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Naveen Margankunte

Publications and source records attributed to Naveen Margankunte.

2 recordsLinked to original sources

Multi-Modal Super Resolution for Dense Microscopic Particle Size Estimation

Particle Size Analysis (PSA) is an important process carried out in a number of industries, which can significantly influence the properties of the final product. A ubiquitous instrument for this purpose is the Optical Microscope (OM). However, OMs are often prone to drawbacks like low resolution, small focal depth, and edge features being masked due to diffraction. We propose a powerful application of a combination of two Conditional Generative Adversarial Networks (cGANs) that Super Resolve OM images to look like Scanning Electron Microscope (SEM) images. We further demonstrate the use of a custom object detection module that can perform efficient PSA of the super-resolved particles on both, densely and sparsely packed images. The PSA results obtained from the super-resolved images have been benchmarked against human annotators, and results obtained from the corresponding SEM images. The proposed models show a generalizable way of multi-modal image translation and super-resolution for accurate particle size estimation.

eess.IV

Temperature evolution of polaron dynamics and Jahn-Teller distortion modes in strongly correlated La$_{0.67}$Ca$_{0.33}$MnO$_{3}$ manganite film

Reflectivity as a function of temperature for the La$_{0.67}$Ca$_{0.33}$MnO$_{3}$ (LCMO) film has been measured across the metal-insulator phase transition. The optical properties and their temperature dependence were determined in the infrared and visible range by fits to a Drude-Lorentz model, using exact formula for the thin film optics and the measured properties of the substrate. The phonon modes were identified and verified with lattice dynamical calculations for the ideal and distorted perovskite structure of the material. The optical conductivity shows agreement with the double exchange mechanism in conjunction with the Jahn-Teller distortion term in the Hamiltonian. Low temperature metallic phase is dominated by large polaron dynamics, a key component of electron-orbital coupling in a strongly corrrelated system. Free carrier dynamics in the metallic phase is described in terms of coherent heavy polaronic motion in the DC limit with incoherent and asymmetric polaronic background in the mid-IR range. The strength and line width of Jahn-Teller modes has been discussed across the phase transition and their temperature evolution is qualitatively discussed on account of existing electron-phonon coupling. The localized Holstein polaron formation in the high temperature insulative phase is identified as optical conductivity peaks in the visible range above the critical temperature.

cond-mat.str-el