Publications by authors named "Young-Jae Song"

Article Synopsis
  • Lithium, known for its high capacity and low redox potential, faces practical issues in battery applications due to uneven deposition and dendrite formation, posing safety risks.
  • Our research indicates that incorporating silver-based materials improves the uniformity of lithium deposition on modified surfaces, addressing these safety challenges and enhancing cycling stability.
  • We employed advanced techniques like Kelvin probe force microscopy and electrochemical atomic force microscopy to investigate the electrical properties and mechanisms of lithium deposition, aiding in the design of safer, more efficient lithium metal batteries.
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Lithium metal is promising for high-capacity batteries because of its high theoretical specific capacity of 3860 mAh g and low redox potential of -3.04 V versus the standard hydrogen electrode. However, it encounters challenges, such as dendrite formation, which poses risks of short circuits and safety hazards.

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One of the exotic expectations in the 2D curved spacetime is the geometric potential from the curvature of the 2D space, still possessing unsolved fundamental questions through Dirac quantization. The atomically thin 2D materials are promising for the realization of the geometric potential, but the geometric potential in 2D materials is not identified experimentally. Here, the curvature-induced ring-patterned bound states are observed in structurally deformed 2D semiconductors and formulated the modified geometric potential for the curvature effect, which demonstrates the ring-shape bound states with angular momentum.

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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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Curvature is a general factor for various two-dimensional (2D) materials due to their flexibility, which is not yet fully unveiled to control their physical properties. In particular, the effect of structural disorder with random curvature formation on excitons in 2D semiconductors is not fully understood. Here, the correlation between structural disorder and exciton formation in monolayer MoS on SiO was investigated by using photoluminescence (PL) and Raman spectroscopy.

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Quantum dots possess exceptional optoelectronic properties, such as narrow bandwidth, controllable wavelength, and compatibility with solution-based processing. However, for efficient and stable operation in electroluminescence mode, several issues require resolution. Particularly, as device dimensions decrease, a higher electric field may be applied through next-generation quantum dot light-emitting diode (QLED) devices, which could further degrade the device.

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Objective: Intracochlear schwannoma is very rare, and complete loss of hearing is inevitable after the removal of this tumor. Here, we discuss cochlear implantation (CI) performed simultaneously with the removal of an intracochlear schwannoma.

Study Design: Retrospective single-center study.

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In this study, we present single-crystalline pyramid-shaped (SP) TiC particles synthesized on a stacked melt (copper)-solid (titanium) substrate using a biphase diffusion synthesis (BDS) method, in which different sizes ranging from nano- to micrometer scale were obtained within the copper melt with the {100} planes exposed to air. Direct observation and further plasma treatment of the pyramids at different self-assembly stages facilitated the investigation of their growth mode, especially in the horizontal plane. The dendritic growth mode along with the edge and corner-shared modes of the SP TiC particles frozen on the copper surface was investigated.

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Solution-based processing of two-dimensional (2D) nanomaterials is highly desirable, especially for the low-temperature large-area fabrication of flexible multifunctional devices. MXenes, an emerging family of 2D materials composed of transition metal carbides, carbonitrides, or nitrides, provide excellent electrical and electrochemical properties through aqueous processing. Here, we further expand the horizon of MXene processing by introducing a polymeric superdispersant for MXene nanosheets.

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Optoelectronic devices consist of heterointerfaces formed between dissimilar semiconducting materials. The relative energy-level alignment between contacting semiconductors determinately affects the heterointerface charge injection and extraction dynamics. For perovskite solar cells (PSCs), the heterointerface between the top perovskite surface and a charge-transporting material is often treated for defect passivation to improve the PSC stability and performance.

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The g-CN monolayer in the perfect 2D limit was successfully realized, for the first time, by the well-defined chemical strategy based on the bottom-up process. The most striking evidence was made from Cs-high resolution transmission electron microscopy measurements by observing directly the atomic structure of g-CN unit cell, which was again supported by the corresponding high resolution transmission electron microscopy image simulation results. We demonstrated that the newly prepared g-CN monolayer showed outstanding photocatalytic activity for HO generation as well as excellent electrocatalytic activity for oxygen reduction reaction.

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The five oligonucleotide primers (oligo-primers) turned out a total of 335 fragments (FMs) (52.9%) in the blue crab () group alpha and 298 FMs (47.1%) in the crab group beta, with the FM scales range varying from 100 bp to 2,000 bp.

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The probing of fundamental photophysics is a key prerequisite for the construction of diverse optoelectronic devices and circuits. To date, though, photocarrier dynamics in 2D materials remains unclear, plagued primarily by two issues: a large exciton binding energy, and the lack of a suitable system that enables the manipulation of excitons. Here, a WSe -based phototransistor with an asymmetric split-gate configuration is demonstrated, which is named the "asymmetry field-effect phototransistor" (AFEPT).

