Publications by authors named "Junho Oh"

Laser-welding is a promising technique for welding NiTi shape memory alloys with acceptable tensile strength and comparable corrosion performance for biomedical applications. The microstructural characteristics and localized corrosion behavior of NiTi alloys in a simulated body fluid (SBF) environment are evaluated. A microstructural examination indicated the presence of fine and equiaxed grains with a B2 austenite phase in the base metal (BM), while the weld metal (WM) had a coarse dendritic microstructure with intermetallic precipitates including TiNi and NiTi.

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A consensus was built in the first half of the 20th century, which was further debated more than 3 decades ago, that the wettability and condensation mechanisms on smooth solid surfaces are modified by the adsorption of organic contaminants present in the environment. Recently, disagreement has formed about this topic once again, as many researchers have overlooked contamination due to its difficulty to eliminate. For example, the intrinsic wettability of rare earth oxides has been reported to be hydrophobic and non-wetting to water.

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Article Synopsis
  • Physical unclonable functions (PUFs) are being developed as a superior alternative for information security, as they generate unique cryptographic keys that cannot be replicated, although traditional PUFs face limitations like fixed keys and slower authentication with larger datasets.
  • The new supersaturated solution-based PUF (S-PUF) improves the authentication process by using sodium acetate crystallization, allowing for quicker, hierarchical authentication and the ability to rewrite cryptographic keys on demand.
  • By manipulating the temperature to control crystal characteristics and including global parameters like angle of rotation, the S-PUF enhances the cryptographic key generation process, paving the way for a more flexible and efficient anti-counterfeiting solution.
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This study aimed to evaluate the correlation between plasma lipocalin-2 (LCN2) levels and myelin oligodendrocyte glycoprotein (MOG)-immunoglobulin G (IgG) seropositivity in patients with optic neuritis. Peripheral blood samples were collected from 19 patients with optic neuritis and 20 healthy controls. Plasma LCN2 and MOG-IgG levels were measured using enzyme-linked immunosorbent assay and a cell-based assay, respectively.

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The surface free energy of rare earth oxides (REOs) has been debated during the last decade, with some reporting REOs to be intrinsically hydrophilic and others reporting hydrophobic. Here, we investigate the wettability and surface chemistry of pristine and smooth REO surfaces, conclusively showing that hydrophobicity stems from wettability transition due to volatile organic compound adsorption. We show that, for indoor ambient atmospheres and well-controlled saturated hydrocarbon atmospheres, the apparent advancing and receding contact angles of water increase with exposure time.

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Slippery liquid infused porous surfaces (SLIPS) are an important class of repellent materials, comprising micro/nanotextures infused with a lubricating liquid. Unlike superhydrophobic surfaces, SLIPS do not rely on a stable air-liquid interface and thus can better manage low surface tension fluids, are less susceptible to damage under physical stress, and are able to self-heal. However, these collective properties are only efficient as long as the lubricant remains infused, which has proved challenging.

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Many medical books of the late Joseon Dynasty were based on the medical knowledge of Donguibogam. For this reason, most of the studies have explained the medicine of the late Joseon Dynasty focusing on Donguibogam. However, the appearance of medicine in the late Joseon Dynasty is more complex than that.

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Lubricant-infused surfaces (LISs) and slippery liquid-infused porous surfaces (SLIPSs) have shown remarkable success in repelling low-surface-tension fluids. The atomically smooth, defect-free slippery surface leads to reduced droplet pinning and omniphobicity. However, the presence of a lubricant introduces liquid-liquid interactions with the working fluid.

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Periodic nanotube arrays render enhanced functional properties through their interaction with light and matter, but to reach optimal performance for technologically prominent applications, such as wettability or photonics, structural fine-tuning is essential. Nonetheless, a universal and scalable method providing independent dimension control, high aspect ratios, and the prospect of further structural complexity remains unachieved. Here, we answer this need through an atomic layer deposition (ALD)-enabled multiple patterning.

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Nanoimprinting lithography (NIL) is a next-generation nanofabrication method, capable of replicating nanostructures from original master surfaces. Here, we develop highly scalable, simple, and nondestructive NIL using a dissolvable template. Termed dissolvable template nanoimprinting lithography (DT-NIL), our method utilizes an economic thermoplastic resin to fabricate nanoimprinting templates, which can be easily dissolved in simple organic solvents.

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Research on a terrain-blind walking control that can walk stably on unknown and uneven terrain is an important research field for humanoid robots to achieve human-level walking abilities, and it is still a field that needs much improvement. This paper describes the design, implementation, and experimental results of a robust balance-control framework for the stable walking of a humanoid robot on unknown and uneven terrain. For robust balance-control against disturbances caused by uneven terrain, we propose a framework that combines a capture-point controller that modifies the control reference, and a balance controller that follows its control references in a cascading structure.

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Biofouling disrupts the surface functionality and integrity of engineered substrates. A variety of natural materials such as plant leaves and insect wings have evolved sophisticated physical mechanisms capable of preventing biofouling. Over the past decade, several reports have pinpointed nanoscale surface topography as an important regulator of surface adhesion and growth of bacteria.

