검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 4,140

        1.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구를 통해 미기록종 Acronicta gigasa (큰뿔무늬저녁나방, 신칭)를 한국에 최초로 보고한다. 이 종에 대한 진단과 분류학적 기재문을 작성 하였고, 성충과 생식기 도해사진을 함께 제공하였다.
        4,000원
        2.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We aimed to evaluate the effectiveness of ensemble optimal interpolation (EnOI) in improving the analysis of significant wave height (SWH) within wave models using satellite-derived SWH data. Satellite observations revealed higher SWH in mid-latitude regions (30o to 60o in both hemispheres) due to stronger winds, whereas equatorial and coastal areas exhibited lower wave heights, attributed to calmer winds and land interactions. Root mean square error (RMSE) analysis of the control experiment without data assimilation revealed significant discrepancies in high-latitude areas, underscoring the need for enhanced analysis techniques. Data assimilation experiments demonstrated substantial RMSE reductions, particularly in high-latitude regions, underscoring the effectiveness of the technique in enhancing the quality of analysis fields. Sensitivity experiments with varying ensemble sizes showed modest global improvements in analysis fields with larger ensembles. Sensitivity experiments based on different decorrelation length scales demonstrated significant RMSE improvements at larger scales, particularly in the Southern Ocean and Northwest Pacific. However, some areas exhibited slight RMSE increases, suggesting the need for region-specific tuning of assimilation parameters. Reducing the observation error covariance improved analysis quality in certain regions, including the equator, but generally degraded it in others. Rescaling background error covariance (BEC) resulted in overall improvements in analysis fields, though sensitivity to regional variability persisted. These findings underscore the importance of data assimilation, parameter tuning, and BEC rescaling in enhancing the quality and reliability of wave analysis fields, emphasizing the necessity of region-specific adjustments to optimize assimilation performance. These insights are valuable for understanding ocean dynamics, improving navigation, and supporting coastal management practices.
        4,600원
        3.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 급부상한 생성형 AI는 현실적인 이미지, 텍스트, 음악 및 가상 환경 등을 만들어내는 능력 에 기반하여 엔터테인먼트, 디자인, 의료 및 교육 분야 등 다양한 산업 분야에 근본적인 변화를 가 져올 혁신 동력으로서 주목받고 있다. 오픈AI 등을 중심으로 한 글로벌 빅테크 기업들은 막강한 자 본력을 바탕으로 이 분야의 기술의 고도화와 함께 산업 생태계를 빠르게 구축하며 선도적인 지위를 굳히고 있어 한국의 생성형 AI 산업의 국가경쟁력 강화가 시급하다고 할 수 있다. 본 연구는 국가 경쟁력을 설명하는 Porter의 다이아몬드 모형에 기반해 한국의 생성형 AI 경쟁력에 영향을 미치는 다양한 요인들을 분석하여 한국의 생성형 AI 산업의 성장과 혁신을 육성하기 위한 기업의 전략적 방안과 정부의 정책적 방향성을 다음과 같이 제시하였다. 연구 결과 생성형 AI 관련 기업들의 투자 활동이 응용프로그램 개발을 우선시하고 있는 것으로 나타나 정부는 근본적인 기술 혁신 분야에 R&D 지원에 나서야 함을 알 수 있었다. 또한 기업 사용자들의 생성형 AI 수요가 제한적임에 따라 다양한 관련 교육 프로그램을 개발하고 맞춤 솔루션을 제공해야하며 개인 사용자들간의 디지털 격 차를 해소하는 정책적 노력이 필요하다는 것을 보여주었다. 생성형 AI 유관 산업 육성을 위해, 기 술경쟁력 강화와 인재 육성이 필요하고, 이와 더불어 생성형 AI 산업 에코시스템 내의 기업간 협력 을 촉진하기 위해 정부의 역할이 중요하다는 것을 확인할 수 있었다.
        6,900원
        4.
        2024.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        AR (alkali resistant)-glass fibers were developed to provide better alkali resistance, but there is currently no research on AR-glass fiber manufacturing. In this study, we fabricated glass fiber from AR-glass using a continuous spinning process with 40 wt% refused coal ore. To confirm the melting properties of the marble glass, raw material was put into a (platinum) Pt crucible and melted at temperatures up to 1,650 °C for 2 h and then annealed. To confirm the transparent clear marble glass, visible transmittance was measured and the fiber spinning condition was investigated by high temperature viscosity measurement. A change in diameter was observed according to winding speed in the range of 100 to 700 rpm. We also checked the change in diameter as a function of fiberizing temperature in the range of 1,240 to 1,340 °C. As winding speed increased at constant temperature, fiber diameter tended to decrease. However, at fiberizing temperature at constant winding speed, fiber diameter tended to increase. The properties of the prepared spinning fibers were confirmed by optical microscope, tensile strength, modulus and alkali-resistance tests.
