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        검색결과 334

        1.
        2025.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        남극 로스해 보퍼트 섬 인근에서 획득한 코어퇴적물로부터 고환경변화를 복원하기위해 규조를 분석하였다. RS19-GC09코어로부터 총 27속 5 7종의 규조를 감정하였으며, 규조의 생산성을 나타내는 개체수 농도는 0.01-28.75×107/g 범위에 해당하였다. 규조의 수직분포 변화를 토대로 4개의 군집대를 설정하였다. 해빙종(Sea-ice species: TC); Fragilariopsis curta, Fragilariopsis linearis, Fragilariopsis obliquecostata, Fragilariopsis ritscheri와 Pseudo-nitzschia turgiduloides)와 공해종(Open water species: TW); Fragilariopsis kerguelensis, Thalassiosira lentiginosa, Thalassiosira antarctica와 Rhizosolenia styliformis)의 산출을 대자율(Magnetic Susceptibility; MS)과 총유기탄소(Total organic carbone; TOC)값과 비교하였다. 군집대 I은 낮은 TC, TW와 TOC를 보이고, 반대로 높은 MS 곡선을 나타내어 두꺼운 해빙 또는 빙붕 하부 환경에 해당하였다. 군집대 II는 높은 TC, 증가하는 TW와 TOC, 반대로 낮아지는 대자율을 나타내어 계절적인 해빙의 지속기간이 길고 분포가 확장되었다. 군집대 III은 감소된 TC, 높은 TW과 TOC, 가장 낮은 곡선의 MS를 보 이는 구간으로 공해환경의 지속기간이 길었던 시기이다. 군집대 IV에서는 TC의 증가와 반대로 TW가 감소 하며, TOC 값은 유의미한 변화를 보이지 않고, MS가 약간 상승하는 시기로서 다시 해빙의 지속기간이 길어 졌음을 나타낸다.
        4,000원
        3.
        2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated changes in volatile organic compounds (VOCs) and aerosol particle concentrations following the use of certain spray-type household chemical products in an indoor environment. Four commercially available products in South Korea (including sticker/tar removers, a razor cleaner, and a fabric stain remover) were analyzed using real-time VOC monitoring with proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) and particle number concentration measurement with an Optical Particle Sizer. Immediately after spraying 17 grams of each product, VOC concentrations increased sharply, and hazardous substances such as benzene, 1,3-butadiene, formaldehyde, and acrolein remained at elevated levels for a certain period. Additionally, some products exhibited benzene concentrations exceeding levels of potential exposure concern, and the operation of an air purifier reduced VOC levels by 73%. This research provides insight into changes in indoor air quality and associated exposure risks due to household chemical use, and it may serve as a basis for future air quality management and regulatory standards.
        4,800원
        4.
        2025.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the long-term dynamics of phytoplankton communities, key environmental factors, and indicator species in Mulgeum, a major downstream site of the Nakdong River, from 1993 to 2020. Monthly phytoplankton densities ranged from 189 to 52,757,982 cells mL-1, with diatoms dominating yearround (29.1~93.4%). Notably, cyanobacteria exhibited the highest growth rates, which could exacerbate algal blooms under long-term climate change. Using generalized additive models, five environmental factorsdissolved oxygen, transparency, total phosphorus, phosphate, and discharge-were found to significantly influence monthly variations in most taxa. Cyanobacteria were most sensitive to environmental changes, while chrysophytes showed minimal dependence on specific factors. Principal component analysis grouped environmental conditions into five clusters, with each cluster characterized by distinct conditions and indicator species. A total of 122 species were identified as indicators, with green algae contributing the most. Cluster 1, characterized by high transparency and low phosphorus, was dominated by Stephanodiscus hantzschii, a common species in eutrophic waters. Cluster 4, associated with high phosphorus, highlighted Cyclotella ocellata as a key indicator, emphasizing phosphorus as a crucial determinant for diatom structure. These findings underscore the critical role of hydrological and nutrient factors in shaping phytoplankton communities and provide insights into ecological responses to environmental changes in the Nakdong River system. The results can inform sustainable management strategies to mitigate eutrophication.