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Superhydrophobicity has received significant attention over the past three decades owing to its significant potential in self-cleaning, anti-icing and drag reduction surfaces, energy-harvesting devices, antibacterial coatings, and enhanced heat transfer applications. Superhydrophobicity can be obtained via the roughening of an intrinsically hydrophobic surface, the creation of a re-entrant geometry, or by the roughening of a hydrophilic surface followed by a conformal coating of a hydrophobic material. Intrinsically hydrophobic surfaces have poor thermophysical properties, such as thermal conductivity, and thus are not suitable for heat transfer applications.

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In the 15th century, Joseon dynasty's goal for the stabilization of the ruling system, the ideological freedom of the era, and the necessity of medicine due to the introduction of Jin and Yuan dynasty's medicine led to the increased interest in medicine by the nobility along with tolerant practice. The practice of reading medical books is a good example of this institutional demonstration. However, by the end of the 15th century, a noticeable change had taken place.

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Robotic and athletic achievements shared the stage at the PyeongChang 2018 Winter Olympic Games.

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Geologic storage of carbon dioxide (CO) is considered a viable strategy for significantly reducing anthropogenic CO emissions into the atmosphere; however, understanding the flow mechanisms in various geological formations is essential for safe storage using this technique. This study presents, for the first time, a two-phase (CO and brine) flow visualization under reservoir conditions (10 MPa, 50 °C) for a highly heterogeneous conglomerate core obtained from a real CO storage site. Rock heterogeneity and the porosity variation characteristics were evaluated using X-ray computed tomography (CT).

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Laser-ablation electrospray ionization (LAESI) imaging mass spectrometry (IMS) is an emerging bioanalytical tool for direct imaging and analysis of biological tissues. Performing ionization in an ambient environment, this technique requires little sample preparation and no additional matrix, and can be performed on natural, uneven surfaces. When combined with optical microscopy, the investigation of biological samples by LAESI allows for spatially resolved compositional analysis.

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In this study, a data-driven method for predicting CO leaks and associated concentrations from geological CO sequestration is developed. Several candidate models are compared based on their reproducibility and predictive capability for CO concentration measurements from the Environment Impact Evaluation Test (EIT) site in Korea. Based on the data mining results, a one-dimensional solution of the advective-dispersive equation for steady flow (i.

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Droplet evaporation is an important phenomenon governing many man-made and natural processes. Characterizing the rate of evaporation with high accuracy has attracted the attention of numerous scientists over the past century. Traditionally, researchers have studied evaporation by observing the change in the droplet size in a given time interval.

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Evolutionary pressure has pushed many extant species to develop micro/nanostructures that can significantly affect wettability and enable functionalities such as droplet jumping, self-cleaning, antifogging, antimicrobial, and antireflectivity. In particular, significant effort is underway to understand the insect wing surface structure to establish rational design tools for the development of novel engineered materials. Most studies, however, have focused on superhydrophobic wings obtained from a single insect species, in particular, the Psaltoda claripennis cicada.

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The ethanolic extract of the needles of Pinus thunbergii was found to suppress antigen mediated degranulation of rat basophilic leukemia (RBL-2H3) cells. A new neolignan glycoside, named pinusthunbergiside A (1), as well as six known neolignan glycosides (2-7) were isolated from the ethanolic extract using bioassay-guided fractionation. Their structures were elucidated by a combination of 1D and 2D NMR, HRESI-MS, and circular dichroism (CD) data.

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A highly stretchable hybrid nanogenerator has been developed using a micro-patterned piezoelectric polymer P(VDF-TrFE), PDMS-CNT composite, and graphene nanosheets. Mechanical and thermal energies are simultaneously harvested from a single cell of the device. The hybrid nanogenerator exhibits high robustness behavior even after 30% stretching and generates very stable piezoelectric and pyroelectric power outputs due to micro-pattern designing.

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The recent advance in SNP genotyping has made a significant contribution to reduction of the costs for large-scale genotyping. The development also has dramatically increased the size of the SNP genotype data. The increase in the volume of the data, however, has posed a huge obstacle to the conventional analysis techniques that are typically vulnerable to the high-dimensionality problem.

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The issue of cold damage is one of the major topics of orthodox medicine in East Asia. From the historical view of point, most of the medical practitioners have turned The Theory of Cold Damage to account as their grounds for justifying their own argument. However, it is rare to find a book related to The Theory of Cold Damage in Korea's traditional medicine.

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Article Synopsis
  • Traditional Korean medicine (TKM) evolved from traditional Chinese medicine (TCM) as Korea sought to create its own medical system, particularly after the introduction of Chinese medical texts in the 10th century.
  • The publication of "Dongeuibogam" by Dr. Joon Hur in the 17th century marked a significant shift towards an independent Korean medical practice, focusing on the individual characteristics of patients rather than just their symptoms.
  • TKM is recognized as a whole-person-centered approach to medicine, distinct from TCM, with its principles further developed by Dr. Jae Ma Lee in the early 20th century.*
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