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Article Synopsis
  • - The radix (Licorice) is widely used in Asian medicine for ailments like asthma, coughs, and fatigue, with a new variety called Wongam (WG) developed in Korea showing promising effects but lacking information on its safety.
  • - A study conducted on Sprague-Dawley rats tested the toxicity of WG through both single and repeated oral doses, revealing no significant harmful effects or deaths at levels up to 5000 mg/kg.
  • - The findings indicate a no-observed-adverse-effect level (NOAEL) for WG exceeding 5000 mg/kg/day, with no identifiable target organs in the test subjects, suggesting overall safety for this extract.
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Article Synopsis
  • Humans use a combination of stimulus-response systems and conscious responses to adapt to changes in their environment and tackle external stimuli.
  • This paper introduces an artificial version of this system, which mimics human responses through components like visual receptors, synapses, and neuron circuits.
  • The research highlights how this artificial system learns from repeated stimuli to improve response times, potentially paving the way for advancements in AI-based organs for individuals with neurological disorders.
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Quercetin is a well-known antioxidant and a plant polyphenolic of flavonoid group found in many fruits, leaves, and vegetables. Propionibacterium acnes is a key skin pathogen involved in the progression of acne inflammation. Although quercetin has been applied to treat various inflammatory diseases, the effects of quercetin on P.

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The nature of repetitive learning and oblivion of memory enables humans to effectively manage vast amounts of memory by prioritizing information for long-term storage. Inspired by the memorization process of the human brain, an artificial synaptic array is presented, which mimics the biological memorization process by replicating Ebbinghaus' forgetting curve. To construct the artificial synaptic array, signal-transmitting access transistors and artificial synaptic memory transistors are designed using indium-gallium-zinc-oxide and poly(3-hexylthiophene), respectively.

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The limitation on signal processes implementable using conventional semiconductor circuits based on electric signals necessitates a revolutionary change in device structures such that they can exploit photons or light. Herein, we introduce optoelectric logic circuits that convert optical signals with different wavelengths corresponding to different colors into binary electric signals. Such circuits are assembled using unit devices in which the electric current through the semiconductor channel is effectively gated by lights of different colors.

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Heterojunction structures using 2D materials are promising building blocks for electronic and optoelectronic devices. The limitations of conventional silicon photodetectors and energy devices are able to be overcome by exploiting quantum tunneling and adjusting charge balance in 2D p-n and n-n junctions. Enhanced photoresponsivity in 2D heterojunction devices can be obtained with WSe and BP as p-type semiconductors and MoS and WS as n-type semiconductors.

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To improve the industrial use of health-functional materials based on edible insects, the objective of this study was to establish optimal conditions for improving the quality of larval (PBSL) hydrolysates. PBSL was extracted using four methodologies: atmospheric pressure 50 °C-water extraction, atmospheric pressure 95 °C-water extraction, atmospheric pressure 50 °C-water enzymatic hydrolysis, and enzyme treatment under high pressure (HPE). The quality characteristics of soluble solid content, extraction yield, total protein content, protein yield, protein content with low molecular weight (LMW) (< 1kD), and the amino acid composition of hydrolysates were compared based on the different methods.

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Besides its unprecedented physical and chemical characteristics, graphene is also well known for its formidable potential of being a next-generation device material. Work function (WF) of graphene is a crucial factor in the fabrication of graphene-based electronic devices because it determines the energy band alignment and whether the contact in the interface is Ohmic or Schottky. Tuning of graphene WF, therefore, is strongly demanded in many types of electronic and optoelectronic devices.

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Xanthone is a phenolic compound found in a few higher plant families; it has a variety of biological activities, including antioxidant, anti-inflammatory, and anticancer properties. However, the molecular and cellular mechanisms underlying the activity of xanthone in allergic contact dermatitis (ACD) remain to be explored. Therefore, this study aimed to investigate the regulatory effects of xanthone in ACD in human keratinocytes (HaCaT cell), and human mast cell line (HMC-1 cell) in vitro and in an experimental murine model.

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This paper demonstrates, for the first time, wafer-scale graphene/MoS heterostructures prepared by chemical vapor deposition (CVD) and their application in vertical transistors and logic gates. A CVD-grown bulk MoS layer is utilized as the vertical channel, whereas CVD-grown monolayer graphene is used as the tunable work-function electrode. The short vertical channel of the transistor is formed by sandwiching bulk MoS between the bottom indium tin oxide (ITO, drain electrode) and the top graphene (source electrode).

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This paper introduces a strategy to modulate a Schottky barrier formed at a graphene-semiconductor heterojunction. The modulation is performed by controlling the work function of graphene from a gate that is placed laterally away from the graphene-semiconductor junction, which we refer to as the remote gating of a Schottky barrier. The remote gating relies on the sensitive work function of graphene, whose local variation induced by locally applied field effect affects the change in the work function of the entire material.

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Many scientific and engineering efforts have been made to realize graphene electronics by fully utilizing intrinsic properties of ideal graphene for last decades. The most technical huddles come from the absence of wafer-scale graphene with a single-crystallinity on dielectric substrates. Here, we report an epitaxial growth of single-crystalline monolayer graphene directly on a single-crystalline dielectric SiON-SiC(0001) with a full coverage via epitaxial chemical vapor deposition (CVD) without metal catalyst.

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