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        검색결과 5,059

        41.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Milky white spots appeared on red bean leaves in a red bean cultivation area located in Jangyeon-myeon, Goesan-gun, Chungbuk Province. After culturing the pathogen in PDA medium, their morphology was observed, and their genes were BLAST-searched in the National Center for Biotechnology Information (NCBI). The pathogen was identified as a fungus called Rhizopus arrhizus. As a result of reinoculating the isolated pathogen on red beans, the same symptoms as those in the isolated leaves occurred. Characteristic colonies of R. arrhizuson PDA medium initially showed a bright color and then changed to dark gray over time, with mostly spherical sporangia. The sporangiospores were spherical or elliptical, mostly irregular, and small in size. Therefore, based on these results, this disease has not yet been reported in red beans and was called red bean brown leaf blight caused by Rhizopus arrhizus A. Fisch (syn. R. oryzae).
        4,000원
        42.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        River estuaries are dynamic and productive ecosystems with high regional biodiversity. Environmental DNA (eDNA) has become a useful approach to assessing biodiversity in aquatic ecosystems. This study was conducted to investigate fish community characteristics and species diversity in two river estuary ecosystems, the Taehwa River and Changwon Stream. We further compared conventional and eDNA metabarcoding analyses of the fish communities. The conventional survey was performed in May, July, and October 2022, while the eDNA analysis was conducted only in May. We observed various fish species with different life histories, including carp, goby, and marine fish. We also found that migratory fish, such as dace Tribolodon hakonensis, sweetfish Plecoglossus altivelis, and eel Auguilla japonica, occurred in the Taehwa River, suggesting high river connectivity. Marine fish species were predominant in the Changwon Stream, as this river is located close to the sea. The diversity indices showed that the Taehwa River generally had higher species richness, evenness, and diversity values than the Changwon Stream. A total of 9-19 species were detected in the conventional survey for the three sites, whereas 11-18 species were found from eDNA analysis. The findings indicate that the sensitivity of eDNA was similar to or higher than that of the conventional method. Our study findings suggest the efficiency and efficacy of eDNA-based fish community monitoring, although with some shortcomings in applying the genetic marker to Korean fish, including no clear-cut distinction for Korean endemic species and/or genetically closely related species groups.
        5,500원
        43.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 중·저준위 방사성폐기물은 영구적 격리를 위해 처분장에 매립하고 있으며 그 위치는 경주에 있다. 이러한 방 사성폐기물의 영구적인 격리를 위한 처분시설은 공학적 방벽과 자연 방벽으로 구성되어 있으며 자연 방벽을 특성을 파악 하기 위하여 한국원자력환경공단에서는 2006년부터 부지특성조사를 수행하였고, 이후 부지감시 및 조사계획에 따른 감시 를 수행하여 부지특성의 변화를 지속적으로 확인하고 있다. 중저준위 방폐장의 수리지화학적 환경은 자연 방벽의 평가를 위해 중요한 요소로 손꼽히고 있으나 동해와 가까운 경주의 지역적 특성상 해수의 영향을 반드시 고려해야 한다. 따라서 본 연구에서는 처분 부지의 지하수 관정 7개 및 관정의 심도별 수질 자료를 취합해 지하수 자료 총 30개를 해수 2개소와 비교 분석하여 수리지화학적 환경을 해석하였다. 분석 자료는 수질 10개 항목(온도, EC, HCO3, Na, K, Ca, Mg, Cl, SO4, SiO2)을 2017년 3분기부터 2022년 3분기까지 총 5년간 20회의 자료를 활용하였다. 특히, EC, HCO3, Na, Cl의 농도 변화 를 통해 연구 지역의 배경 농도 및 관정의 구간별 해수의 영향을 파악하였으며, 시계열 군집 분석을 통해 담수, 기수, 해 수의 분류를 시도하였다. 그 결과, 기존의 모니터링 방법으로는 확인하지 못한 부지내 수리지화학적 변화를 제시하였다.
