDR zur Bestimmung des SMW-Pegels.
NachhaltigElektrotechnik und MedientechnikIQMAZeitschriftenartikel
Z. Bi, D. Liu, Y. Zhang, L. Liu, Y. Xia, Y. Hong, H. Fan, Günther Benstetter, G. Lei, L. Yan
The evolution of He nanobubbles in tungsten under fusion-relevant He ion irradiation conditions
Nuclear Fusion, vol. 59, no. 8
DOI: 10.1088/1741-4326/ab2472
Abstract anzeigen
He-induced W nanofuzz growth over the W divertor target is one of the main limiting factors affecting the current design and development of fusion reactors. In this paper, based on He reaction rate model in W, we simulate the growth and evolution of He nanobubbles during W nanofuzz formation under fusion-relevant He+ irradiation conditions. Our modeling unveils the existence of He nanobubble-enriched W surface layer (<10 nm), formed due to the He diffusion in W crystal into defect sites. At an elevated temperature, the growth of He bubbles in the W surface layer prevents He atoms diffusing into the deep layer (>10 nm). The formation of W nanofuzz at the surface is attributed to surface bursting of high-density He bubbles with their radius of ~4 nm, and an increase in the surface area of irradiated W. Our findings have been well confirmed by the experimental measurements.
NachhaltigElektrotechnik und MedientechnikIQMAZeitschriftenartikel
Christoph Metzke, Werner Frammelsberger, Jonas Weber, Fabian Kühnel, K. Zhu, M. Lanza, Günther Benstetter
On the Limits of Scanning Thermal Microscopy of Ultrathin Films
Materials, vol. 13, no. 3
DOI: 10.3390/ma13030518
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Heat transfer processes in micro- and nanoscale devices have become more and more important during the last decades. Scanning thermal microscopy (SThM) is an atomic force microscopy (AFM) based method for analyzing local thermal conductivities of layers with thicknesses in the range of several nm to µm. In this work, we investigate ultrathin films of hexagonal boron nitride (h-BN), copper iodide in zincblende structure (γ-CuI) and some test sample structures fabricated of silicon (Si) and silicon dioxide (SiO2) using SThM. Specifically, we analyze and discuss the influence of the sample topography, the touching angle between probe tip and sample, and the probe tip temperature on the acquired results. In essence, our findings indicate that SThM measurements include artefacts that are not associated with the thermal properties of the film under investigation. We discuss possible ways of influence, as well as the magnitudes involved. Furthermore, we suggest necessary measuring conditions that make qualitative SThM measurements of ultrathin films of h-BN with thicknesses at or below 23 nm possible.
NachhaltigElektrotechnik und MedientechnikIQMAZeitschriftenartikel
W. Ni, L. Liu, Y. Zhang, C. Niu, H. Fan, G. Song, D. Liu, Günther Benstetter, G. Lei
Effect of intermittent He/D ion irradiations on W nano-fuzz growth over W targets
Vacuum, vol. 173, no. March
DOI: 10.1016/j.vacuum.2019.109146
Abstract anzeigen
The intermittent He/D ion irradiations of polycrystalline W have been performed at the ion energy of 50 eV by changing the time of the single irradiations and the irradiation temperature. All irradiated W specimens have been observed by scanning electron microscopy, and the effect of intermittent He/D ion irradiations on the W fuzz growth has been analyzed. The W fuzz growth over W targets does not show the clear dependence on the intermittent He/D ion irradiations, where the He/D ion fluence of the single irradiations typically varies from 5.0 × 1024 to 2.5 × 1025/m2. However, a slight change in the W surface temperature during the single He ion irradiations significantly affects the W fuzz growth rate. Analysis indicates that W fuzz growth is significantly affected by the total He ion fluence varying from 5.0 × 1024 to 5.0 × 1025/m2 and the irradiation temperature varying from 1100 to 1450 K. This current study will play a crucial role in understanding the W fuzz growth under the periodic He/D ion irradiations of W divertor in fusion reactors, such as ELMs.