        4,000원
        5.
        2024.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        많은 연구에 따르면 Tenebrio molitor은 유충 단계에서 플라스틱을 섭취할 수 있다고 보고되었다. 이 연구의 목적은 T. molitor 유충의 성장과 발달에 발포폴리스티렌 섭취가 미치는 영향을 조사하는 것이다. 밀기울을 섭취한 유충의 성장률은 발포폴리스티렌을 섭취한 유충의 성장률보다 더 좋았고(p < 0.001) 발포폴리스티렌을 섭취한 유 충의 번데기로 전환되는 기간은 밀기울을 섭취한 유충의 번데기로 전환되는 기간보다 더 빨랐다(p < 0.001). 하지만 두 처리구간 생존율은 유의미한 차이가 없었다(p = 0.786). 이 결과에 따르면 발포폴리스티렌을 섭취한 유충은 체중 감소와 짧은 발육기간이 특징이지만 생존하는 것에는 문제가 없었다. 따라서 우리는 T. molitor가 플라스틱 폐기물 의 지속 가능하고 친환경적인 제거를 위한 주요 자원이라는 결론을 내렸다.
        4,000원
        13.
        2024.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Carbon fusion is important to understand the late stages in the evolution of a massive star. Astronomically interesting energy ranges for the 12C+12C reactions have been, however, poorly constrained by experiments. Theoretical studies on stellar evolution have relied on reaction rates that are extrapolated from those measured in higher energies. In this work, we update the carbon fusion reaction rates by fitting the astrophysical S-factor data obtained from direct measurements based on the Fowler, Caughlan, & Zimmerman (1975) formula. We examine the evolution of a 20M⊙ star with the updated 12C+12C reaction rates performing simulations with the MESA (Modules for Experiments for Stellar Astrophysics) code. Between 0.5 and 1 GK, the updated reaction rates are 0.35 to 0.5 times less than the rates suggested by Caughlan & Fowler (1988). The updated rates result in the increase of core temperature by about 7% and of the neutrino cooling by about a factor of three. Moreover, the carbon-burning lifetime is reduced by a factor of 2.7. The updated carbon fusion reaction rates lead to some changes in the details of the stellar evolution model, their impact seems relatively minor compared to other uncertain physical factors like convection, overshooting, rotation, and mass-loss history. The astrophysical S-factor measurements in lower energies have large errors below the Coulomb barrier. More precise measurements in lower energies for the carbon burning would be useful to improve our study and to understand the evolution of a massive star.
        4,000원
        14.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, polyimide (PI)-based activated carbon fibers (ACFs) were prepared for application as electrode materials in electric double-layer capacitors by varying the steam activation time for the PI fiber prepared under identical cross-linking conditions. The surface morphology and microcrystal structural characteristics of the prepared PI-ACFs were observed by field-emission scanning electron microscopy and X-ray diffractometry, respectively. The textural properties (specific surface area, pore volume, and pore size distribution) of the ACFs were calculated using the Brunauer–Emmett–Teller, Barrett–Joyner–Halenda, and non-local density functional theory equations based on N2/ 77 K adsorption isotherm curve measurements. From the results, the specific surface area and total pore volume of PI-ACFs were determined to be 760–1550 m2/ g and 0.36–1.03 cm3/ g, respectively. It was confirmed that the specific surface area and total pore volume tended to continuously increase with the activation time. As for the electrochemical properties of PI-ACFs, the specific capacitance increased from 9.96 to 78.64 F/g owing to the developed specific surface area as the activation time increased.
        4,600원
        15.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Because plastics are cheap and light, their use is indispensable in our daily lives. However, the extensive use of plastics causes the disposal issue. Among various disposal processes, plastic recycling is of great attention because of minimizing waste and harmful byproducts. Herein, we recycle the most popular thermoplastic materials, high-density and low-density polyethylene, producing the anode materials for the Li-ion batteries. The electrochemical properties of the as-recycled soft carbon are investigated to study the energy storage capability as the anode of Li-ion batteries. Our work demonstrates the soft carbon recycled from plastic wastes is a promising anode material.
