Publications by authors named "Jung-Hoon Yang"

The two most critical technical issues in Zn-based batteries, dendrite formation, and hydrogen evolution reaction, can be simultaneously addressed by introducing negatively charged fibrous ZrO as a separator. Electron redistribution between ZrO and Zn ions renders the ZrO surface a preferred adsorption site for Zn ions, making surface conduction the primary ion-transport mode. Surface conduction enables fibrous ZrO to exhibit a 6.

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The chemical degradation of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-based aqueous energy storage and catalytic systems is pH sensitive. Herein, we voltammetrically monitor the local pH (pH) at a Pt ultramicroelectrode (UME) upon electro-oxidation of imidazolium-linker functionalized TEMPO and show that its decrease is associated with the greater acidity of the cationic (oxidized) rather than radical (reduced) form of TEMPO. The protons that drive the decrease in pH arise from hydrolysis of the conjugated imidazolium-linker functional group of 4-[2-(-methylimidazolium)acetoxy]-2,2,6,6-tetramethylpiperidine-1-oxyl chloride (MIMAcO-T), which was studied in comparison with 4-hydroxyl-TEMPO (4-OH-T).

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Based on the ambipolar characteristics and high solubility of ZnI, zinc-polyiodide flow batteries (ZIFB) have attracted attention as high-energy density flow batteries. However, due to the various oxidation products of iodide (I) and the formation of iodine (I) solid precipitates at the positive electrode, the limiting state-of-charge (SoC) of ZIFB has not been clearly defined. Herein, a clear definition of SoC in ZIFBs is given based on the thermodynamic relationship among I, I, I, and I in the electrolyte.

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The use of iodide as the positive redox-active species in redox flow batteries has been highly anticipated owing to its attractive features of high solubility, excellent reversibility, and low cost. However, the electro-oxidation reaction of iodide (I) is very complicated, giving various possible products such as iodine (I), polyiodides (I), and polyiodines (I) with ≥ 1. In particular, the electro-oxidation of I/I and I/I occurs in competition depending on the applied potential.

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A series of indolo[3,2-b]indole (IDID) derivatives are designed as a novel structural platform for thermally activated delayed fluorescence (TADF) emitters. Intramolecular charge transfer (ICT)-type molecules consisting of IDID donor (D) and various acceptor (A) moieties are synthesized and characterized in the protocol of the systematical structure-property correlation. IDID derivatives exhibit high efficiency, prompt fluorescence as well as TADF with emission ranges tuned by the chemical structure of the acceptor units.

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Capacity decay in vanadium redox flow batteries during charge-discharge cycling has become an important issue because it lowers the practical energy density of the battery. The battery capacity tends to drop rapidly within the first tens of cycles and then drops more gradually over subsequent cycles during long-term operation. This paper analyzes and discusses the reasons for this early capacity decay.

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Background: The appropriate indication for coronary computed tomographic angiography (CTA) as a part of preoperative evaluation has not been defined yet. We investigated the value of coronary CTA in patients undergoing noncardiac surgery.

Methods And Results: We included 844 patients (median age, 67 years; male sex, 62%) who underwent coronary CTA for screening of coronary artery disease before noncardiac surgery.

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Background: The clinical benefit of extracorporeal cardiopulmonary resuscitation (E-CPR) has been proved in short-term follow-up studies. However, the benefit of E-CPR beyond 1 year has been not known. We investigated 2-year outcome of patients who received E-CPR or conventional CPR (C-CPR).

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Cutaneous horn is the clinical description of a hyperproliferation of compact keratin in response to a wide array of underlying benign and malignant pathologic changes. We report here on a case of cutaneous horn that originated from keratoacanthoma in a 76-year-old woman. Grossly, a 2.

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In mammalian brain, D-serine is synthesized from L-serine by serine racemase, and it functions as an obligatory co-agonist at the glycine modulatory site of N-methyl-D-aspartate (NMDA)-selective glutamate receptors. Although diminution in D-serine level has been implicated in NMDA receptor hypofunction, which is thought to occur in schizophrenia, the source of the precursor L-serine and its role in D-serine metabolism in adult brain have yet to be determined. We investigated whether L-serine synthesized in brain via the phosphorylated pathway is essential for D-serine synthesis by generating mice with a conditional deletion of D-3-phosphoglycerate dehydrogenase (Phgdh; EC 1.

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The effects of surface charge density on DNA hybridization have been investigated on a mixture of hydrogen-, oxygen-, and amine-terminated diamond surfaces. A difference in the hybridization efficiencies of complementary and mismatched DNA was clearly observed by fluorescence and potentiometric observations at a particular coverage of oxygen. In the fluorescence observation, singly mismatched DNA was detected with high contrast after appropriate hybridization on the surface with 10-20% oxygen coverage.

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We have introduced pH sensors fabricated on diamond thin films through modification of the surface-terminated atom. We directly modified the diamond surface from hydrogen to amine or oxygen with ultraviolet (UV) irradiation under ammonia gas. The quantified amine site based on the spectra obtained by X-ray photoelectron spectroscopy (XPS) is 26% (2.

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Charge detection biosensors have recently become the focal point of biosensor research, especially field-effect-transistors (FETs) that combine compactness, low cost, high input, and low output impedances, to realize simple and stable in vivo diagnostic systems. However, critical evaluation of the possibility and limitations of charge detection of label-free DNA hybridization using silicon-based ion-sensitive FETs (ISFETs) has been introduced recently. The channel surface of these devices must be covered by relatively thick insulating layers ( SiO2, Si3N4, Al2O3, or Ta2O5) to protect against the invasion of ions from solution.

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Here, we report a novel method of micropatterning oligonucleotides via aromatic groups as linkers on partially amino-terminated diamond and the inherence on subsequent hybridization. The covalent immobilization of probe oligonucleotides and characterization of immobilized probe oligonucleotides with carboxylic compounds were investigated by X-ray photoelectron spectroscopy (XPS). To confirm the effects of linker flexibility in a low amino group on diamond for probe oligonucleotides, three kinds of dicarboxylic compound--adipic acid, terephthalic acid, and trimesic acid--were used for immobilization of probe oligonucleotides, like linkers; and these oligonucleotides were hybridized with target oligonucleotides labeled with Cy 5 on the micropatterned diamond surface.

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