Taguchi method in experimental procedures focused on corrosion process of positive current collector in lithium-ion batteries. - In: Electrochimica acta, ISSN 1873-3859, Bd. 360 (2020), 137011
Planning the design and discussing the results are routine tasks carried out daily by researchers all over the world. This study is focused on making these stages of research time- and cost-efficient without affecting the reliability of the data. Following the principles of the Taguchi method brings such a result. This approach ensures the quality of research by optimisation of the experimental procedure. In the presented work, the Taguchi method solves an exemplary research problem of the corrosion process of aluminium current collector in lithium-ion batteries. Operating factors selected for the optimisation include temperature (25, 35, 45˚C), the volume ratio of ethylene carbonate to diethyl carbonate in the solvent (1:1, 1:2, 1:4), and type of lithium salt (LiPF6, LiTFSI, LiBOB). Using three operating factors with three levels of variability requires data assembly in an orthogonal array L9 with nine experimental runs in total. In this study, the Taguchi approach is validated by performing a full-factorial procedure of twenty-seven individual experiments. The response of tested systems is analysed by cyclic voltammetry and electrochemical impedance spectroscopy, which enables the evaluation of corrosion parameters in each experimental run. The assessed parameters indicate the intensity of the aluminium corrosion depending on the operating conditions. These conditions cause unwanted variance, which accelerates corrosion and lowers the life expectancy of lithium-ion batteries. The Taguchi signal-to-noise-ratio analysis reveals that the most significant variation is caused by the lithium salt in the electrolyte (S/N LiBOB ≥ LiPF6 > LiTFSI). Temperature and alkyl carbonates play a secondary role. The Taguchi prediction method is also consistent with the full-factorial approach, which warrants reliability.
https://doi.org/10.1016/j.electacta.2020.137011
Quantification of the As/P content in GaAsP during MOVPE growth. - In: Applied physics letters, ISSN 1077-3118, Bd. 117 (2020), 6, S. 061601-1-061601-5
Epitaxial integration of direct-bandgap III-V compound semiconductors with silicon requires overcoming a significant lattice mismatch. To this end, GaAsP step-graded buffer layers are commonly applied. The thickness and composition of the individual layers are decisive for the envisaged strain relaxation. We study GaAsP growth by metalorganic vapor phase epitaxy in situ with reflection anisotropy spectroscopy. We find that the growth surface exhibits optical fingerprints of atomically well-ordered surfaces. These allow for tuning the interface preparation between adjacent layers. The spectral position of the characteristic peaks in the RA spectra, which are related to surface-modified bulk transitions, behaves similarly upon an increased As content as does the E1 interband transition of GaAsP at the growth temperature. The impact of strain on this shift is negligible. We thus monitor a bulk property via the surface reconstruction. An empiric model enables quantification of the As content of individual layers directly in situ without growth interruptions and for various surface reconstructions. Our findings are suitable for a simplified optimization of the GaAsP buffer growth for high-efficiency devices.
https://doi.org/10.1063/5.0012948
Augmentation of absorption channels induced by wave-chaos effects in free-standing nanowire arrays. - In: Optics express, ISSN 1094-4087, Bd. 28 (2020), 16, S. 23569-23583
Plenty of issues on quantal features in chaotic systems have been raised since chaos was accepted as one of the intrinsic properties of nature. Through intensive studies, it was revealed that resonance spectra in chaotic systems exhibit complicated structures, which is deeply concerned with sophisticated resonance dynamics. Motivated by these phenomena, we investigate light absorption characteristics of chaotic nanowires in an array. According to our results, a chaotic cross-section of a nanowire induces a remarkable augmentation of absorption channels, that is, an increasing number of absorption modes leads to substantial light absorption enhancement, as the deformation of cross-section increases. We experimentally demonstrate the light absorption enhancement with free-standing Si-nanowire polydimethylsiloxane (PDMS) composites. Our results are applicable not only to transparent solar cells but also to complementary metal-oxide-semiconductor (CMOS) image sensors to maximize absorption efficiency.