        4,600원
        44.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate antioxidant and anti-inflammatory activities of perilla(Perilla frutescens L.) seed, flower and leaf according to extraction condition. Perilla seed extracts(PSE), perilla flower extracts(PFE), perilla leaf extracts(PLE) was extracted by stirring extraction (STE, 25°C), shaking extraction (SHE, 80°C), and sonication assisted extraction(SAE, , 25°C) with 94% ethanol, 60% ethanol and distilled water, followed by analysis of total polyphenol and flavonoid and testing radical scavenging activities. The highest total polyphenol content (5.47, 9.36, 38.58 mg gallic acid equivalent/g), total flavonoid content(5.77, 8.62, 46.44 mg catechin equivalent/g), ABTS(10.68, 19.46, 63.56 mg trolox equivalent/g) and DPPH(6.51, 7.69, 79.73 mg trolox equivalent/g) radical scavenging activity of PSE, PFE and PLE was observed in the HWE with 60% ethanol,. Among the three extraction method, SHE provided the best results for yield, polyphenol, flavonoid content of perilla seed, flower, leaf in comparison to STE or SAE. SHE with 60% ethanol of perilla seed, flower, leaf more effectively inhibited secretion of nitric oxide(NO) and pro-inflammatory cytokine in RAW 264.7 macrophage exposed to LPS compared to other extraction solvent and method. Therefore, these extracts obtained from perilla seed, flower, leaf could be used antioxidant and anti-inflammatory ingredients in the food industry.
        4,000원
        45.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The occurrence of eggs and adults of Pochazia shantungensis, Lycorma delicatula, and Lymantria dispar was investigated in 11 cities in the Chungcheongbukdo region. The results showed that the overwintering eggs of P. shantungensis occurred in 24.2% of the region in 2021 and 22.1% in 2022, while adults occurred in 25.2% in 2021 and 24.3% in 2022, indicating the highest occurrence among the pests studied. The occurrence of overwintering eggs of L. delicatula was relatively low, with 2.6% of the region affected in 2021 and 1.9% in 2022. Adult L. delicatula occurred in 3.2% of the region in 2021 and 3.6% in 2022. Overwintering eggs of L. dispar occurred in 4.1% of the area in 2021 and 1.7% in 2022, showing a decreasing tendency compared to the previous year, and their occurrence was only low to middle in terms of the degree of occurrence. Adult L. dispar occurred in 4.6% of the region in 2021 and 2.7% in 2022, showing occurrences that were insignificant compared to L. delicatula. According to a survey of host preferences, both the wintering eggs and adults of P. shantungensis were found in apples and peaches between 2021 and 2022. In both 2021-2022, adult L. delicatula had a high incidence in peaches, apples, and grapes, and winter eggs were the highest in grapes. However, the incidence in apples and peaches was low. A high incidence density of L. dispar moth adults and overwintering eggs was found in apples in both 2021 and 2022.
        4,200원
        46.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Highly safe lithium-ion batteries (LIBs) are required for large-scale applications such as electrical vehicles and energy storage systems. A highly stable cathode is essential for the development of safe LIBs. LiFePO4 is one of the most stable cathodes because of its stable structure and strong bonding between P and O. However, it has a lower energy density than lithium transition metal oxides. To investigate the high energy density of phosphate materials, vanadium phosphates were investigated. Vanadium enables multiple redox reactions as well as high redox potentials. LiVPO4O has two redox reactions (V5+/V4+/V3+) but low electrochemical activity. In this study, LiVPO4O is doped with fluorine to improve its electrochemical activity and increase its operational redox potential. With increasing fluorine content in LiVPO4O1-xFx, the local vanadium structure changed as the vanadium oxidation state changed. In addition, the operating potential increased with increasing fluorine content. Thus, it was confirmed that fluorine doping leads to a strong inductive effect and high operating voltage, which helps improve the energy density of the cathode materials.
