Ewha Womans University · Materials Science
Professor Sang Wook Lee's research lab specializes in nanomaterials and nanomechanical systems, with a focus on developing advanced 2D materials and carbon-based nanodevices for sensing and energy applications. Key research directions include graphene-based nanomechanical resonators for ultra-sensitive mass detection, strain-engineered carbon nanotubes for Raman-based sensing, and novel memory devices using electromechanical actuation. The lab also explores biomedical applications of nanomaterials, such as fluorescent probes for reactive oxygen species and machine learning-assisted diagnosis of skin cancer using dermoscopic imaging.
Figures are computed from collected data and may differ slightly.
Although further data analysis is necessary to improve their accuracy, convolutional neural networks would be helpful to detect acral melanoma from dermoscopy images of the hands and feet.
Several new generation memory devices have been developed to overcome the low performance of conventional silicon-based flash memory. In this study, we demonstrate a novel non-volatile memory design based on the electromechanical motion of a cantilever to provide fast charging and discharging of a floating-gate electrode. The operation is demonstrated by using an electromechanical metal cantilever to charge a floating gate that controls the charge transport through a carbon nanotube field-effect
We present a technique for in situ Raman measurements of suspended individual single-walled carbon nanotubes (SWNTs) under strain. We observe a strong change in the radial breathing mode intensity with increasing strain as the nanotube moves out of (or into) resonance, and for strain greater than approximately 2%, there is a clear irreversible upshift in the G-mode frequencies accompanied by an increase in intensity of a broad peak at a position associated with the D mode. For lower strain, the
In this study, a shape design optimization method is proposed to improve the efficiency of a 3 kW permanent magnet synchronous motor (PMSM) used in an electric compressor intended for use in an electric vehicle. The proposed method improves the efficiency performance of the electric compressor by improving the torque characteristics of the initial PMSM model. The dimensions of the rotor were set as the design variables and were chosen to maximize efficiency and reduce cogging torque. During the
The efficacy of seven-day clarithromycin-based standard triple therapy (STT) for Helicobacter pylori has decreased in Korea over the past decade. The aim of this meta-analysis was to clarify the efficacy of first-line and second-line therapies in Korea. This systematic review will provide an overview of H. pylori eradication and present new therapeutic strategies used in Korea. An extensive search of the literature concerning STT, sequential therapy (SET), concomitant therapy (CT), bismuth-conta
The inherent properties of 2D materials-light mass, high out-of-plane flexibility, and large surface area-promise great potential for precise and accurate nanomechanical mass sensing, but their application is often hampered by surface contamination. Here we demonstrate a tri-layer graphene nanomechanical resonant mass sensor with sub-attogram resolution at room temperature, fabricated by a bottom-up process. We found that Joule-heating is effective in cleaning the graphene membrane surface, whic
Light shifting: Ratiometric fluorescent probes for hydrogen peroxide (H2O2) were developed through a focused library strategy. One of the probes in the library, showed a redshift of over 100 nm and an increase of over 30-fold in the emission intensity ratio (see scheme). This probe was utilized to detect H2O2 generated during glucose oxidation. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may b
Doppelte Lieferung: Multifunktionelle, selbstorganisierte, polymere Nanopartikel wurden synthetisiert, die den gleichzeitigen Transport von niedermolekularen Wirkstoffen und siRNA ermöglichen. Die Nanopartikel bestehen aus biologisch abbaubarer Hyaluronsäure zur Tumorerkennung und zum zellulären Transport sowie einem Analogon von ZnII-Dipicolylamin, das als künstlicher Phosphatbindungsrezeptor eine hohe Bindungsaffinität für siRNA bewirkt (siehe Schema). Detailed facts of importance to specialis
This thesis addresses problems and presents models for the detection and separation of specularities from Lambertian reflections using color and multiple images with different viewing directions. From the models, three algorithms are proposed and experimental results are presented. The first algorithm uses only color information for the separation of diffuse as well as sharp specularities and inter-reflections from Lambertian reflections through image segmentation. A computational model based on
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