Publications by authors named "Younggeun Lee"

Next-generation 6G communication holds the potential to revolutionize data transfer, enabling the realization of eXtended Reality (XR) with enhanced sensory experiences. To achieve this, advanced components such as high-performance intensity/phase modulators, waveguides, multiplexers, splitters, combiners, and filters operating in terahertz (THz) regime, specifically within the frequency range of 0.1-1 THz, are essential.

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Article Synopsis
  • * Researchers developed a method to convert cotton fabric into laser-induced graphene (LIG), which has excellent light absorption properties and can efficiently convert solar energy into heat.
  • * A new 3D LIG evaporator for solar-powered desalination shows impressive performance with high water evaporation rates and efficiency, offering a sustainable solution to tackle water scarcity challenges.
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Garnet-type LiLaZrTaO (LLZTO) is regarded as a highly competitive next-generation solid-state electrolyte for all-solid-state lithium batteries owing to reliable safety, a wide electrochemical operation window of 0-6 V versus Li/Li, and a superior stability against Li metal. Nevertheless, insufficient interface contacts caused by pores, along with Li dendrite growth at these voids and grain boundary regions, have hindered their commercial application. Herein, we suggest a method to produce high-quality LLZTO using LiAlO (LAO) as a chemical additive that leads to an improved microstructure with larger grain size (∼25 μm), a high relative density (∼96%), lower porosity (∼3.

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Rechargeable batteries that can operate at elevated temperatures (>70 °C) with high energy density are long-awaited for industrial applications including mining, grid stabilization, naval, aerospace, and medical devices. However, the safety, cycle life, energy density, and cost of the available high-temperature battery technologies remain an obstacle primarily owing to the limited electrolyte options available. We introduce a flame-retardant electrolyte that can enable stable battery cycling at 100 °C by incorporating triacetin into the electrolyte system.

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Based on the behavioral theory of the firm, we research how performance feedback influences the formation of CEOs' passion. We articulate that previous performance directly increases CEOs' passion. Specifically, positive affective outcomes (performance above aspiration-level) advance CEOs' positive feelings and motivation toward the domains of success (obsessive passion).

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Previous research has mainly focused on the cognitive-based theory of planned behavior (TPB) model to predict entrepreneurial intentions. However, given the close relationship between cognition and emotion, researchers may need to pay more attention to how emotional reactions help predict entrepreneurial intentions. To fill this gap, we apply both cognitive (i.

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Personal wearable devices are considered important in advanced healthcare, military, and sports applications. Among them, e-textiles are the best candidates because of their intrinsic conformability without any additional device installation. However, e-textile manufacturing to date has a high process complexity and low design flexibility.

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The realization of hybrid optics could be one of the best ways to fulfill the technological requirements of compact, light-weight, and multi-functional optical systems for modern industries. Planar diffractive lens (PDL) such as diffractive lenses, photonsieves, and metasurfaces can be patterned on ultra-thin flexible and stretchable substrates and be conformally attached on top of arbitrarily shaped surfaces. In this review, we introduce recent research works addressed to the design and manufacturing of ultra-thin graphene optics, which will open new markets in compact and light-weight optics for next-generation endoscopic brain imaging, space internet, real-time surface profilometry, and multi-functional mobile phones.

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In this paper, we examine the relationship between entrepreneurship education and entrepreneurial passion. Despite the advancement of entrepreneurship education literature and the increasing focus on entrepreneurship education in business schools, we lack empirical exploration on how entrepreneurship education can impact students' passion for founding new organizations. We hypothesize that students who take entrepreneurship classes would develop high levels of founding passion due to a great perception of skills and abilities that increase positive emotions and decrease negative emotions about the entrepreneurship process.

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Cleaning-in-place (CIP) is a representative fouling management process from which the filtration performances of fouled membranes can be recovered. However, CIP can cause significant inefficiency in water production because frequent system restabilization is necessary for cleaning processes. This study applied a newly developed on-line cleaning agent (OCA, a feed water additive for fouling mitigation), to reduce the number of CIP by enhancing water productivity.

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The rapid expansion of the development of the electrochemical capacitor appliance and its industry areas has created the need for long cycling stability of over 30 000 cycles along with an ultrafast performance (referred to as ultrafast longevity). In recent years, zinc-ion hybrid supercapacitors (ZICs) are considered to be emerging energy storage applications thanks to their high specific capacity and remarkable cycling stability. However, ZICs still face serious challenges in overcoming the ultrafast performance and lifetime limitations related to the cathode materials, activated carbon (AC), due to inadequate electrical properties and poor wettability between the electrolyte and the electrode, which cause reductions in specific capacity and lifetime rapidly at high current densities during cycling.