        4,000원
        47.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research aimed to examine the effects of grapefruit seed extract (GSE) at various concentrations on the microbial safety and physicochemical characteristics of onion puree (0.01~0.1%). The onion puree was kept at 4℃ for 14 days. The results of the study indicated that the addition of GSE did not cause any significant changes in the sample’s brix degree and viscosity in onion puree (p<0.05). However, as the concentration of GSE increased, the pH level decreased. On the other hand, as GSE was added, the lightness of the onion puree increased, while the redness and yellowness decreased. Compared to pure onion puree, the GSE-incorporated onion puree had higher levels of total flavonoid and total polyphenol content, indicating that it helps to maintain antioxidant activities. Based on the microbial safety test, aerobic bacteria, yeast, and mold were absent until day 14 of storage. In conclusion, the study suggests that the addition of GSE to onion puree increases its antioxidant activity and shelf-life.
        4,200원
        48.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Aluminum alloys, known for their high strength-to-weight ratios and impressive electrical and thermal conductivities, are extensively used in numerous engineering sectors, such as aerospace, automotive, and construction. Recently, significant efforts have been made to develop novel aluminum alloys specifically tailored for additive manufacturing. These new alloys aim to provide an optimal balance between mechanical properties and thermal/ electrical conductivities. In this study, nine combinatorial samples with various alloy compositions were fabricated using direct energy deposition (DED) additive manufacturing by adjusting the feeding speeds of Al6061 alloy and Al-12Si alloy powders. The effects of the alloying elements on the microstructure, electrical conductivity, and hardness were investigated. Generally, as the Si and Cu contents decreased, electrical conductivity increased and hardness decreased, exhibiting trade-off characteristics. However, electrical conductivity and hardness showed an optimal combination when the Si content was adjusted to below 4.5 wt%, which can sufficiently suppress the grain boundary segregation of the α- Si precipitates, and the Cu content was controlled to induce the formation of Al2Cu precipitates.
        4,000원
        49.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Species distribution model (SDM) is used to preserve biodiversity and climate change impact. To evaluate biodiversity, various studies are being conducted to utilize and apply SDM. However, there is insufficient research to provide useful information by identifying the current status and recent trends of SDM research and discussing implications for future research. This study analyzed the trends and flow of academic papers, in the use of SDM, published in academic journals in South Korea and provides basic information that can be used for related research in the future. The current state and trends of SDM research were presented using philological methods and text-mining. The papers on SDM have been published 148 times between 1998 and 2023 with 115 (77.7%) papers published since 2015. MaxEnt model was the most widely used, and plant was the main target species. Most of the publications were related to species distribution and evaluation, and climate change. In text mining, the term ‘Climate change’ emerged as the most frequent keyword and most studies seem to consider biodiversity changes caused by climate change as a topic. In the future, the use of SDM requires several considerations such as selecting the models that are most suitable for various conditions, ensemble models, development of quantitative input variables, and improving the collection system of field survey data. Promoting these methods could help SDM serve as valuable scientific tools for addressing national policy issues like biodiversity conservation and climate change.
        4,600원
        50.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study is to initiated to estimate the impact of mixed traffic flow on expressway section according to the market penetration rate(MPR) of automated vehicles(AVs) using a enhanced intelligent driver model(EIDM). METHODS : To this end, microscopic traffic simulation and EIDM were used to implement mixed traffic flow on basic expressway section and simulation network was calibrated to understand the change of impact in mixed traffic flow due to the MPR of AVs. Additionally, MOEs of mobility aspects such as average speed and travel time were extracted and analyzed. RESULTS : The result of the impact of mobility MOEs by MPR and level of service indicated that 100% MPR of AVs normally affect positive impact on expressway at all level of service. However, it was analyzed that improvements in the level of service from LOS A to C are minimal until the MPR of AVs reaches 75% or higher. CONCLUSIONS : This research shows that impact of MPR of AVs using EIDM of mixed traffic flow on basic expressway. Increasing MPR of AVs affects positive impact on expressway at all level of services. However, MPR from 25% to 75% of AVs in LOS A to C shows minimal impacts. Therefore, to maximize the effectiveness of AVs, appropriate traffic operation and management strategies are necessary.