        4,000원
        5.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The world population is rapidly increasing; over the past 40 years, it has risen by 3.3 billion, reaching 7.8 billion people. Globally, Solanaceae plants contribute more than 6.5 million tons of food to the world’s diet, with potatoes being the fourth most produced crop, cultivated in over 300 countries. However, caution is necessary when consuming plants from the Solanaceae family, as they contain toxic substances known as alkaloids. While alkaloids can offer beneficial effects, such as antioxidants, anti-inflammatory compounds, and anti-cancer properties, tolerance to these compounds varies among individuals, meaning even very small amounts can have fatal effects.Among the major crops in the Solanaceae family, potatoes contain solanine and chaconine; tomatoes contain tomatine; and eggplants contain solasonine and solamargine. The concentration of these substances varies depending on the part of the plant, its developmental stage, and its variety. Additionally, levels can increase significantly due to environmental stress. The environment profoundly impacts the synthesis of secondary metabolites related to survival and defense. Research has confirmed that environmental conditions-such as high-temperature cultivation, low-temperature storage, drought and rainfall, strong light, weak light (shade conditions), and excessive fertilizer application-can increase alkaloid synthesis. Therefore, this study reviews research on alkaloids in Solanaceae crops.
        4,000원
        6.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 유아교사의 디지털 교수효능감과 디지털 놀이지원역량의 관 계에서 변화개방성과 전문성 지원환경의 매개효과를 분석하는데 목적이 있다. 이를 위해 D시와 S시의 유치원과 어린이집에 재직중인 유아교사 165명을 대상으로 자료를 분석하였다. 병렬다중매개모형을 분석하기 위 해 Hayes(2018)의 PROCESS Macro Model 4가 적용되었다. 분석 결 과, 유아교사의 디지털 교수효능감, 변화개방성, 전문성 지원환경, 디지 털 놀이지원역량은 통계적으로 유의한 정적 상관관계를 나타냈다. 또한 유아교사의 전문성 지원환경이 디지털 교수효능감과 디지털 놀이지원역 량 간의 관계에서 유의미한 매개효과를 나타냈다. 본 연구결과는 유아교 사의 디지털 놀이지원역량 향상을 위하여 디지털 교수효능감과 전문성 지원환경을 중요 변인으로 고려되어야 함을 시사한다. 본 연구결과는 유 아교사의 디지털 놀이지원역량 증진을 위한 실질적이고 유용한 기초자료 를 제공하는 데 의의가 있다.
        5,800원
        9.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study compared the climatic conditions and fruit quality of the ‘Shiranuhi’ mandarin. This variety is expanding to inland areas due to climate change and global warming. The main producing area of ‘Shiranuhi’ mandarin is Jeju Island. In the inland areas where ‘Shiranuhi’ mandarin is grown, the average temperature is 12.9-13.9℃, which is 3-4℃ lower than the temperature in Seogwipo (16.9℃) on Jeju Island. In these inland areas, there are frequent critical minimum temperatures (below –3℃) in January or February, making the open field temperatures unsuitable for growing ‘Shiranuhi’ mandarins. However, farmers in these areas have managed to mitigate this risk by maintaining an average temperature of 18.3℃ inside plastic houses, which are actively heated from December to March. The earliest full bloom of ‘Shiranuhi’ was recorded in Jindo, Jeollanam-do on April 10. The earliest harvest date was observed in Seogwipo, Jeju on January 9, which indicates the shortest maturity period of 272 days. The cumulative temperature inside the greenhouse was highest in Wanju, Jeollabuk-do at 5,755℃. Buan, Jeollabuk-do (5,517℃) and Seogwipo, Jeju (5,518℃) had nearly identical temperatures. Significant differences in fruit quality were observed between the inland areas and Jeju Island. These differences were observed in fruit length, summit length, firmness, and the CIE b* value of the peel. The climate differences seem to have a greater influence on the factors that determine the fruit shape among the fruit quality characteristics. The yield per tree was higher in Seogwipo, Jeju (38.3kg) compared to the inland areas (30 to 34kg). Inland areas predominantly featured medium to small fruits (251-300g), while Jeju Island had a higher proportion of larger fruits (over 350g).
