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        검색결과 111

        1.
        2026.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the meteorological characteristics and mechanisms of three distinct heavy snowfall events that occurred over the central Korean Peninsula on November 27, 2024, December 15, 2024, and March 18, 2025. Satellite imagery, total precipitable water, integrated vapor transport, and wind and pressure field data revealed that the November 27, 2024 event represented a compound case wherein strong moisture transport from the southwestern sea combined with a cut-off low, leading to the development of an atmospheric river (AR), synoptic-scale ascent, and countrywide heavy snowfall. In contrast, the December 15 2024 event exhibited a typical lake-effect snowfall pattern characterized by weak AR activity and a dominant localized moisture supply from the Yellow Sea, resulting in short-lived and spatially confined snowfall. The March 18, 2025 event was a mixed cycloniclake-effect case triggered by the interaction between mid-latitude moisture transported by southwesterly winds and an upper-level low, producing significant snowfall over the Seoul metropolitan and Yeongdong regions. These differences arise from variations in AR strength, lakeeffect processes, and cyclonic development, whereas all three events shared enhanced thermal instability, a moisture supply associated with a large SST850 hPa temperature difference (ΔT>10oC), and a prevailing northwesterly flow. These specific cases show that heavy snowfall intensity and duration are closely linked to sequential interactions between large-scale AR processes, regional lake effects, and cyclonic mechanisms. Overall, this study suggests that an increased AR frequency under climate change scenarios may increase the risk of extreme snowfall, thereby contributing to improved weather forecasting and disaster preparedness strategies.
        6,400원
        2.
        2026.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present the result from a comprehensive laboratory and on-sky characterization of the commercial spectrograph system consisting of a PIXIS 1300BX charge-coupled device (CCD) camera and an IsoPlane 320A spectrograph as part of the preparation of the forthcoming all-sky spectroscopic survey of nearby galaxies (A-SPEC). In the laboratory, we have quantified readout noise, dark current, gain, and full-well capacity via bias, dark, and photon transfer curve analysis at all acquisition modes. To do that, we have developed a gradient correction technique to address row-dependent signal gradients in the image, which are caused by the shutter-less condition of our CCD camera test setup. The technique successfully reproduces the values in the manufacturer specifications. We also have measured quantum efficiency exceeding 80% from 400–800 nm and ≳ 90% between 450–750 nm, with sub-second persistence decay, making it ideal for rapid, multi-object spectroscopy. Using a set of diffraction gratings (150, 300, and 600 grmm−1), we have evaluated the spatial separability of multiple spectra and spectral resolution. We have conducted a test observation with this spectrograph system at the Seoul National University Astronomical Observatory (SAO) 1 m telescope and successfully demonstrated its capability of multi-object spectroscopy with moderate resolution of R ≈ 600–2600. We release all Python codes for the test and recipes to facilitate further instrument evaluations.
        5,700원
        3.
        2025.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is challenging to treat canine brucellosis due to the immune evading and stealthy characteristic of the causative bacteria, Brucella (B.) canis. Gold nanoparticle aptamer (AuNP-Apt) conjugated antimicrobial peptide (AMP) is a promising alternative to antibiotics for various bacterial infections. However, the toxicity of AuNP-Apt has been variable throughout research, and the in vivo toxic mechanism has not been fully elucidated. This study evaluated the therapeutic potential against B. canis, and the toxicity of AuNP-Apt conjugated antimicrobial peptide, RW-BP100 (AuNP-AptHis-RW-BP100His), in a mouse model. Intravenous (IV) treatment with AuNP-AptHis-RW-BP100His reduced the bacteria burden and histopathologic lesions. The IV treatment also induced CD4+ T cell differentiation and modulated serum cytokine levels. However, high-dose AuNP-Apt was lethal, resulting in tissue accumulation and vessel embolism. Therefore, AuNP-AptHis-RW-BP100His is a promising therapeutic agent for B. canis treatment, but due to its toxicity, further studies are needed for its utilization in clinical practice.
        4,000원
        6.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This review examines the microstructural and mechanical properties of a Ti-6Al-4V alloy produced by wrought processing and powder metallurgy (PM), specifically laser powder bed fusion (LPBF) and hot isostatic pressing. Wrought methods, such as forging and rolling, create equiaxed alpha (α) and beta (β) grain structures with balanced properties, which are ideal for fatigue resistance. In contrast, PM methods, particularly LPBF, often yield a martensitic α′ structure with high microhardness, enabling complex geometries but requiring post-processing to improve its properties and reduce stress. The study evaluated the effects of processing parameters on grain size, phase distribution, and material characteristics, guiding the choice of fabrication techniques for optimizing Ti-6Al-4V performance in aerospace, biomedical, and automotive applications. The analysis emphasizes tailored processing to meet advanced engineering demands.
        4,000원
        7.