        4,000원
        51.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 중공사형 이산화탄소 분리막 모듈을 사용하여 수소개질기 배가스로부터 이산화탄소 포집을 목적 으로 한 분리막 공정 최적화 연구를 진행하였다. 랩스케일의 소형 분리막 모듈을 사용하여 혼합기체를 대상으로 이산화탄소 순도 90% 및 회수율 90%을 달성하는 2단 공정 조건을 도출하였다. 막 면적이 정해진 모듈의 분리막 공정에서는 스테이지-컷, 주입부 및 투과부 압력에 따라서 포집 순도 및 회수율이 모두 다르게 나타나기 때문에 운전 조건에 대한 최적화가 필수적이 다. 본 연구에서는 다양한 운전 조건에서 1단 분리막에서 보이는 공정 포집 효율의 한계를 확인하고, 높은 순도와 회수율을 동시에 달성하기 위한 2단 회수 공정을 최적화하였다.
        4,000원
        52.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dissolved organic matter (DOM) is a key component in the biogeochemical cycling in freshwater ecosystem. However, it has been rarely explored, particularly complex river watershed dominated by natural and anthropogenic sources, such as various effluent facility and livestock. The current research developed a new analytical method for TOC/TN (Total Organic Carbon/Total Nitrogen) stable isotope ratio, and distinguish DOM source using stable isotope value (δ13C-DOC) and spectroscopic indices (fluorescence index [FI] and biological index [BIX]). The TOC/TN-IR/MS analytical system was optimized and precision and accuracy were secured using two international standards (IAEA-600 Caffein, IAEA-CH-6 Sucrose). As a result of controlling the instrumental conditions to enable TOC stable isotope analysis even in low-concentration environmental samples (<1 mgC L-1), the minimum detection limit was improved. The 12 potential DOM source were collected from watershed, which includes top-soils, groundwater, plant group (fallen leaves, riparian plants, suspended algae) and effluent group (pig and cow livestock, agricultural land, urban, industry facility, swine facility and wastewater treatment facilities). As a result of comparing characteristics between 12 sources using spectroscopic indices and δ13C-DOC values, it were divided into four groups according to their characteristics as a respective DOM sources. The current study established the TOC/TN stable isotope analyses system for the first time in Korea, and found that spectroscopic indices and δ13C-DOC are very useful tool to trace the origin of organic matter in the aquatic environments through library database.
        4,000원
        53.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To investigate the impact of forestry projects on the carbon stocks of forests, we estimated the carbon stock change of above-ground and soil before and after forestry projects using forest type maps, forestry project information, and soil information. First, we selected six map sheet with large areas and declining age class based on forest type map information. Then, we collected data such as forest type maps, growth coefficients, soil organic matter content, and soil bulk density of the estimated areas to calculate forest carbon storage. As a result, forest carbon stocks decreased by about 34.1~70.0% after forestry projects at all sites. In addition, compared to reference studies, domestic forest soils store less carbon than the above-ground, so it is judged that domestic forest soils have great potential to store more carbon and strategies to increase carbon storage are needed. It was estimated that the amount of carbon stored before forestry projects is about 1.5 times more than after forestry projects. The study estimated that it takes about 27 years for forests to recover to their pre-thinning carbon stocks following forestry projects. Since it takes a long time for forests to recover to their original carbon stocks once their carbon stocks are reduced by physical damage, it is necessary to plan to preserve them as much as possible, especially for highly conservative forests, so that they can maintain their carbon storage function.
