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Aktuellste Veröffentlichungen
Item type:Item, Response preparation and the Simon effect: experimental and model-based analyses(2026-01-07) Heuer, Herbert; Wühr, PeterIn choice between frequent and infrequent responses the Simon effect is larger for the frequent than for the infrequent response. We arbitrate between three hypotheses to account for this finding. The first hypothesis holds that it is a straightforward consequence of biased response preparation. The second hypothesis posits a facilitation of the shift of visual attention to the side of the prepared response in addition, and the third one an effect of the different frequencies of congruent and incongruent trials associated with the task-irrelevant stimulus locations. In three experiments we show the modulation of the Simon effect by relative response frequency, its independence from the distance between hands and monitor, and its almost complete elimination by valid response cues. These findings are in line with a primary role of biased response preparation. Consistent with this conclusion, in a model-based analysis, using extensions of the Leaky, Competing Accumulator model, differences between the probabilities of preparing the frequent and infrequent response were sufficient to produce the modulation of the Simon effect, though only poorly its dynamics as assessed by delta plots. However, these dynamics were produced by a model which implemented the hypothesis that response preparation implicates shielding against distraction in addition to anticipatory response activation. According to simulation results, the modulation of congruency effects by relative response frequency might depend on the particular type of congruency effect, specifically the temporal offset between the impacts of relevant and irrelevant stimuli.Item type:Item, A [2.2]isoindolinophanyl-based carbene (iPC) ligand: synthesis, electronic and photophysical properties, and application in photocatalysis(2024-07-04) Maity, Sabyasachi; Muthig, André Martin Thomas; Sen, Indranil; Mrózek, Ondřej; Belyaev, Andrey; Hupp, Benjamin; Steffen, AndreasCyclic amino(alkyl) and cyclic amino(aryl) carbenes (cAACs/cAArCs) have been established as very useful ligands for catalytic and photonic applications of transition metal complexes. Herein, we describe the synthesis of a structurally related sterically demanding, electrophilic [2.2]isoindolinophanyl-based carbene (iPC) that bears a [2.2]paracyclophane moiety. The latter leads to more delocalized frontier orbitals and intense green fluorescence of (HiPC)OTf (2) from an intra-ligand charge transfer (1ILCT) state in the solid state. Base-promoted synthesis of the free carbene led to an unusual ring expansion and subsequent dimerization reaction, but the beneficial ligand properties can be exploited by trapping in situ at a metal center. The iPC ligand is a very potent π-chromophore, which participates in low energy metal-to-ligand (ML)CT transitions in [RhCl(CO)2(iPC)] (4) and IL-“through-space”-CT transitions in [Au(iPC)2]OTf (5). The steric demand of the iPC leads to high stability of 5 against air, moisture, or solvent attack, and ultralong-lived green phosphorescence with a lifetime of 185 μs is observed in solution. The beneficial photophysical and electronic properties of the iPC ligand, including a large accessible π surface area, were exploited by employing highly efficient energy transfer (EnT) photocatalysis in a [2+2] styrene cycloaddition reaction using 5, which outperformed other established photocatalysts in comparison.Item type:Item, Amtliche Mitteilungen der Technischen Universität Dortmund Nr. 12/2026(Technische Universität Dortmund, 2026-05-18)Item type:Item, Orientation-dependent stress evolution in diamond abrasive grains under directional loading(2026-04-29) Brune, Gabriel; Tsagkir Dereli, Tountzer; Olschewski, Lars; Lopes Dias, Nelson Filipe; Kipp, Monika; Biermann, Dirk; Debus, JörgUnderstanding the response of diamond abrasive grains to mechanical loading remains crucial for optimizing their performance in precision manufacturing. In that context, the role of the initial residual stress and crystallographic orientation of the grains is poorly understood. We investigate synthetic diamond grains in two different grit sizes (D126, D252) subjected to directional loading up to 100 N using x-ray diffraction and spatially resolved Raman spectroscopy. Small grains with preferential (111) orientation show an unexpected stress evolution under contact pressures up to 16 GPa, with Raman shifts increasing from 1331.3 to 1333.0cm−1, indicating an enhanced local compressive stress state at the probed surface regions. Conversely, large (311)-oriented grains exhibit a heterogeneous stress development with Raman shifts varying from 1331.5 to 1332.6cm−1, including regions that become more tensile (or less compressive) relative to their initial state. The relationship between the relative Raman shift and a spatially weighted contact pressure follows an empirical power law 𝛿𝐸∝𝑝′𝛼c with opposite, orientation-dependent exponents: 𝛼≈+0.25 for (111) grains showing progressive compression enhancement and 𝛼≈−0.35 for (311) grains exhibiting a trend toward tensile stress components with increasing load. Molecular dynamics simulations reveal that the Schmid factor governs this orientation-dependent response: The low Schmid factor (0.27) for [111] loading restricts dislocation glide, leading to stress retention with high elastic recovery, while the high Schmid factor (0.45) for [311] loading facilitates plastic flow and stress relaxation despite lower peak stress. These findings demonstrate that stress evolution in diamond under directional loading is controlled by the geometric relationship between loading direction and slip systems, providing mechanistic insights for diamond tool design.Item type:Item, From light pulses to selective enhancement: performance analysis of event-based object detection under pulsed automotive headlight illumination(2026-04-22) Haensel, Leonard; Bertram, TorstenPulse-width-modulated (PWM) automotive headlights enhance nighttime event-based camera detection, yet systematic parameter optimization for vulnerable road user detection remains unexplored. This study evaluates PWM frequency, duty cycle, light distribution, ego-vehicle speed, and ambient lighting under European New Car Assessment Programme-inspired crossing scenarios for cyclist and pedestrian detection. Results establish performance ranging from substantial improvements to severe degradation relative to continuous illumination. Cyclist detection achieves robust performance with high-frequency modulation across light distributions, while low-frequency operation with low beam produces severe degradation through background noise accumulation. Pedestrian detection requires high beam with street lighting enabled; low beam universally fails regardless of modulation parameters. Limited parameter combinations achieve simultaneous improvements for both targets. Detection performs optimally on retroreflective surfaces, while low-reflectivity clothing limits capability, requiring target-specific optimization.