https://doi.org/10.1364/OE.398687
eadf: representation of far-field antenna responses in Python. - In: SoftwareX, ISSN 2352-7110, Bd. 12 (2020), 100583, S. 1-6
https://doi.org/10.1016/j.softx.2020.100583
Water-soluble pristine C60 fullerene inhibits liver alterations associated with hepatocellular carcinoma in rat. - In: Pharmaceutics, ISSN 1999-4923, Bd. 12 (2020), 9, 794, S. 1-20
Richtiger Name des Verfassers: Eric Täuscher
https://doi.org/10.3390/pharmaceutics12090794
Comparison of algorithms to suppress artifacts from the natural lens in fluorescence lifetime imaging ophthalmoscopy (FLIO). - In: Biomedical optics express, ISSN 2156-7085, Bd. 11 (2020), 10, S. 5586-5602
https://doi.org/10.1364/BOE.400059
Feasibility study of using integrated fiber optical sensors to monitor laser-assisted metal-polymer joining. - In: Welding in the world, ISSN 1878-6669, Bd. 64 (2020), 9, S. 1565-1578
The possibilities and challenges of using fiber optical sensors to monitor the laser-assisted joining of metal-polymer joints have been described in this article. Fundamental investigation proves the basic suitability of the measuring method for this application and studies the effect of essential influencing variables of the joining process - e.g., the clamping force - on the resulting sensor signals. In addition, the strain state (because of the process temperature and shrinkage of the polymer) of the parts to be joined can be traced as a function of the joining partners, the process parameters, and the material thicknesses. It is shown that the fiber optical method is suitable for process monitoring directly in the joining zone of metal-polymer hybrids and providing a tool for detailed strain measurements in the joint zone during subsequent component testing.
https://doi.org/10.1007/s40194-020-00942-y
Revealing the local crystallinity of single silicon core-shell nanowires using tip-enhanced Raman spectroscopy. - In: Beilstein journal of nanotechnology, ISSN 2190-4286, Bd. 11 (2020), S. 1147-1156
https://doi.org/10.3762/bjnano.11.99
Scanning tunneling microscopy and spectroscopy of rubrene on clean and graphene-covered metal surfaces. - In: Beilstein journal of nanotechnology, ISSN 2190-4286, Bd. 11 (2020), S. 1157-1167
https://doi.org/10.3762/bjnano.11.100
Microbial community types and signature-like soil bacterial patterns from fortified prehistoric hills of Thuringia (Germany). - In: Community ecology, ISSN 1588-2756, Bd. 21 (2020), 2, S. 107-120
16S rRNA profiling has been applied for the investigation of bacterial communities of surface soil samples from forest-covered areas of ten prehistorical ramparts from different parts of Thuringia. Besides the majority bacterial types that are present in all samples, there could be identified bacteria that are highly abundant in some places and absent or low abundant in others. These differences are mainly related to the acidity of substrate and distinguish the communities of lime stone hills from soils of sand/quartzite and basalt hills. Minority components of bacterial communities show partially large differences that cannot be explained by the pH of the soil or incidental effects, only. They reflect certain relations between the communities of different places and could be regarded as a kind of signature-like patterns. Such relations had also been found in a comparison of the data from ramparts with formerly studied 16S rRNA profiling from an iron-age burial field. The observations are supporting the idea that a part of the components of bacterial communities from soil samples reflect their ecological history and can be understood as the "ecological memory" of a place. Probably such memory effects can date back to prehistoric times and might assist in future interpretations of archaeological findings on the prehistoric use of a place, on the one hand. On the other hand, the genetic profiling of soils of prehistoric places contributes to the evaluation of anthropogenic effects on the development of local soil bacterial diversity.
https://doi.org/10.1007/s42974-020-00017-4