Collection optimization of photo-generated charge carriers for efficient organic solar cells. - In: Journal of power sources, ISSN 1873-2755, Bd. 412 (2019), S. 465-471
https://doi.org/10.1016/j.jpowsour.2018.11.063
Mathematical modeling of friction stir welding considering dry and viscous friction. - In: Applied mathematical modelling, Bd. 67 (2019), S. 1-8
Corrigendum: Bd. 77 (2020), part 1, page 981
https://doi.org/10.1016/j.apm.2018.10.014
Charge transport in GaAs nanowires: interplay between conductivity through the interior and surface conductivity. - In: Journal of physics, ISSN 1361-648X, Bd. 31 (2019), 7, 074004, insges. 7 S.
https://doi.org/10.1088/1361-648X/aaf515
Exciting vibrons in both frontier orbitals of a single hydrocarbon molecule on graphene. - In: Journal of physics, ISSN 1361-648X, Bd. 31 (2019), 6, S. 065001, insges. 9 S.
https://doi.org/10.1088/1361-648X/aaf54c
Optimizing hydrogen evolution activity of nanoporous electrodes by dual-step surface engineering. - In: Applied catalysis, ISSN 1873-3883, Bd. 244 (2019), S. 87-95
https://doi.org/10.1016/j.apcatb.2018.11.036
Enhancing potassium-ion battery performance by defect and interlayer engineering. - In: Nanoscale horizons, ISSN 2055-6764, Bd. 4 (2019), 1, S. 202-207
Defect and interlayer engineering is applied to exploit the large van der Waals gaps of transition metal dichalcogenides for potassium-ion batteries (KIBs). As a demonstrator, MoS2 nanoflowers with expanded interlayer spacing and defects in the basal planes are used as KIB anodes in the voltage range of 0.5–2.5 V, where an intercalation reaction rather than a conversion reaction takes place to store K-ions in the van der Waals gaps. The nanoflowers show enhanced K-storage performance compared to the defect-free counterpart that has a pristine interlayer spacing. Kinetic analysis verifies that the K-ion diffusion coefficient and surface charge storage are both enhanced in the applied voltage range of the intercalation reaction. The collective effects of expanded interlayer spacing and additionally exposed edges induced by the in-plane defects enable facile K-ion intercalation, rapid K-ion transport and promoted surface K-ion adsorption simultaneously.
https://doi.org/10.1039/C8NH00305J
Thermocapillary convection during hydrogen evolution at microelectrodes. - In: Electrochimica acta, ISSN 1873-3859, Bd. 297 (2019), S. 929-940
The origin of strong electrolyte flow during water electrolysis is investigated, that arises at the interface between electrolyte and hydrogen bubbles evolving at microelectrodes. This Marangoni convection was unveiled only recently (Yang et al., PCCP, 2018, [1]) and is supposed to be driven by shear stress at the gas-liquid interface caused by thermal and concentration gradients. The present work firstly allows a quantification of the thermocapillary effect and discusses further contributions to the Marangoni convection which may arise also from the electrocapillary effect. Hydrogen gas bubbles were electrolytically generated at a horizontal Pt microelectrode in a 1MH2SO4 solution. Simultaneous measurements of the velocity and the temperature field of the electrolyte close to the bubble interface were performed by means of particle tracking velocimetry and luminescent lifetime imaging. Additionally, corresponding numerical simulations of the temperature distribution in the cell and the electrolyte flow resulting from thermocapillary stress only were performed. The results confirm significant Ohmic heating near the micro-electrode and a strong flow driven along the interface away from the microelectrode. The results further show an excellent match between simulation and experiment for both the velocity and the temperature field within the wedge-like electrolyte volume at the bubble foot close to the electrode, thus indicating the thermocapillary effect as the major driving mechanism of the convection. Further away from the microelectrode, but still below the bubble equator, however, quantitative differences between experiment and simulation appear in the velocity field, whereas the temperature gradient still matches well. Thus, additional effects must act on the interface, which are not yet included in the present simulation. The detailed discussion tends to rule out solution-based effects, generally referred to as solutal effects, whereas electrocapillary effects are likely to play a role. Finally, the thermocapillary effect is found to exert a force on the bubble which is retarding its departure from the electrode.
https://doi.org/10.1016/j.electacta.2018.11.187
Using normal probability plots to determine parameters for higher-level factorial experiments with orthogonal and orthonormal bases. - In: The Canadian journal of chemical engineering, ISSN 1939-019X, Bd. 97 (2019), 1, S. 152-164
In chemical engineering applications such as optimizing plant operations and product quality, factorial experiments are often conducted to obtain empirical models for systems. While the mathematical underpinning for two-level factorial designs is well understood, a methodology for analyzing higher-level experiments is not readily available. Often an orthogonal or orthonormal basis is selected for a factorial design matrix. In factorial design, an orthonormal basis is defined as an orthogonal matrix where the Euclidean two-norms of the column vectors are equal. This investigation examines, for full factorial design, the selection of parameters using normal probability plots and the effect that the design basis has on parameter determination. When using normal probability plots to determine parameter significance, the traditional orthogonal basis for higher-level experiments may result in erroneous conclusions. A Monte-Carlo experiment was developed to simulate 3-level and mixed-level factorial experiments with different types of measurement error. The basis chosen is shown to affect the shape of probability plots, and measurement errors from a given normal distribution are shown to result in a constant standard deviation for all parameter estimates only when using an orthonormal basis.
https://doi.org/10.1002/cjce.23296
Cost-sensitive large margin distribution machine for fault detection of wind turbines. - In: Cluster computing, ISSN 1573-7543, Bd. 22 (2019), S. S7525-S7537
https://doi.org/10.1007/s10586-018-1854-3
Bleaching effects and fluorescence lifetime imaging ophthalmoscopy. - In: Biomedical optics express, ISSN 2156-7085, Bd. 10 (2019), 3, S. 1446-1461
https://doi.org/10.1364/BOE.10.001446