        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
        8.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Throughfall (TF)—as a diffusive hydrological water flux—significantly affects ecohydrological and biogeochemical processes within forest ecosystems. Recent investigations have revealed the impact on TF generation processes within unmanaged coniferous plantations of under-canopy structures, particularly those laden with dead branches, as well as upper-canopy structures. However, spatiotemporal variations in TF in such plantations remain unexplored. We investigated these variations in TF in a 33-year-old unmanaged Japanese cypress (Chamaecyparis obtusa Endl.) plantation, laden with dead branches, with a high stand density (SD) of 2,500 stems ha−1. Over a two-year period (May 2017 to May 2019), we conducted weekly TF measurements using 28 manual-type TF collectors. We compared the present TF ratio and canopy water storage capacity (S) with those of previous investigations conducted on Japanese cypress plantations. Moreover, we assessed key indices contributing to spatiotemporal TF variations (canopy cover: CC and distance to the nearest stem: TFd) and potentially influential dead branch indices (number of dead branches: TFdb and vertical spacing length on a stem: TFs) to elucidate TF spatial patterns. The results showed that the TF ratio was notably lower than that in previous studies (n = 13), with SD (r = –0.92, p < 0.001) and S (r = –0.87, p < 0.001) emerging as key influential factors among other stand-structure parameters. Spatial TF patterns exhibited a decreasing trend as the gross rainfall (GR) increased. Temporal stability was not significantly associated with CC (r = 0.120, p = 0.544), TFd (r = 0.068, p = 0.731), TFdb (r = 0.211, p = 0.281), or TFs (r = 0.206, p = 0.292) for any of the TF collectors. These findings underscore the important role of GR in determining the spatial variation of TF. Collectively, our results contribute to an enhanced understanding of TF spatiotemporal heterogeneity in unmanaged Japanese cypress plantations with dead branches.
        4,600원
        11.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to calculate the damage of Italian ryegrass (IRG) by abnormal climate using machine learning and present the damage through the map. The IRG data collected 1,384. The climate data was collected from the Korea Meteorological Administration Meteorological data open portal.The machine learning model called xDeepFM was used to detect IRG damage. The damage was calculated using climate data from the Automated Synoptic Observing System (95 sites) by machine learning. The calculation of damage was the difference between the Dry matter yield (DMY)normal and DMYabnormal. The normal climate was set as the 40-year of climate data according to the year of IRG data (1986~2020). The level of abnormal climate was set as a multiple of the standard deviation applying the World Meteorological Organization (WMO) standard. The DMYnormal was ranged from 5,678 to 15,188 kg/ha. The damage of IRG differed according to region and level of abnormal climate with abnormal temperature, precipitation, and wind speed from -1,380 to 1,176, -3 to 2,465, and -830 to 962 kg/ha, respectively. The maximum damage was 1,176 kg/ha when the abnormal temperature was -2 level (+1.04℃), 2,465 kg/ha when the abnormal precipitation was all level and 962 kg/ha when the abnormal wind speed was -2 level (+1.60 ㎧). The damage calculated through the WMO method was presented as an map using QGIS. There was some blank area because there was no climate data. In order to calculate the damage of blank area, it would be possible to use the automatic weather system (AWS), which provides data from more sites than the automated synoptic observing system (ASOS).
        4,000원
        13.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-entropy alloys (HEAs) are attracting attention because of their excellent properties and functions; however, they are relatively expensive compared with commercial alloys. Therefore, various efforts have been made to reduce the cost of raw materials. In this study, MIM is attempted using coarse equiatomic CoCrFeMnNi HEA powders. The mixing ratio (powder:binder) for HEA feedstock preparation is explored using torque rheometer. The block-shaped green parts are fabricated through a metal injection molding process using feedstock. The thermal debinding conditions are explored by thermogravimetric analysis, and solvent and thermal debinding are performed. It is densified under various sintering conditions considering the melting point of the HEA. The final product, which contains a small amount of non-FCC phase, is manufactured at a sintering temperature of 1250oC.
        4,000원
        18.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to investigate the effect of isolated lactic acid bacteria (LAB) on the quality of high moisture rye silage. Rye forage (Secale cereale L.) was harvested at the heading stage (27.3% of dry matter (DM)) and cut into approximately 3-5 cm lengths. Then, the forage divided into 4 treatments with different inoculants: 1) No additives (CON); 2) Lactobacillus brevis strain 100D8 at a 1.2 x 105 colony-forming unit (cfu)/g of fresh forage (LBR); 3) Leuconostoc holzapfelii strain 5H4 at a 1.0 x 105 cfu/g of fresh forage (LHO); and 4) Mixture of LBR and LHO (1:1 ratio) applied at a 1.0 x 105 cfu/g of fresh forage (MIX). About 3 kg of forage from each treatment was ensiled into a 20 L mini-bucket silo in quadruplicate for 100 days. After silo opening, silage was collected for analyses of chemical compositions, in vitro nutrient digestibilities, fermentation characteristics, and microbial enumerations. The CON silage had the highest concentrations of neutral detergent fiber and acid detergent fiber (p = 0.006; p = 0.008) and a lowest in vitro DM digestibility (p < 0.001). The pH was highest in CON silage, while lowest in LBR and MIX silages (p < 0.001). The concentrations of ammonia-N, lactate, and acetate were highest in LBR silage (p = 0.008; p < 0.001; p < 0.001). Propionate and butyrate concentrations were highest in CON silage (p = 0.004; p < 0.001). The LAB and yeast counts were higher in CON and LHO silages compare to LBR and MIX silages (p < 0.001). However, the mold did not detect in all treatments. Therefore, this study could conclude that L. brevis 100D8 and Leu. holzapfelii strain 5H4 can improve the digestibility and anti-fungal activity of high moisture rye silage.
        4,000원
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