        4,000원
        54.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the performances of H2S, NH3, and HCl sensors for real-time monitoring in small emission facilities (4, 5 grades in Korea) were evaluated at high concentration conditions of those gases. And the proper approach for the collection of reliable measurement data by sensors was suggested through finding out the effect on sensor performances according to changes in temperature and humidity (relative humidity, RH) settings. In addition, an assessment on sensor data correction considering the effects produced by environmental settings was conducted. The effects were tested in four different conditions of temperature and humidity. The sensor performances (reproducibility, precision, lower detection limit (LDL), and linearity) were good for all three sensors. The intercept (ADC0) values for all three sensors were good for the changes of temperature and humidity conditions. The variation in the slope value of the NH3 sensor showed the highest value, and this was followed by the HCl, H2S sensors. The results of this study can be helpful for data collection by enabling the more reliable and precise measurements of concentrations measured by sensors.
        4,000원
        55.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We aimed to develop outstanding domestic varieties suitable for both columnar and cylindrical-shape substrates, aiming to replace foreign varieties. and bred a high-quality new strain named ‘Charmjon’, using genetic resources collected from Japan and China. The optimal cultivation temperature for Charmjon’s mycelial growth was found to be 25°C, and its mycelial growth at 15°C and 25°C was superior to the control variety. In terms of mycelial growth characteristics based on the substrate, Charmjon exhibited excellent mycelial strength on PDA medium compared to the control variety. Through columnar and cylindrical-shape substrates cultivation, we assessed the quantity and morphological characteristics of the fruiting bodies. The results confirmed that Charmjon can be produced stably using both cultivation methods, and it showed higher yields and individual weights than the control variety. In addition, the color of the pileus was notably darker, and the shape of the pileus varied depending on the cultivation method. The test of genetic diversity revealed that Charmjon has distinct genetic characteristics compared to the control varieties.
        4,000원
        56.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to identify the major peacekeeping activities that the Korean armed forces has performed from the past to the present. To do this, we collected 692 press releases from the National Defense Daily over the past 20 years and performed topic modeling and social network analysis. As a result of topic modeling analysis, 112 major keywords and 8 topics were derived, and as a result of examining the Korean armed forces's peacekeeping activities based on the topics, 6 major activities and 2 related matters were identified. The six major activities were 'Northeast Asian defense cooperation', 'multinational force activities', 'civil operations', 'defense diplomacy', 'ceasefire monitoring group', and 'pro-Korean activities', and 'general troop deployment' related to troop deployment in general. Next, social network analysis was performed to examine the relationship between keywords and major keywords related to topic decision, and the keywords ‘overseas’, ‘dispatch’, and ‘high level’ were derived as key words in the network. This study is meaningful in that it first examined the topic of the Korean armed forces's peacekeeping activities over the past 20 years by applying big data techniques based on the National Defense Daily, an unstructured document. In addition, it is expected that the derived topics can be used as a basis for exploring the direction of development of Korea's peacekeeping activities in the future.
        5,100원
        57.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Flammulina velutipesis a popular edible mushroom in South Korea, accounting for approximately 30% of the total mushroom export in the country. Despite its significant position in the domestic mushroom industry, approximately 65% of the cultivated F. velutipes are foreign varieties. To secure variety rights and enhance competitiveness in the export market, there is a need to develop domestic varieties with stable production and excellent shelf life. We focused on breeding a new variety called 'Baekwoon' through mon–mon crossing, using 'Baekseung' and an international collection strain (KMCC02260) as parents. Baekwoon exhibited faster mycelial growth rates at 15 °C and 25 °C and higher mycelial growth across four tested media compared to that of the control variety. Under bottle cultivation, Baekwoon had a mycelial cultivation period that was shorter by approximately 2 days compared to that of the control. The yield of Baekwoon was 228.0±10.9 g, 8.3% more than that of the control. Furthermore, Baekwoon displayed distinct morphological features characterized by a larger pileus and thicker stipe compared to that of the control variety. Genetic tests confirmed that Baekwoon is genetically different from both parental strains and the control variety. It is expected that the newly developed F. velutipes variety, Baekwoon, will be evaluated for its adaptation in different regions and actively promoted in the field, ultimately increasing the market share of domestic varieties.