        4,000원
        16.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study prepares highly porous carbon (c-fPI) for lithium-ion battery anode that starts from the synthesis of fluorinated polyimide (fPI) via a step polymerization, followed by carbonization. During the carbonization of fPI, the decomposition of fPI releases gases which are particularly from fluorine-containing moiety (–CF3) of fPI, creating well-defined microporous structure with small graphitic regions and a high specific surface area of 934.35 m2 g− 1. In particular, the graphitic region of c-fPI enables lithiation–delithiation processes and the high surface area can accommodate charges at electrolyte/electrode interface during charge–discharge, both of which contribute electrochemical performances. As a result, c-fPI shows high specific capacity of 248 mAh g− 1 at 25 mA g− 1, good rate-retention performance, and considerable cycle stability for at least 300 charge–discharge cycles. The concept of using a polymeric precursor (fPI), capable of forming considerable pores during carbonization is suitable for the use in various applications, particularly in energy storage systems, advancing materials science and energy technologies.
        4,000원
        17.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-entropy alloys (HEAs) have been reported to have better properties than conventional materials; however, they are more expensive due to the high cost of their main components. Therefore, research is needed to reduce manufacturing costs. In this study, CoCrFeMnNi HEAs were prepared using metal injection molding (MIM), which is a powder metallurgy process that involves less material waste than machining process. Although the MIM-processed samples were in the face-centered cubic (FCC) phase, porosity remained after sintering at 1200°C, 1250°C, and 1275°C. In this study, the hot isostatic pressing (HIP) process, which considers both temperature (1150°C) and pressure (150 MPa), was adopted to improve the quality of the MIM samples. Although the hardness of the HIP-treated samples decreased slightly and the Mn composition was significantly reduced, the process effectively eliminated many pores that remained after the 1275°C MIM process. The HIP process can improve the quality of the alloy.
        4,300원
        18.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The development of thermoelectric (TE) materials to replace Bi2Te3 alloys is emerging as a hot issue with the potential for wider practical applications. In particular, layered Zintl-phase materials, which can appropriately control carrier and phonon transport behaviors, are being considered as promising candidates. However, limited data have been reported on the thermoelectric properties of metal-Sb materials that can be transformed into layered materials through the insertion of cations. In this study, we synthesized FeSb and MnSb, which are used as base materials for advanced thermoelectric materials. They were confirmed as single-phase materials by analyzing X-ray diffraction patterns. Based on electrical conductivity, the Seebeck coefficient, and thermal conductivity of both materials characterized as a function of temperature, the zT values of MnSb and FeSb were calculated to be 0.00119 and 0.00026, respectively. These properties provide a fundamental data for developing layered Zintl-phase materials with alkali/alkaline earth metal insertions.
        4,000원
        19.
        2024.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Vitrification, one of the most promising solidification processes for various materials, has been applied to radioactive waste to improve its disposal stability and reduce its volume. Because the thermal decomposition of dry active waste (DAW) significantly reduces its volume, the volume reduction factor of DAW vitrification is high. The KHNP developed the optimal glass composition for the vitrification of DAW. Since vitrification offers a high-volume reduction ratio, it is expected that disposal costs could be greatly reduced by the use of such technology. The DG-2 glass composition was developed to vitrify DAW. During the maintenance of nuclear power plants, metals containing paper, clothes, and wood are generated. ZrO2 and HfO2 are generally considered to be network-formers in borosilicate-based glasses. In this study, a feasibility study of vitrification for DAW that contains metal particulates is conducted to understand the applicability of this process under various conditions. The physicochemical properties are characterized to assess the applicability of candidate glass compositions.
        4,200원
        20.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Human bitter taste-sensing type 2 receptors (hTAS2Rs) are expressed in various human tissues and may be associated with various cell signaling pathways, cell progression, and cell physiology in each tissue. hTAS2Rs can be a potential drug target because it is also expressed in some cancer cells. Xanthorrhizol (XNT) has various biological activities, such as anticancer, antimicrobial, anti-inflammatory, and antioxidant. XNT produces a bitter taste, but the specific hTAS2R activated is unknown, and the hTAS2R-mediated effect of XNT on cancer cells has not been studied. This study discovered the target receptor of XNT among 25 hTAS2Rs and confirmed the possibility of the hTAS2R-mediated inhibition of cancer cell proliferation. XNT activated only one receptor, hTAS2R38 (EC50=1.606±0.021 g/mL), and its activity was inhibited by probenecid, a hTAS2R38 antagonist. When HepG2 and MCF-7 cells were treated with XNT or phenylthiocarbamide (PTC), a known hTAS2R38 agonist, both chemicals inhibited cancer cell proliferation. XNT targets the human bitter taste receptor TAS2R38 and inhibits the proliferation of HepG2 and MCF-7 cells mediated by TAS2R38. This suggests that TAS2R38 may be a new target for disease treatment and a potential new factor for drug development.
        4,000원
        1 2 3 4 5