Publications by authors named "Seong-hun Park"

Monodisperse nanoparticles of biodegradable polyhydroxyalkanoates (PHAs) polymers, copolymers of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB), are synthesized using a membrane-assisted emulsion encapsulation and evaporation process for biomedical resorbable adhesives. The precise control over the diameter of these PHA particles, ranging from 100 nm to 8 μm, is achieved by adjusting the diameter of emulsion or the PHA concentration. Mechanical properties of the particles can be tailored based on the 3HB to 4HB ratio and molecular weight, primarily influenced by the level of crystallinity.

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In this study, we investigated the optical properties of a transition metal dichalcogenide (TMD) substrate via Mie-scattering-induced surface analysis (MISA). Employing near-field optical microscopy and finite-difference time-domain (FDTD) simulations, we systemically prove and directly visualize the Mie scattering of superspherical gold nanoparticles (s-AuNPs) at the nanoscale. Molybdenum disulfide substrates exhibited optical isotropy, while rhenium disulfide (ReS) substrates showed anisotropic behavior attributed to the interaction with incident light's electric field.

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Background: A vaccine against COVID-19 has been developed; however, COVID-19 transmission continues. Although there have been many studies of comorbidities that have important roles in COVID-19, some studies have reported contradictory results.

Objective: This study was conducted using real-world data from COVID-19 patients in South Korea and aimed to investigate the impact of patient demographics and comorbidities on the infection rate and severity of COVID-19.

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Nanophotonics relies on precise control of refractive index (RI) which can be designed with metamaterials. Plasmonic superstructures of nanoparticles (NPs) can suggest a versatile way of tuning RI. However, the plasmonic effects in the superstructures demand 1 nm-level exquisite control over the interparticle gap, which is challenging in a sub-wavelength NPs.

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We present a confined condensation technique for the fabrication of layered copper hydroxide frameworks from lamellar copper-organic assemblies with long alkyl chains through the selective introduction of hydroxo bridging ligands. The complete transformations of two different lamellar copper-organic assemblies, Cu(CHSO)·4HO (Cu-DS) and Cu(CHCO)·2HO (Cu-lau), into the corresponding layered copper hydroxide frameworks, Cu(OH)(CHSO) (Cu-OH-DS) and Cu(OH)(CHCO) (Cu-OH-lau), were achieved via confined condensation. The magnetic properties of both lamellar copper-organic assemblies, Cu-DS and Cu-lau, and both layered copper hydroxide frameworks, Cu-OH-DS and Cu-OH-lau, were investigated.

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Purpose: The objective of this study was to investigate the effects of different microthread designs and implant-abutment connection configurations of scalloped implants on stress distribution in bone using three-dimensional finite element analysis.

Materials And Methods: Three different designs of scalloped implants (two different microthread designs and one without microthreads) with two different connection systems and two flat-top implants with similar connection systems were compared in a bone model that mimicked the anterior maxilla. Vertical and oblique (30-degree) loading with 100 N of force was applied to eight models.

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This work presents the synthesis, structure determination and magnetic properties of a new complex, phenethylammonium tetrachloromanganate(II), (C(6)H(5)CH(2)CH(2)NH(3))(2)MnCl(4) (Mn-PEA). Single crystals of Mn-PEA were obtained from methanol solution using the solvent-evaporation method at room temperature. The crystal structure of Mn-PEA was determined by single-crystal X-ray diffraction (orthorhombic, space group Pbca, a = 7.

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One-dimensional Cu(OH)(2) or CuO nanostructures were fabricated using inorganic-organic chain assemblies, Cu(C(n)H(2n+1)X)(2)·nH(2)O (X = CO(2), SO(4)) as a lamellar nanoreactor, along with NaOH treatment. The shapes and aspect ratios of the Cu(OH)(2) or CuO nanostructures could be varied by adjusting the hydrophobicity of the lamellar nanoreactors.

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Crystals of the title compound, (C(6)H(5)CH(2)CH(2)NH(3))(2)[CoCl(4)], were grown by the solvent-evaporation method. This inorganic-organic hybrid compound exhibits a layered structure in which isolated CoCl(4) inorganic layers alternate with bilayers of phenylethylammonium cations. Although the inorganic anion is zero-dimensional, the layered structure is stabilized via N-H⋯Cl hydrogen bonds.

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A series of hybrid inorganic-organic copper(II) hydroxy n-alkylsulfonate with a triangular lattice, Cu(2)(OH)(3)(C(n)H(2)(n)(+1)SO(3)) (n = 6, 8, 10), are prepared by anion exchange, starting from copper hydroxy nitrate Cu(2)(OH)(3)NO(3). These compounds show a layered structure as determined by X-ray diffraction, with interlayer distances of 14.3-34.

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We were able to synthesize unidirectionally aligned copper hydroxide nanorods from two-dimensional copper hydroxide nitrate by anion exchange reaction using NaOH without any membrane or template. The structural conversion from Cu2(OH)3NO3 to Cu(OH)2 was confirmed by XRD and FT-IR data. The synthesized copper hydroxide nanorods showed unidirectionally aligned and tightly bound arrays on a hexagonal plate, leading to giant nanorod bundles.

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Reaction of copper(II) salts with n-alkylsulfonate anions yields light blue lamellar Cu(C(n)H(2n + 1)SO3)2 x zH2O displaying distinct (mono/bi-layer) chain packing with increasing alkyl chain lengths. This may be attributed to the amphiphilic nature of the surfactants, i.e.

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