NachhaltigElektrotechnik und MedientechnikIQMAZeitschriftenartikel
W. Ni, L. Liu, Y. Zhang, H. Fan, G. Song, D. Liu, Günther Benstetter, G. Lei
Mass loss of pure W, W-Re alloys, and oxide dispersed W under ITER-relevant He ion irradiations
Journal of Nuclear Materials, vol. 527
DOI: 10.1016/j.jnucmat.2019.151800
Abstract anzeigen
In this study, polycrystalline W, W-Re alloys, and La2O3 and Y2O3 dispersion-strengthened W have been irradiated by our large-power materials irradiation experimental system (LP-MIES) at the irradiation temperature of 1360–1460 K. Our measurements show that the W nano-fuzz layer which is < 5.2 μm thick has been formed over all the specimens exposed to the low-energy (50 or 100 eV) and high-flux (1.37 × 1022–1.62 × 1022 ions/m2⋅s) He+ irradiations. The mass loss of the fuzz layer almost linearly increases with the He+ fluence, which does not show any dependence on the thickness of fuzz layer varying from 1.1 to 5.2 μm La2O3 and Y2O3 dispersions into W significantly suppress the growth of W fuzz, indicating that He diffusion and the evolution of He nano-bubbles in the near-surface can be significantly influenced due to the dispersion. After He+ (100 eV) irradiation at He+ fluence of 5.83 × 1026/m2, the mass loss of 0.1 vol% - 1.0 vol% La2O3-dispersed W is about 20% lower than the one of the pure W, and the La2O3 dispersed W exhibits the best erosion resistance among various W material grades. Our analysis indicates that both the surface sputtering of W fuzz by energetic ions and surface bursting of He nano-bubbles can be responsible for the mass loss of W under ITER-relevant He+ irradiations.
NachhaltigElektrotechnik und MedientechnikIQMAZeitschriftenartikel
C. Wen, X. Jing, F. Hitzel, C. Pan, Günther Benstetter, M. Lanza
In Situ Observation of Current Generation in ZnO Nanowire Based Nanogenerators Using a CAFM Integrated into an SEM
ACS Applied Materials & Interfaces, vol. 11, no. 17, pp. 15183-15188
DOI: 10.1021/acsami.9b00447
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In this work, we monitor in situ the movement of ZnO piezoelectric nanowires by using a conductive atomic force microscope integrated into a scanning electron microscope. This setup allows seeing the bending of the nanowires and simultaneously measuring the currents generated. We conclude that the currents generated not only come from piezoelectric effect, but also from contact potential and triboelectric effect. These contributions have been ignored in all previous reports in this field, meaning that the power conversion efficiency of these devices may have been systematically overestimated. Our study helps to clarify the working mechanism of piezoelectric nanogenerators based on ZnO nanowires.
DigitalElektrotechnik und MedientechnikBeitrag (Sammelband oder Tagungsband)
László Juhász, Amir Samiee, W. Engelbrecht
XCP Service Integration for Model-Based, Automatic Production Code Generation
Proceedings of IEEE EUROCON 2019 -18th International Conference on Smart Technologies
DOI: 10.1109/EUROCON.2019.8861774
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Automated, model-based production code generation is widely used in the development and testing of electronic control units (ECUs). During ECU commissioning, extensive tests of the implemented control algorithms are required. Knowledge of the internal values and states of the ECU software are essential for verifying the correct software functionality by means of complex control algorithms. Calibration and measurement services make it possible to observe the ECU-internal memory values associated with the variables originating from the function model. Furthermore, the final adjustment of control parameters in the production ECU can be performed by means of calibration services. For these reasons, calibration and measurement through service integration is widely applied in both the automotive industry and other industrial fields. Integrating measurement and calibration services is therefore an important task for engineers working with model-based control development and, particularly, ECU production code integration. This paper describes an example integration of the Universal Measurement and Calibration Protocol (XCP) for model-based automatic code generation. The application used for the service integration is the commercially available Motor Control Education Kit (MEDKit) from Emerge-Engineering and dSPACE GmbH. The model-based automatic code generation is performed using the production code generator dSPACE TargetLink. The integration of the XCP on CAN protocol is completed in the scope of student projects. The upgraded MEDKit demonstrator will be used for education purposes in the Deggendorf Institute of Technology.
DigitalNachhaltigElektrotechnik und MedientechnikInstitut ProtectITBeitrag (Sammelband oder Tagungsband)
Michael Heigl, Laurin Dörr, Martin Schramm, D. Fiala
On the Energy Consumption of Quantum-resistant Cryptographic Software Implementations Suitable for Wireless Sensor Networks
Proceedings of the 16th International Joint Conference on e-Business and Telecommunications (July 26-28, 2019; Prague, Czech Republic), vol. Vol. 2 (SECRYPT 2019 : 16th International Conference on Security and Cryptography)
DOI: 10.5220/0007835600720083
Abstract anzeigen
For an effective protection of the communication in Wireless Sensor Networks (WSN) facing e.g. threats by quantum computers in the near future, it is necessary to examine the applicability of quantum-resistant mechanisms in this field. It is the aim of this article to survey possible candidate schemes utilizable on sensor nodes and to compare the energy consumption of a selection of freely-available software implementations using a WSN-ready Texas Instruments CC1350 LaunchPad ARM® Cortex®-M3 microcontroller board.
Version: 2.1.2-qf2