        4,000원
        10.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        황해 식물플랑크톤의 계절별 군집 구조와 해양환경 요인과의 상관관계를 파악하기 위하여 2019년 계절별로 15개 정점에 대해 조사하였다. 동계와 춘계에는 규조류가 높은 출현율을 나타내었으며, 하계와 추계에는 20μm 이하의 미동정 미소편모조류가 높은 출현율 을 나타내었다. 이는 낮은 농도의 영양염류로 인한 것으로, 특히 인산염의 경우 검출 한계까지 낮게 나타남에 따라 식물플랑크톤 성장에 심각한 저해 현상을 가져온 것으로 판단된다. 성층이 강화되는 하계와 추계 표층 혼합층에서 초미소형 크기의 식물플랑크톤 기여도가 높 았으며, 중복분석 결과 초미소형 크기의 식물플랑크톤은 영양염(질산염, 인산염) 및 수심에 대해 강한 음의 상관성을 나타내고 있었다. 결 론적으로 하계와 추계 성층 강화로 인한 표층 혼합층 내에서의 영양염 감소는 영양염류의 요구량이 낮은 상대적으로 크기가 작은 식물플 랑크톤 성장에 유리한 환경을 제공하며, 식물플랑크톤 군집 구조는 소형화가 진행된 것으로 판단된다.
        4,200원
        13.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate immune changes by comparing the proportion and function of immune cells in the blood under high-temperature period and convalescence temperature period in Holstein dairy cows. The experiment was conducted using Holstein dairy cows of five animals per group (60 ± 20 months old, 175 ± 78 non-day) from the National Institute of Animal Science at high-temperature period (THI: 76 ± 1.2) and convalescence temperature period (THI: 66 ± 1.3). Complete blood count results showed no change in the number of immune cells between groups. In the analysis using Flow Cytometry of PBMCs, no significant differences were observed among B cells, Helper T cells, cytotoxic T cells, and γδ T cells between groups. However, there was an increase in Th17 cells producing IL-17a, while Th1 cells decreased during the convalescence temperature period. The results of gene expression analysis using qRT-PCR in PBMCs revealed an increase in IL-10 during the convalescence temperature period, while a decrease in HSP70 and HSP90 was observed. In conclusion, the increased expression of IL-10 and the decrease in HSP expression suggest the possibility of a weak recovery from heat stress. However, the lack of observed changes in B cells, T cells, and other immune cells indicates incomplete recovery from heat stress during the convalescence temperature period.
        4,000원
        17.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we examined dimensional changes in processing carbon fiber composites using a cost-competitive domestic high-speed router. Lacking temperature compensation features found in typical machines, it faces increased defect rates due to temperature fluctuations during processing. To mitigate this, we defined specific processing temperature conditions, established hole positions as distance references for various temperatures, and measured dimensional changes. This enabled us to calculate necessary dimensional corrections, minimizing thermal deformation.
        4,000원
        18.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the effect of crown heating on the cultivation environment, budding, flowering and yields of strawberry was analyzed. In December, January, and February, when the outside temperature was low, the average strawberry crown temperature at daytime in the test zone was 1.3°C higher than that in the control zone, and the average strawberry crown temperature at nighttime in the test zone was 2.7°C higher than that in the control zone. The average bed temperature at daytime in test zone was 1.7°C higher than that in the control zone, and the average bed temperature at nighttime in test zone was 2.4°C higher than that in the control zone. As a result of performing correlation analysis and regression analysis on strawberry crown temperature and budding period, the correlation coefficient was -0.86, which tended to be shorter as the crown temperature was higher, and the determination coefficient was 0.74. The total yields of strawberry during test period were 392.6 g/plant for test greenhouse and 346.0 g/plant for control greenhouse respectively. As for the quality of strawberries, the ratio of 2L (very large) grades and L (large) grades was 62.4% in the test greenhouse and 58.5% in the control greenhouse, indicating that the proportion of high quality strawberries was higher in the test greenhouse.
        4,000원
        19.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, a closed-type plant factory has been receiving attention as a advanced agricultural method. It has diverse advantages such as climate-independence, high productivity and stable year-round production. However, high energy cost caused by environmental control system is considered as a challenges of a closed-type plant factory. In order to reduce the energy cost, investigation about energy load which is directly connected to energy consumption needs to be conducted. In this study, energy load changes of a plant factory have been analytically analyzed according to the environmental changes. The target plant factory was a lettuce growing container farm. Firstly, the impact of photoperiod, set temperature and relative humidity change were examined. Under the climate condition of Daejeon in South Korea, increase of photoperiod and set temperature rose a yearly energy demand of a container farm. However, increase of set relative humidity decreased a yearly energy demand. Secondly, the climate environment effect was compared by investigating the energy demand under 9 different climate conditions. As a result, the difference between maximum and minimum value of the yearly energy demand showed 21.7%. Lastly, sensitivity analysis of each parameter (photoperiod, set temperature and relative humidity) has been suggested under 3 different climate conditions. The ratio of heating and cooling demand was varied depending on the climate, so the effect of each parameter became different.
        4,000원
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