Sang Im Lee

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The nonlinear dynamic response of atomic force microscopy cantilevers tapping on a sample is discussed through theoretical, computational, and experimental analysis. Experimental measurements are presented for the frequency response of a specific microcantilever-sample system to demonstrate the nonlinear features, including multiple jump phenomena leading(More)
Dynamic force microscopy (DFM) utilizes the dynamic response of a resonating probe tip as it approaches and retracts from a sample to measure the topography and material properties of a nanostructure. We present recent results based on nonlinear dynamical systems theory, computational continuation techniques and detailed experiments that yield new(More)
– Magneto-optical imaging reveal that below 10 K the penetration of magnetic flux in MgB2 films is dominated by dendritic structures abruptly formed in response to an applied field. The dendrites show a temperature-dependent morphology ranging from quasi-1D at 4 K to large tree-like structures near 10 K. This behaviour is responsible for the anomalous noise(More)
This paper investigates speech rhythm in standard Seoul Korean using recently developed durational rhythmic measures. Traditionally, languages are classified into 'stress-timed' and 'syllable-timed' (Abercrombie, 1967), with English and German being typical stress-timed languages, French and Italian typical syllable-timed languages. Later works suggested a(More)
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