Publications by authors named "Byung-Hyun Kim"

Electrochemical alkaline water electrolysis offers significant economic advantages; however, these benefits are hindered by the high kinetic energy barrier of the water dissociation step and the sluggish kinetics of the hydrogen evolution reaction (HER) in alkaline media. Herein, the ensemble effect of binary types of Rh single atoms (Rh-N and Rh-O) on TiO-embedded carbon nanofiber (Rh-TiO/CNF) is reported, which serves as potent active sites for high-performance HER in anion exchange membrane water electrolyzer (AEMWE). Density functional theory (DFT) analyses support the experimental observations, highlighting the critical role of binary types of Rh single atoms facilitated by the TiO sites.

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Article Synopsis
  • Adsorption-based atmospheric water harvesting (AWH) offers a potential solution for water scarcity in dry regions, but challenges remain in developing efficient adsorbents for low humidity conditions.
  • The study presents a new metal-organic framework (MOF) called FO@HK, which incorporates fluorophenyl oligomers to enhance water capture and allow easy release through sunlight.
  • FO@HK outperforms existing sorbents, achieving significant water harvest rates in outdoor tests, illustrating a promising approach to improve water collection technologies.
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The ligand engineering for single-atom catalysts (SACs) is considered a cutting-edge strategy to tailor their electrocatalytic activity. However, the fundamental reasons underlying the reaction mechanism and the contemplation for which the actual active site for the catalytic reaction depends on the pyrrolic and pyridinic N ligand structure remain to be fully understood. Herein, we first reveal the relationship between the oxygen reduction reaction (ORR) activity and the N ligand structure for the manganese (Mn) single atomic site by the precisely regulated pyrrolic and pyridinic N coordination environment.

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Carbon monoxide (CO) is a key reactant in several Fischer-Tropsch processes, including those used in light olefin and methanol syntheses. However, it is highly toxic and causes serious poisoning of noble metal catalysts. Thus, a solid adsorbent that can selectively capture CO, especially at low concentrations, is required.

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The surging demand for environmental-friendly and safe electrochemical energy storage systems has driven the development of aqueous zinc (Zn)-ion batteries (ZIBs). However, metallic Zn anodes suffer from severe dendrite growth and large volume change, resulting in a limited lifetime for aqueous ZIB applications. Here, it is shown that 3D mesoporous carbon (MC) with controlled carbon and defect configurations can function as a highly reversible and dendrite-free Zn host, enabling the stable operation of aqueous ZIBs.

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Oxygen evolution reaction (OER) under acidic conditions becomes of significant importance for the practical use of a proton exchange membrane (PEM) water electrolyzer. In particular, maximizing the mass activity of iridium (Ir) is one of the maiden issues. Herein, the authors discover that the Ir-doped calcium copper titanate (CaCu₃Ti₄O₁₂, CCTO) perovskite exhibits ultrahigh mass activity up to 1000 A g for the acidic OER, which is 66 times higher than that of the benchmark catalyst, IrO .

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Background: Lagerstroemia indica (L. indica) is reported to have diverse biological activities including anti-inflammatory, anti-cancer, neuro-regulatory, antidiabetic, and antioxidant activity.

Aims: The purpose of this study is to examine the potential of hair growth promotion and/or hair loss prevention by L.

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Sodium-metal batteries (SMBs) are considered as a compliment to lithium-metal batteries for next-generation high-energy batteries because of their low cost and the abundance of sodium (Na). Herein, a 3D nanostructured porous carbon particle containing carbon-shell-coated Fe nanoparticles (PC-CFe) is employed as a highly reversible Na-metal host. PC-CFe has a unique 3D hierarchy based on sub-micrometer-sized carbon particles, ordered open channels, and evenly distributed carbon-coated Fe nanoparticles (CFe) on the surface.

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Article Synopsis
  • Machine-learning (ML) techniques are becoming popular for predicting material properties and enabling high-throughput screening, particularly using ML force fields (FFs) that match quantum mechanical accuracy.
  • The development of ML-FFs for polymers, like polytetrafluoroethylene (PTFE), is challenging due to the complex arrangement of atoms, but this study presents an effective approach using kernel functions and Gaussian processes.
  • The results show that even with training data from short PTFE chains, the ML-FF accurately predicts properties of longer chains and effectively describes various physical characteristics of PTFE when combined with molecular dynamics simulations.
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Upon microbial infection, host immune cells recognize bacterial cell envelope components through cognate receptors. Although bacterial cell envelope components function as innate immune molecules, the role of the physical state of the bacterial cell envelope (i.e.

