Fig. 1 Schematic of 5D-STEM79Poster Award NomineeP4-15Poster Award NomineeObservation Conditions for Grayscale HREM Image Interpretation via Persistent Homology Ankit Singh1, Ryuto Eguchi1,2, Kazutaka Mitsuishi3 and Ayako Hashimoto1,2 1 Research Center for Energy and Environmental Materials, National Institute for Materials Science (NIMS) 2 Graduate School of Science and Technology, University of Tsukuba 3 Center for Basic Research on Materials, National Institute for Materials Science (NIMS) Persistent Homology (PH) is a mathematical tool that quantifies topological features like ‘holes’ by recording their ‘birth’ and ‘death’ in a persistent diagram (PD). PH is widely used in materials science for complex systems and recently applied to grayscale image analysis for structural patterns [1]. The accuracy of PH in interpreting structural patterns from grayscale images, particularly via High-Resolution Electron Microscopy (HREM), depends heavily on the imaging conditions. This study investigates the optimal observation conditions to minimize inaccuracy in structural pattern interpretation in HREM images. The images are based on a molecular-dynamics simulated model of amorphous carbon. Our findings reveal how observation parameters like defocus, sample thickness, and orientation affect PH’s effectiveness in analyzing grayscale HREM images. [1] Fumihiko Uesugi, and Masashi Ishii, Microscopy, 71(3), 161-168 (2022). P4-16Development of 5-dimensional STEM and Application to Glass Transition PhenomenonKatsuaki Nakazawa1, Kazutaka Mitsuishi2 , Shinji Kohara2, and Koichi Tsuchiya1,31 International Center for Young Scientists, National Institute for Materials Science (NIMS) 2 Center for Basic Research on Materials, National Institute for Materials Science (NIMS) 3 Research Center for Structural Materials, National Institute for Materials Science (NIMS) In recent years, the development of high-speed pixelated scanning transmission electron microscope (STEM) detectors has made it easier to perform 4-dimensional STEM [1], which allows for the acquisition of spatial distributions of diffraction patterns.We further advanced this technique to enable continuous observations using 4D-STEM, making it possible to acquire the spatiotemporal distribution of diffraction patterns. We call this method 5D-STEM since the time dimension is added to the conventional 4D-STEM [2]. In this study, we applied the developed 5D-STEM method to investigate the glass transition phenomenon in metallic glass. A correlation between local dynamics and atomic structures was revealed, which indicates that area with less-ordered structures tends to exhibit a shorter relaxation time.[1] C. Ophus, Microscopy and Microanalysis, 25, 563-582 (2019).[2] K. Nakazawa and K. Mitsuishi, Microscopy, 72, 446-449 (2023).
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