We used a combination of Raman microscopy, AFM and TEM to quantify the influence of dimerization on the surface enhanced Raman spectroscopy (SERS) signal for gold and silver nanoparticles (NPs) modified with Raman reporters and situated on gold, silver, and aluminum films and a silicon wafer. The overall increases in the mean SERS enhancement factor (EF) upon dimerization (up by 43% on average) and trimerisation (up by 96% on average) of AuNPs and AgNPs on the studied metal films are within a factor of two, which is moderate when compared to most theoretical models. However, the maximum ratio of EFs for some dimers to the mean EF of monomers can be as high as 5.5 for AgNPs on a gold substrate. In contrast, for dimerization and trimerization of gold and silver NPs on silicon, the mean EF increases by 1-2 orders of magnitude relative to the mean EF of single NPs. Therefore, hot spots in the interparticle gap between gold nanoparticles rather than hot spots between Au nanoparticles and the substrate dominate SERS enhancement for dimers and trimers on a silicon substrate. However, Raman labeled noble metal nanoparticles on plasmonic metal films generate on average SERS enhancement of the same order of magnitude for both types of hot spot zones (e.g. NP/NP and NP/metal film).

Raman and Brillouin spectroscopies enable noninvasive assessment of chemical and elastic properties of biomaterials, respectively. In this report, Brillouin microspectroscopy was used for the time‐resolved analysis of elastic properties of Populus and Geranium leaves, whereas Raman microspectroscopy was employed for the assessment of their chemical variation during drying. Spectroscopic assessment of elastic and chemical properties can improve our understanding of mechanochemical changes of plants in response to environmental stress and pathogens at the microscopic cellular level. This report demonstrates the potential of multimodal optical sensing and imaging of plants as an emerging technique for the quantitative assessment of agricultural crops.

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Mitigation of corona discharge is fundamental problem that was formulated by Lord Kelvin in 1911 but has not yet received a proper technical solution. On HVAC transmission lines up to 30% of the total electric power losses accounted for corona discharge (CD). A peak of losses occurs during adverse (wet) weather conditions, such as rain and snow. Coating on the surface of aluminium wire using microarc oxidation (MAO), also known as electrolytic plasma oxidation (EPO) was implemented to reduce losses due to CD. Samples covered by the surface with porous high-temperature α-Al2O3 aluminium oxide, silicon oxide SiO2, silicon carbide SiC reinforced with graphene oxide and carbon nanotubes. Industrial high-voltage testing shows that the significant reduction of the power loss due to corona of 30-50% has been measured in the present work where wires were coated with strong, adhesive, and super-hydrophilic layer. The corona ignition threshold voltage increased up to 40% in the rain conditions, and up to 15% for dry conditions. Simulations using finite element method (FEM) have shown a significant dependence of a local electric field enhancement factor on the surface wettability (hydrophilicity). Highly porous and hygroscopic properties of newly engineered surfaces allow to control contact angle of a water droplet on the wire and reduce the field enhancement factor in comparison with a uncoated surface via the effect of dielectric shielding.