Sangmin Jeon

We developed a novel solar steam generator (SSG) with high solar conversion efficiency and excellent salt resistance. A CO₂ laser was used to convert the surface of basswood to graphitic carbon layers (GCL), and various grid patterns of GCL were created on wood. The low thermal conductivity of wood suppressed heat loss to bulk water, and the presence of the grooves in the grid increased the evaporation rate by increasing the surface area to absorb more sunlight. In addition, the suppl

A CO2 laser engraver was used to synthesize conductive graphitic carbon directly on cellulose nanofiber (CNF) substrates under ambient conditions. CNFs were prepared via a TEMPO (2,2,6,6-tetramethylpiperidin-1-oxyl radical)-mediated oxidation reaction of bleached pulp, and a porous paper or a transparent film was obtained based on the drying conditions employed. Laser irradiation on a porous CNF paper led to the formation of amorphous carbon owing to an increase in temperature. Subsequent lasing

A CO₂ laser was employed to create a rectangle (4 × 2 mm²) of a conductive graphitic carbon layer (GCL) directly on a cellulose substrate. By tilting the substrate while keeping the laser power constant, the laser power density was gradually changed while scanning in the direction of the long side of the rectangle, due to deviation of the laser focus. As the laser beam defocus distance increased, the laser intensity at the substrate decreased, and the oxygen-to-carbon ratio

We developed a nanofiber membrane that blocks particulate matters (PMs) and monitors respiration. The membrane was composed of polyacrylonitrile (PAN) nanofibers and was prepared by electrospinning. An electrically conductive metal organic framework (MOF) was synthesized directly on the nanofiber by a two-step hydrothermal reaction. Both membranes achieved similar filtering efficiency (>99%) for fine dust particles, but the hybrid membrane more efficiently filtered incense smoke containing oil d

The development of heat-generating magnetic nanostructures is critical for the effective management of tumors using magnetic hyperthermia. Herein, we demonstrate that polyethylene glycol (PEG)-coated iron oxide (magnetite, Fe₃O₄) multigranule nanoclusters (PEG-MGNCs) can enhance the efficiency of hyperthermia-based tumor suppression <i>in vitro</i> and <i>in vivo</i>. MGNCs consisting of granules (crystallites) measuring 22.9 nm in diameter were prepared <i>via</i> the hydr

A multiple-point deflection technique has been developed for the instant measurement of microcantilever curvature. Eight light-emitting diodes are focused on various positions of a gold-coated silicon cantilever through optical fibers, and temperature change or chemical adsorption induces cantilever bending. The deflection at each point on the cantilever is measured with subnanometer precision by a position-sensitive detector, and thus the curvature of the cantilever is obtained.

In this letter, a method to measure the torsional spring constant of a microcantilever is described. The cantilever was twisted laterally without any normal load by inducing the Lorentz force. An electrical current was applied to the cantilever in a magnetic field, and the torsional resonance frequency of the cantilever was obtained. Based on the observation that the torsional resonance frequency is the same as the second resonance peak of the thermally vibrating cantilever, the ratio of deflect

Modulus-tunable microcantilevers are fabricated from magnetorheological elastomers (MREs) consisting of polydimethylsiloxane and carbonyl iron particles by using a simple sandwich molding method. Depending on the presence or absence of an external magnetic field during curing, isotropic or anisotropic MRE cantilevers are obtained. Randomly distributed particles are present in the polymer matrix of the isotropic microcantilevers, whereas the particles in the anisotropic microcantilevers are align

We have developed a method for rapid detection of pathogenic bacteria from water using a virtual net comprising magnetic nanoparticle clusters (MNC). When an external magnetic field was applied to the antibody-functionalized MNC (Ab-MNC) solution in a glass tube (GT), the Ab-MNCs were aligned along the direction of the applied magnetic field to form a wall of MNCs. The injection of a liquid into the GT pushed the MNCs to flow when the drag force exceeded the magnetic force that held the MNCs. In

We have developed a virtual filter that quickly and efficiently captures and detects pathogenic bacteria in large amounts of water. The virtual filter comprised magnetic nanoparticle chains (MNCs) obtained by cross-linking alginate-coated magnetic nanoparticles (MNPs). When the MNC solution in a disposable plastic tube was exposed to an external magnetic field, the MNCs were aligned along the magnetic field lines, forming a filter similar to a whale's baleen filtering system. A Halbach ring that