435 research outputs found

    Mechanical Characterization of APA Microcapsules by Parallel-Plate Compression

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    We produced microcapsules of alginate-poly(L)lysine-alginate (APA)with diameters on the order of 10 µm. To characterize their mechanical properties, we conducted an experiment on the parallel-plate compression of a microcapsule and modeled its deformation. In the modeling task, the microcapsule was assumed to be a spherical liquid-filled elastic membrane with negligible bending stiffness and permeability. The membrane thickness was estimated by applying Reissner's linear elastic theory to the experimental force-displacement relationship during loading in the small displacement region. The initial stretch of the membrane was taken into account; it was mainly caused by the osmotic pressure difference across the membrane. The initial stretch of the microcapsule was determined by fitting the calculated and experimental force-displacement relationships during loading at small to medium displacements. At large displacements, the calculated force was smaller than the experimentally measured force because of fluid permeation across the APA membrane. The calculated and experimentally imaged shapes of the deformed microcapsule were compared. The effects of varying the membrane thickness on the force-displacement and transmural pressure-displacement curves were shown, and the limitations of applying the present deformation model were examined

    陽子・陽子衝突を用いたヒッグス粒子の二光子事象の観測

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    学位の種別:課程博士University of Tokyo(東京大学

    Raman Studies of Structural Changes in Diamond-like Carbon Films on Si Induced by Ultrafast Laser Ablation

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    In this study, the diamond-like carbon (DLC), a tetrahedral amorphous carbon sample deposited on Si, was irradiated using a picosecond laser. We evaluated the picosecond-laser-induced structural and morphological changes in DLC using micro-Raman spectroscopy via line measurements. We obtained the spatial distribution of the structure and morphology of DLC on Si by regression analysis of the Raman spectra. The photo-induced crater could be categorized into four regions: peripheral, morphological-change, structural-changes, and ablated regions. The structure and morphology of the peripheral region were similar to those of the as-received DLC. In the morphological-change region, which is inside the periphery region, the thickness of the DLC decreased without any structural changes. At the center of the crater, which is shown in black in the optical image, two regions were identified by Raman spectroscopy. On the outer side, there is a structural-change region where the graphitization of DLC materialized with a reduction in the film thickness. Inside the structural-change region, there is an ablated region where the DLC was degraded by laser ablation
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