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The interface formation and its effect on redox processes in agglomerated ceria nanoparticles (NPs) have been investigated using a multiscale simulation approach with standard density functional theory (DFT), the self-consistent-charge density functional tight binding (SCC-DFTB) method, and a DFT-parameterized reactive force-field (ReaxFF). In particular, we have modeled CeO NP pairs, using SCC-DFTB and DFT, and longer chains and networks formed by CeO or CeO NPs, using ReaxFF molecular dynamics simulations. We find that the most stable {111}/{111} interface structure is coherent whereas the stable {100}/{100} structures can be either coherent or incoherent.

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Next-generation lithium-ion batteries (LIBs) that satisfy the requirements for an electric vehicle energy source should demonstrate high reliability and safety for long-term high-energy-density operation. This inevitably calls for a novel approach to advance major components such as the separator. Herein, a separator is designed and fabricated via application of multilayer functional coating on both sides of a polyethylene separator.

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Background: Traditional medicine herbal prescriptions used for the treatment of skin disease have been developed into cosmetics. Sang-Hyul-Yun-Boo-Em (SHYBE) is a mixed herbal formula prescribed for patients with yin or blood deficiency patterns of skin disease. A previous study reported that SHYBE exercises anti-allergic and anti-inflammatory effects.

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A real-time humidity sensor based on a microwave resonator coupled with a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) conducting polymer (CP) film is proposed in this paper. The resonator is patterned on a printed circuit board and is excited by electromagnetic field coupling. To enhance the sensitivity of the sensor, the CP film is located in the area with the strongest electric field in the resonator.

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The biochemical characterization of virulence factors from entomopathogenic bacteria is important to understand entomopathogen-insect molecular interactions. Pseudomonas entomophila is a typical entomopathogenic bacterium that harbors virulence factors against several insects. However, the molecular actions of these factors against host innate immune responses are not clearly elucidated.

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Five genes encoding PhaP family proteins and one gene have been identified in the genome of symbiont strain RPE75. PhaP proteins function as the surface proteins of polyhydroxyalkanoate (PHA) granules, and the PhaR protein acts as a negative regulator of PhaP biosynthesis. Recently, we characterized one gene to understand the molecular cross talk between insects and gut symbionts.

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Chemical interactions between Pt and both pristine and defective carbon nanotubes (CNTs) that were functionalized with various surface functional groups, including atomic oxygen (-O), atomic nitrogen (-N), hydroxyl (-OH) and amine (-NH2) groups, were investigated through first-principles calculations. Our calculations suggest that the oxygen or nitrogen of the surface functional group can promote better structural stability of a Pt/CNT complex in terms of the binding energy enhancement between Pt and CNTs. Enhanced binding of the Pt/CNT complex would improve the long-term durability of the complex and thus enhance the catalytic activity of Pt catalysts supported on CNTs.

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Novel nonintrusive technologies for wrist pulse detection have been developed and proposed as systems for sleep monitoring using three types of radio frequency (RF) sensors. The three types of RF sensors for heart rate measurement on wrist are a flexible RF single resonator, array resonators, and an injection-locked PLL resonator sensor. To verify the performance of the new RF systems, we compared heart rates between presleep time and postsleep onset time.

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This paper presents the development of a non-contact, nonintrusive wrist pulse sensor based on the near-field variation of an array resonator. A compact resonator and its array were designed and fabricated on flexible substrate. The reflection coefficient of the resonator can vary as a function of the distance between the resonator and the walls of the major arteries, and the corresponding variation is utilized to obtain heart rate information at the wrist.

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This paper proposes a novel RF biosensor that utilizes a frequency synthesizer associated with a microstrip open-loop resonator for label-free biomolecular detection. The RF biosensor consists mainly of a resonance-assisted transducer and a phase locked loop (PLL) circuit. In this work, the performance of the RF biosensor is validated using the well-known biotin-streptavidin binding system.

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In this paper, a noncontact proximity vital sign sensor, using a phase locked loop (PLL) incorporated with voltage controlled oscillator (VCO) built-in planar type circular resonator, is proposed to enhance sensitivity in severe environments. The planar type circular resonator acts as a series feedback element of the VCO as well as a near-field receiving antenna. The frequency deviation of the VCO related to the body proximity effect ranges from 0.

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We have studied the very early stage of the room temperature oxidation of the externally-strained Si(001) surface using molecular dynamics simulation. It was found that the different treatment history of the sample under the same strain resulted in the difference in the number density of dimer. The as-prepared samples of different treatment history with 12.

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