NachhaltigElektrotechnik und MedientechnikIQMAZeitschriftenartikel
L. Liu, S. Li, D. Liu, Günther Benstetter, Y. Zhang, Y. Hong, H. Fan, W. Ni, Q. Yang, Y. Wu, Z. Bi
Surface damages of polycrystalline W and La2O3-doped W induced by high-flux He plasma irradiation
Journal of Nuclear Materials, vol. 501, no. April, pp. 275-281
2018
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In this study, polycrystalline tungsten (W) and three oxide dispersed strengthened W with 0.1 vol %, 1.0 vol % and 5.0 vol % lanthanum trioxide (La2O3) were irradiated with low-energy (200 eV) and high-flux (5.8 × 1021 or 1.4 × 1022 ions/m2⋅s) He+ ions at elevated temperature. After He+ irradiation at a fluence of 3.0 × 1025/m2, their surface damages were observed by scanning electron microscopy, energy dispersive spectroscopy, scanning electron microscopy-electron backscatter diffraction, and conductive atomic force microscopy. Micron-sized holes were formed on the surface of W alloys after He+ irradiation at 1100 K. Analysis shows that the La2O3 grains doped in W were sputtered preferentially by the high-flux He+ ions when compared with the W grains. For irradiation at 1550 K, W nano-fuzz was formed at the surfaces of both polycrystalline W and La2O3-doped W. The thickness of the fuzz layers formed at the surface of La2O3-doped W is 40% lower than the one of polycrystalline W. The presence of La2O3 could suppress the diffusion and coalescence of He atoms inside W, which plays an important role in the growth of nanostructures fuzz.
Hochschulleitung und -einrichtungenZeitschriftenartikel
Gregor Jaburek
Rechtsfragen besonderer Leistungsbezüge von Professoren
Zeitschrift für Beamtenrecht (ZBR) - Fachzeitschrift für das Beamtenrecht und das öffentliche Dienstrecht, no. im Erscheinen
2018
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenZeitschriftenartikel
Thomas Stirner, David Scholz, J. Sun
Ab initio simulation of structure and surface energy of low-index surfaces of stoichiometric alpha-Fe2O3
Surface Science, vol. 671, no. May, pp. 11-16
2018
DOI: 10.1016/j.susc.2018.01.010
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The structure and surface energy of a series of low-index surfaces of stoichiometric α-Fe2O3 (hematite) are investigated using the periodic Hartree–Fock approach with an a posteriori correction of the correlation energy. The simulations show that, amongst the modeled facets, (012) and (0001) are the most stable surfaces of hematite, which is consistent with the fact that the latter are the dominant growth faces exposed on natural α-Fe2O3. The Fe-terminated (0001) surface is shown to exhibit a large relaxation of the surface atoms. It is argued that this arises mainly due to the fact that the surface cations are located opposite empty cation sites in the filled-filled-unfilled cation sequence along the c-axis. In contrast, the (012) plane cuts the crystal through a plane of empty cation sites, thus giving rise to relatively small relaxations and surface energies. The small relaxations and concomitant exposure of five-coordinate cation sites may be important for the catalytic activity of hematite. The simulations also show that the relative stability of the investigated surfaces changes after a full lattice relaxation with the (0001) and (116) facets relaxing disproportionately large. Wherever possible, the simulations are compared with previous simulation data and experimental results. A Wulff–Gibbs construction is also presented.
Angewandte WirtschaftswissenschaftenSonstiges
Georg Herde
14. Deggendorfer Forum zur digitalen Datenanalyse - an der TH Deggendorf unter dem Motto: "Die Welt ist komplex: Verstehen Computer sie besser?" von 26.-27.04.2018 (Gestaltung und Leitung Prof. Dr. Georg Herde; In Kooperation mit audicon GmbH, Düsseldorf; BDO AG, Hamburg; DATEV e.G., Nürnberg)
2018
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenZeitschriftenartikel
O. Fähnle, Rolf Rascher, Christian Vogt, D.W. Kim
Closed-loop laser polishing using in-process surface finish metrology
Applied Optics, vol. 57, no. 4, pp. 834-838
2018
DOI: 10.1364/AO.57.000834
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This paper lays out the trail onto a closed-loop polishing process of optical elements enabling the application of the optimum polishing time needed. To that aim, an in-process testing method for monitoring an inclusive micro surface quality (e.g., comprising surface roughness and scratch-and-dig) within the polishing spot is analyzed and its applicability to closed-loop polishing for classical loose-abrasive full-aperture polishing as well as for computer controlled laser polishing is experimentally tested and verified. This enables the determination of the optimum local dwell time resulting in a stable and cost optimized polishing.
MobilAngewandte Naturwissenschaften und WirtschaftsingenieurwesenZeitschriftenartikel
A.-K. Rothenbächer, Michael Drexl, S. Irnich
Branch-and-Price-and-Cut for the Truck-and-Trailer Routing Problem with Time Windows
Transportation Science, vol. 52, no. 5, pp. 1174-1190
2018
DOI: 10.1287/trsc.2017.0765
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In this paper, we present a new branch-and-price-and-cut algorithm to solve the truck-and-trailer routing problem with time windows (TTRPTW) and two real-world extensions. In all TTRPTW variants, the fleet consists of one or more trucks that may attach a trailer. Some customers are not accessible with a truck-and-trailer combination, but can however be serviced by one if the trailer is previously detached and parked at a suitable location. In the first extension, the planning horizon comprises two days and customers may be visited either on both days or only once, in which case twice the daily supply must be collected. The second extension incorporates load transfer times depending on the quantity moved from a truck to its trailer. The exact branch-and-price-and-cut algorithm for the standard variant and the two new extensions is based on a set-partitioning formulation in which columns are routes describing the movement of a truck and its associated trailer. Linear relaxations of this formulation are solved by column generation where new routes are generated with a dynamic programming labeling algorithm. The effectiveness of this pricing procedure can be attributed to the adaptation of techniques such as bidirectional labeling, the ng-neighborhood, and heuristic pricing using dynamically reduced networks and relaxed dominance. The cutting component of the branch-and-price-and-cut adds violated subset-row inequalities to strengthen the linear relaxation. Computational studies show that our algorithm outperforms existing approaches on TTRP and TTRPTW benchmark instances used in the literature.
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