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Article Synopsis
  • Researchers developed a new method for patterning polydimethylsiloxane (PDMS) into complex shapes using a technique called laser pyrolysis, aiming to improve upon traditional costly photolithography processes.
  • This new approach transforms PDMS into removable silicon carbide through a series of laser-guided photothermal pyrolysis, resulting in better surface quality compared to conventional methods.
  • The technique allows for the rapid creation of high-quality 2D and 3D structures in under an hour, enabling the development of advanced microfluidic devices and organ-on-a-chip prototypes for various technological applications.
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Laser-induced forward transfer (LIFT) and selective laser sintering (SLS) are two distinct laser processes that can be applied to metal nanoparticle (NP) ink for the fabrication of a conductive layer on various substrates. A pulsed laser and a continuous-wave (CW) laser are utilized respectively in the conventional LIFT and SLS processes; however, in this study, CW laser-induced transfer of the metal NP is proposed to achieve simultaneous sintering and transfer of the metal NP to a wide range of polymer substrates. At the optimum laser parameters, it was shown that a high-quality uniform metal conductor was created on the acceptor substrate while the metal NP was sharply detached from the donor substrate, and we anticipate that such an asymmetric transfer phenomenon is related to the difference in the adhesion strengths.

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Selective laser sintering of metal nanoparticle ink is an attractive technology for the creation of metal layers at the microscale without any vacuum deposition process, yet its application to elastomer substrates has remained a highly challenging task. To address this issue, we introduced the shear-assisted laser transfer of metal nanoparticle ink by utilizing the difference in thermal expansion coefficients between the elastomer and the target metal electrode. The laser was focused and scanned across the absorbing metal nanoparticle ink layer that was in conformal contact with the elastomer with a high thermal expansion coefficient.

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Selective laser sintering of metal nanoparticle ink is a low-temperature and non-vacuum technique developed for the fabrication of patterned metal layer on arbitrary substrates, but its application to a metal layer composed of large metal area with small voids is very much limited due to the increase in scanning time proportional to the metal pattern density. For the facile manufacturing of such metal layer, we introduce micropatterning of metal nanoparticle ink based on laser-induced thermocapillary flow as a complementary process to the previous selective laser sintering process for metal nanoparticle ink. By harnessing the shear flow of the solvent at large temperature gradient, the metal nanoparticles are selectively pushed away from the scanning path to create metal nanoparticle free trenches.

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Ethnopharmacological Relevance: The giant butterbur Petasites japonicus is used to treat asthma and allergic diseases in traditional Korean, Japanese, and Chinese medicine.

Aim Of The Study: To elucidate the anti-allergic effect of Petasites genus, we studied effects of several compounds from Petasites japonicus leaves and found a novel bakkenolide-type sesquiterpine. In the present study, anti-allergic and anti-inflammatory effects of the new compound was examined using in vivo and in vitro experiments.

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Aim Of The Study: In Oriental countries, the dried fruits of Schisandra chinensis are extensively used in traditional medicine to treat asthma, gonorrhea, and other diseases. Recently, α-cubebenoate was isolated as an anti-inflammatory component from Schisandra chinensis. In the present study, the authors examined the anti-allergic effect of α-cubebenoate using in vivo and in vitro experiments.

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To explore the anti-allergic and anti-inflammatory effects of extracts of Petasites genus, we studied the effects of s-petasin, a major sesquiterpene from Petasites formosanus (a butterbur species) on asthma and peritonitis models. In an ovalbumin-induced mouse asthma model, s-petasin significantly inhibited the accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar fluids. S-petasin inhibited the antigen-induced degranulation of β-hexosamidase but did not inhibit intracellular Ca(2+) increase in RBL-2H3 mast cells.

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Aims Of The Study: Extracts of Schisandra chinensis have been used as an anti-fatigue and tonic agent. Because chronic fatigue syndrome is related to inflammatory and oxidative stress, we assessed whether Schisandra chinensis has anti-inflammatory constituents and studied the effect of a novel α-cubebenoate isolated from Schisandra chinensis.

Materials And Methods: α-Cubebenoate was isolated from an extract of Schisandra chinensis fruits.

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Background: Mammalian bite injuries create a public health problem because of their frequency, potential severity, and increasing number. Some researchers have performed fragmentary analyses of bite wounds caused by certain mammalian species. However, little practical information is available concerning serious mammalian bite wounds that require hospitalization and intensive wound management.

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Aims Of The Study: To elucidate the anti-allergic and anti-inflammatory effects of Petasites genus, we studied the effects of several compounds isolated from Petasites japonicas leaves.

Materials And Methods: Bakkenolide B was isolated from Petasites japonicus leaves. Antigen-induced degranulation was measured in RBL-2H3 mast cells by measuring β-hexosamidase activity.

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