Publications by authors named "Hyunchul Ahn"

Article Synopsis
  • This study presents a new smart hydrogel that responds to temperature changes and has improved electrical properties due to the integration of liquid metal particles (LMPs) during its creation.
  • The LMPs not only enhance the hydrogel’s volume switching ability but also provide a stable electrical switching ratio, achieving a significant electrical switch of 6.1 orders of magnitude.
  • The hydrogel is also noted for its strong mechanical properties, biocompatibility, and self-healing abilities, making it a potential candidate for use in long-term bioelectronic implants that need to work well with human tissue.
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Polyacrylonitrile (PAN) fiber is the most widely used carbon fiber precursor, and methyl acrylate (MA) copolymer is widely used for research and commercial purposes. The properties of P (AN-MA) fibers improve increasingly as the molecular weight increases, but high-molecular-weight materials have some limitations with respect to the manufacturing process. In this study, P (AN-MA) precursor fibers of different molecular weights were prepared and analyzed to identify an efficient carbon fiber precursor manufacturing process.

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Although polyacrylonitrile (PAN)-based carbon fibers have been successfully commercialized owing to their excellent material properties, their actual mechanical performance is still much lower than the theoretical values. Meanwhile, there is a growing demand for the use of superior carbon fibers. As such, many studies have been conducted to improve the mechanical performance of carbon fibers.

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Collagen is a protein that is a major component of animal skins and tendons. It is used in various medical, cosmetic, and food products through extraction and purification. The fibrous products of purified collagen fibers extracted from raw mammal materials have relatively excellent mechanical properties and are used for high-end medical products.

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Polyacrylonitrile (PAN) fibers are typically used as precursor fibers for carbon fiber production, produced through wet-spinning processes. The drawing process of the spun fiber can be classified into dry and wet drawing processes. It is known that the drawing stability and stretching ratio differ depending on the drawing process; however, the elementary characteristics are approximately similar.

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Regenerating articular cartilage in vivo from cultured chondrocytes requires that the cells be cultured and implanted within a biocompatible, biodegradable scaffold. Such scaffolds must be mechanically stable; otherwise chondrocytes would not be supported and patients would experience severe pain. Here we report a new 3D braid scaffold that matches the anisotropic (gradient) mechanical properties of natural articular cartilage and is permissive to cell cultivation.

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After a disability occurs, vocational rehabilitation is essential for promoting return to society and improving quality of life. To facilitate vocational rehabilitation, an effective counseling by human expert is essential. However, the number of the experts is not many.

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Panchromatic 1,6-bis(N-phenyl-p-(R)-phenylamino)pyrenes, 2R, were obtained from Buchwald-Hartwig coupling reactions between N-phenyl-p-(R)-phenylamines and 1,6-dibromopyrene. The photophysical properties of 2R corresponded well to the electron-withdrawing and -donating nature of the diarylamine substituents, exhibiting a full color visible range between 454 and 620 nm. In particular, a deep blue 2CN showed a high radiative rate constant of 2.

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