A5053437523- Heat Transfer and Boiling Studies
- Heat Transfer and Optimization
- Fluid Dynamics and Thin Films
- Heat Transfer Mechanisms
- Fuel Cells and Related Materials
- Electrocatalysts for Energy Conversion
- Semiconductor materials and devices
- Fusion materials and technologies
- Advanced Sensor and Energy Harvesting Materials
- Fluid Dynamics and Turbulent Flows
- Turbomachinery Performance and Optimization
- Nanowire Synthesis and Applications
- Advanced battery technologies research
- Magnetic confinement fusion research
- Advanced Control Systems Optimization
- Copper Interconnects and Reliability
- Algebraic and Geometric Analysis
- Education and Learning Interventions
- Educational Systems and Policies
- Anodic Oxide Films and Nanostructures
- advanced mathematical theories
- Surface Modification and Superhydrophobicity
- Combustion and flame dynamics
- Nuclear reactor physics and engineering
- Tribology and Lubrication Engineering
Yonsei University
2010-2024
Seoul National University of Science and Technology
2006-2024
Severance Hospital
2024
Sangmyung University
2021-2023
Seoul National University
2000-2023
Soongsil University
2023
Korea Institute of Fusion Energy
2017-2021
Hanyang University
2008-2020
Institute for Basic Science
2020
Jeonbuk National University
2019
Morphologically driven dynamic wickability is essential for determining the hydrodynamic status of solid-liquid interface. We demonstrate that wicking can play an integral role in supplying and propagating liquid through interface, govern critical heat flux (CHF) against surface dry-out during boiling transfer. For quantitative control wicking, we manipulate characteristic lengths hexagonally arranged nanopillars within sub-micron range nanosphere lithography combined with top-down...
Enhancing the critical heat flux (CHF), which is capacity of dissipation, important to secure high stability in two-phase cooling systems. Coolant supply a dry hot spot major mechanism prevent surface burn-out for enhancing CHF. Here, we demonstrate more ready coolant using aligned silicon nanowires (A-SiNWs), with aspect ratio (>10) compared that conventional random (R-SiNWs), have disordered arrangement, additional CHF improvement. We propose volumetric wicking rate, represents properties...
Surface roughness is promotive of increasing their hydrophilicity or hydrophobicity to the extreme according intrinsic wettability determined by surface free energy characteristics a base substrate. Top-down etched silicon nanowires are used create superhydrophilic surfaces based on hemiwicking phenomenon. Using fluorine carbon coatings, converted from superhydrophobic maintain Cassie–Baxter state stability reducing quarter compared with silicon. We present robust criteria controlling height...
We fabricated Pd-coated rough Si nanowires, using a combination of electroless etching and Pd sputtering. The semi-densely distributed, vertical-standing which were clustered locally with inter-cluster distances several nm to μm, selected as basal platform. was coated only on the upper part nanowires in semi-dense configuration, their surface profile replicated morphology nanowires. showed good reversibility excellent hydrogen-sensing performance terms sensitivity (>300%), response time (<3...
We introduce a micro-electromechanical system (MEMS) energy harvester, designed for capturing flow energy. Moving beyond traditional vibration-based harvesting, our approach incorporates cylindrical oscillator mounted on MEMS chip, effectively harnessing wind through flow-induced vibration (FIV). A highlight of research is the development comprehensive fabrication process, utilizing 5.00 µm thick cantilever beam and piezoelectric film, optimized advanced micromachining techniques. This...
Crosslinked styrene–acrylate copolymers were synthesized and evaluated by swelling properties for oil-absorbency application. The effect of various polymerization conditions (crosslinking agent concentration, initiator monomer temperature) studied through oil-absorption tests using kerosene oil. oil absorbency was influenced mainly the degree crosslinking hydrophobicity copolymer units. moisture types acrylate also investigated. with a longer alkyl had higher in order stearyl (SA) > lauryl...
Abstract Nanoscale surface manipulation technique to control the roughness and wettability is a challenging field for performance enhancement in boiling heat transfer. In this study, micro-nano hybrid structures (MNHS) with hierarchical geometries that lead maximizing of area, roughness, are developed applications. MNHS consist micropillars or microcavities along nanowires having length diameter ratio about 100:1. fabricated by two-step silicon etching process, which dry micropattern...
We report combined electrochemical double-layer capacitance (EDLC) and pseudocapacitance in reduced graphene oxide (rGO) thick film like paper due to annealing temperature variations. The influence of (from room (RT) 1000 °C) on the structural, morphological, electrical, properties rGO was evaluated. Upon increasing temperature, shifting dominant (002) X-ray diffraction (XRD) peak a higher degree, volume expansion, red-shifting G band Raman spectra were observed. High-resolution transmission...
The incomplete growth of nanowires that are synthesized by template-assisted electrodeposition presents a major challenge for nanowire-based devices targeting energy and electronic applications. In electrodeposition, the in pores template is complex unstable. Here we show theoretically experimentally dynamics this process diffusion-limited, which results morphological instability driven race among nanowires. Moreover, use our findings to devise method control instability. By introducing...
We present a new concept of structured surface for enhanced boiling heat transfer that is capable self-adapting to the local thermal conditions. An array freestanding nanoscale bimorphs, structure consists two adjoining materials with large expansion mismatch, able deform under temperature change. Such gradually deforms as nucleate progresses due increase in wall superheat. The deformation caused by heated shown be favorable transfer, leading about 10% critical flux compared regular nanowire...
Micro-nano hybrid structure (MNHS) that comprises of microcavities and nanowires is a specific class MNHS considered to be ideal for two-phase boiling heat transfer applications. Realizing with electrodeposition favorable in transfer, but the realization has been very difficult time-consuming achieve. Here, we demonstrate simple, robust, rapid, photolithography-free route fabricate consists individual copper on large area. We show this can extremely beneficial compared state-of-the-art...