ABSTRACT
While it has been demonstrated that, above its resolution limit, Second Harmonic Generation (SHG) microscopy can map chiral local field enhancements, below that limit, structural defects were found to play a major role. Here we show that, even below the resolution limit, the contributions from chiral local field enhancements to the SHG signal can dominate over those by structural defects. We report highly homogeneous SHG micrographs of star-shaped gold nanostructures, where the SHG circular dichroism effect is clearly visible from virtually every single nanostructure. Most likely, size and geometry determine the dominant contributions to the SHG signal in nanostructured systems.
Subject(s)
Algorithms , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Microscopy/methods , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
In activated sludge wastewater treatment research, most of the attention has been devoted to the biodegradation process. However, in terms of effluent quality, the final settling and clarification processes are at least as important because any particle carried over the overflow weir brings with it not only COD, but also nitrogen and phosphorus. In recent years we see indeed increased attention on this separation step, and alternatives such as membrane separation are increasingly introduced. Still, a large installed base of settlers exists, whose operation could/should be optimised. The measurement techniques presented in this contribution each focus on one of the key processes in the secondary settler: hydrodynamics, particle aggregation and breakage, hindered settling and compression. For each technique, the measuring principle is explained and a typical data set shown.