        4,000원
        58.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mushrooms have a unique taste and aroma, so in the processing of mushroom products with other ingredients, a separate pre-processing step is often taken to eliminate the mushroom aroma. In this study, we analyzed the changes in the concentration of volatile compounds according to drying conditions to promote the activation of processing using the fruiting bodies of yellow oyster mushrooms(Pleurotus citrinopileatus) and pink oyster mushrooms(P. djamor). The caps and stipes of yellow oyster and pink oyster mushrooms were separated and freeze-dried at -70oC for 120 hours. Subsequently, they were hot air-dried at temperatures of 40, 50, 60, and 70oC for 24, 24, 16, and 12 hours, respectively. The dried samples were pulverized and quantitatively analyzed by SPME-GC-MS. In the case of yellow oyster mushrooms, the concentration of t-2-nonenal in caps and stipes during freeze-drying was 164.43 g/g d.w. and 174.80 g/g d.w., respectively, whereas during hot air-drying, it significantly decreased to 0.35~3.41 g/g d.w. and 0.98~59.88 g/g d.w. In a similar manner, for pink oyster mushrooms, the concentration of 1-octen-3-ol during freeze-drying in caps and stipes was 31.05 g/g d.w. and 176.17 g/g d.w., respectively, whereas during hot air-drying, it significantly decreased to 1.59~9.66 g/g d.w. and 1.96~15.77 g/g d.w. Furthermore, most volatile compounds showed a tendency to decrease in concentration as the temperature during hot air-drying increased.
        4,000원
        59.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The aim of this study is to investigate the enhancement of performance and the mix design method for asphalt mixtures utilizing ferronickel slag, an industrial by-product METHODS : To enhance the performance of FNS asphalt, waste tire powder (CR) was incorporated, and the characteristics of FNS asphalt aggregate, along with the impact of CR, were evaluated through the mix design process. RESULTS : CR is found to be suitable with a size of 30 mesh, and the optimal usage amount is determined to be 1±0.1% of the mixture weight, considering dense grade asphalt mixture. Volumetric design considering the swelling characteristics of CR is necessary, and a mixing design with a consistent tendency can be achieved only when an appropriate VMA is secured. CONCLUSIONS : The mix design for FNS-R asphalt mixture requires an increase of approximately 1% in VMA compared to conventional dense-graded asphalt mixtures to accommodate the swelling of CR. Additionally, FNS-R asphalt exhibits improved resistance to rutting comparable to modified asphalt and meets quality standards, including stripping resistance.
        4,000원
        60.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Derive a road pavement design method using Geocells, aim to derive a road pavement design and construction method suitable for the characteristics of the Bangladesh region METHODS : To assess long-term performance during road construction in Southeast Asia using Geocells, field tests and numerical analysis are conducted to verify stability. RESULTS : A total of 12 displacement measurements were conducted during the field tests, confirming an average load of 15.75 kN and an average displacement of 0.542mm. Inverse analysis was performed to obtain the properties of Geocell combined with compacted soil. The numerical analysis results confirmed that the insertion of Geocell provides better stability compared to the case with only compacted soil. CONCLUSIONS : Based on field tests and numerical analysis, a road design plan suitable for the Southeast Asian environment was proposed. A preliminary test section was selected in the Comilla region of Bangladesh, and test construction has been completed. Subsequent evaluations of the structural performance by soil layer in the test construction area will be conducted to develop a Geocell road pavement method, taking into consideration the characteristics of the Bangladesh region.
        4,000원
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