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Mun-Heon Hong

Bio: Mun-Heon Hong is an academic researcher from Seoul National University. The author has contributed to research in topics: Force spectroscopy & Quantum dot. The author has an hindex of 6, co-authored 8 publications receiving 145 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a scanning nanolithography is demonstrated by employing near-field optical microscopy with a pulled micropipette which is used for material transport as well as distance regulation.
Abstract: A scanning nanolithography is demonstrated by employing near-field optical microscopy with a pulled micropipette which is used for material transport as well as distance regulation. Delivering the photoresist through the small aperture (300 nm diameter) of the pulled pipette with the shear-force distance control, we have fabricated nanometric dots (300 nm diameter) on the gold-sputtered substrate. This scheme may be also useful in nanometric control of chemical reaction and repair of nanometric structures.

73 citations

Journal ArticleDOI
TL;DR: In this article, the axicon microlenses with different apex angles (118°, 107° and 90°) were fabricated on a singlemode bare optical fiber by using selective chemical etching technique.

24 citations

Journal ArticleDOI
TL;DR: This work has demonstrated high-resolution shear-mode magnetic force microscopy (MFM) using a quartz tuning fork in ambient conditions and obtained MFM images with a spatial resolution less than 100 nm and a frequency resolution of ∼1 mHz, values which are achieved by phase shift detection methods.
Abstract: We have demonstrated high-resolution shear-mode magnetic force microscopy (MFM) using a quartz tuning fork in ambient conditions. A commercial magnetic cantilever tip was attached to one prong of the tuning fork to realize shear-mode MFM operation. We have obtained MFM images with a spatial resolution of less than 100 nm and demonstrated a frequency resolution of ∼1 mHz, values which are achieved by phase shift detection methods.

19 citations

Journal ArticleDOI
TL;DR: A nanopipette combined with a quartz tuning fork-atomic force microscope system (nanopipette/QTF-AFM) is introduced, and experimental and theoretical investigations of the nanoscale materials used are described.
Abstract: This paper introduces a nanopipette combined with a quartz tuning fork-atomic force microscope system (nanopipette/QTF-AFM), and describes experimental and theoretical investigations of the nanoscale materials used. The system offers several advantages over conventional cantilever-based AFM and QTF-AFM systems, including simple control of the quality factor based on the contact position of the QTF, easy variation of the effective tip diameter, electrical detection, on-demand delivery and patterning of various solutions, and in situ surface characterization after patterning. This tool enables nanoscale liquid delivery and nanofabrication processes without damaging the apex of the tip in various environments, and also offers force spectroscopy and microscopy capabilities.

14 citations

Journal ArticleDOI
TL;DR: The proposed and demonstrated novel FM-AFM technique provides high experimental sensitivity in the measurement of the viscoelastic forces associated with the confined nano-water meniscus, short response time, and insensitivity to amplitude noise, which are essential for precision dynamic force spectroscopy and microscopy.
Abstract: We present a platform for the quartz tuning fork (QTF)-based, frequency modulation atomic force microscopy (FM-AFM) system for quantitative study of the mechanical or topographical properties of nanoscale materials, such as the nano-sized water bridge formed between the quartz tip (~100 nm curvature) and the mica substrate. A thermally stable, all digital phase-locked loop is used to detect the small frequency shift of the QTF signal resulting from the nanomaterial-mediated interactions. The proposed and demonstrated novel FM-AFM technique provides high experimental sensitivity in the measurement of the viscoelastic forces associated with the confined nano-water meniscus, short response time, and insensitivity to amplitude noise, which are essential for precision dynamic force spectroscopy and microscopy.

12 citations


Cited by
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Book ChapterDOI
01 Jan 2013
TL;DR: This chapter highlights a variety of techniques that are commonly used to measure contact angles, including the conventional telescope-goniometer method, the Wilhelmy balance method, and the more recently developed drop-shape analysis methods.
Abstract: This chapter highlights a variety of techniques that are commonly used to measure contact angles, including the conventional telescope-goniometer method, the Wilhelmy balance method, and the more recently developed drop-shape analysis methods. The various applications and limitations of these techniques are described. Notably, studies of ultrasmall droplets on solid surfaces allow wetting theories to be tested down to the nanometer scale, bringing new insight to contact angle phenomena and wetting behavior.

1,259 citations

Journal ArticleDOI
TL;DR: This work describes the physical properties of carbon nanotubes as well as the theoretical models used to derive these properties, and shows how these properties can be modified to improve the quality of the research.
Abstract: 7.1. Water Structure in Carbon Nanotubes 5020 7.2. Radial, Axial, and Total Water Density 5023 7.3. Hydrogen Bonds 5024 7.4. Filling Carbon Nanotubes with Water 5025 7.5. Dipole Moment 5026 7.6. Proton Transport in Water 5027 7.7. Transport Properties 5027 8. Driven Flow 5029 9. Charged Carbon Nanotubes 5029 10. Polarizable Carbon Nanotubes 5030 11. Selective Partitioning 5030 12. Functionalized Carbon Nanotubes 5031 13. Conclusions 5031 14. Acknowledgments 5031 15. References 5031

448 citations

Journal ArticleDOI
TL;DR: The universality and versatility of the fluidFM will stimulate original experiments at the submicrometer scale not only in biology but also in physics, chemistry, and material science.
Abstract: We describe the fluidFM, an atomic force microscope (AFM) based on hollow cantilevers for local liquid dispensing and stimulation of single living cells under physiological conditions. A nanofluidic channel in the cantilever allows soluble molecules to be dispensed through a submicrometer aperture in the AFM tip. The sensitive AFM force feedback allows controlled approach of the tip to a sample for extremely local modification of surfaces in liquid environments. It also allows reliable discrimination between gentle contact with a cell membrane or its perforation. Using these two procedures, dyes have been introduced into individual living cells and even selected subcellular structures of these cells. The universality and versatility of the fluidFM will stimulate original experiments at the submicrometer scale not only in biology but also in physics, chemistry, and material science.

341 citations

Journal ArticleDOI
TL;DR: The transport behavior of water molecules inside a model carbon nanotubes is investigated by using nonequilibrium molecular dynamcis (NMED) simulations and the shearing stress between the nanotube wall and the water molecules is identified as a key factor in determining the nanofluidic properties.
Abstract: The transport behavior of water molecules inside a model carbon nanotube is investigated by using nonequilibrium molecular dynamcis (NMED) simulations. The shearing stress between the nanotube wall and the water molecules is identified as a key factor in determining the nanofluidic properties. Due to the effect of nanoscale confinement, the effective shearing stress is not only size sensitive but also strongly dependent on the fluid flow rate. Consequently, the nominal viscosity of the confined water decreases rapidly as the tube radius is reduced or when a faster flow rate is maintained. An infiltration experiment on a nanoporous carbon is performed to qualitatively validate these findings.

227 citations