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        검색결과 2,106

        1.
        2024.03 구독 인증기관·개인회원 무료
        콘크리트 포장의 조기 파손을 초래하는 콘크리트 혼합물의 품질 저하는 최근 종종 발생되고 있다. 이로 인한 유지보수 비용 또한 증 가하는 추세이다. 본 연구는 이러한 문제를 해결하고자 콘크리트 배합 시 효과적으로 유변학적 특성을 측정하여 콘크리트 품질을 예 측할 수 있는 시제품 개발을 연구 중이다. 현재 상용화되어 사용되고 있는 ICAR Plus Rheometer 장비의 이론을 변경 적용하여, 본 시제품 Twin Shaft Rheometer mixer를 개발하였다. 동시에 레오미터 장비를 활용해 유변학적 특성을 확인하고 측정하였다. 콘크리트 의 변형과 움직임을 분석하기 위해 수직, 수평 거동의 비교분석을 진행하였고, 흐름 저항성과 토크 점성을 이용하여 유변학적 특성을 기존 장비와 비교 분석하였다. 그 결과 절댓값의 차이는 존재하나 선형적 유사성을 가지는 것을 알 수 있었다. 높은 정확성을 위해 추 가연구는 진행하고 있다. 추가로 슬럼프 측정 센서 또한 개발 진행 중이며, 이 장비는 마이크로파를 통해 매질의 변화를 측정하여 슬 럼프를 유추하는 센서로 더욱 정밀한 결과값을 위해 추가연구 진행하고 있다.
        2.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        신뢰성 있는 토양의 이산요소모델을 개발하기 위해서는 토양의 특성을 고려하여 매개변수를 교정해야 한다. 본 연구에서는 이산요소모델을 구성하는 각 매개변수가 토양 입자의 거동에 미치는 영향을 분석하였고, 분석된 결과를 이용하여 토양의 이산요소모델을 개발하였다. 민감도 분석의 대상이 되는 매개변수는 전단 계수, 마찰 계수, 표면 에너지 등으로 선정하였으며, 교정의 기준이 되는 토양의 특성은 가비중, 안식각, 점착력 및 내부마찰각으로 선정하였다. 또한, 토성이 서로 다른 해안가, 논 및 밭을 구성하는 토양을 대상으로 연구를 수행하여 다양한 토성에 대한 적용성을 확인하였다. 결과적으로 본 연구에서 수행한 민감도 분석 결과를 이용하여 각 토양의 거동을 모사할 수 있는 이산요소모델을 교정하였으며, 시험 결과와의 비교를 통해 교정된 이산요소모델을 검증하였다.
        4,500원
        3.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Occurrence of process environment changes, such as influent load variances and process condition changes, can reduce treatment efficiency, increasing effluent water quality. In order to prevent exceeding effluent standards, it is necessary to manage effluent water quality based on process operation data including influent and process condition before exceeding occur. Accordingly, the development of the effluent water quality prediction system and the application of technology to wastewater treatment processes are getting attention. Therefore, in this study, through the multi-channel measuring instruments in the bio-reactor and smart multi-item water quality sensors (location in bio-reactor influent/effluent) were installed in The Seonam water recycling center #2 treatment plant series 3, it was collected water quality data centering around COD, T-N. Using the collected data, the artificial intelligence-based effluent quality prediction model was developed, and relative errors were compared with effluent TMS measurement data. Through relative error comparison, the applicability of the artificial intelligence-based effluent water quality prediction model in wastewater treatment process was reviewed.
        4,800원
        4.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In alignment with South Korea's “3020 Renewable Energy Expansion Plan,” this study focuses on the developing large-scale floating wind turbines. It addresses the challenges of increased size and cost in floating structures for wind turbines over 10MW. This paper details the preliminary design of a novel floating substructure utilizing composite materials(ie, EVA). Structural analysis was performed using ABAQUS, accounting for both typical and extreme wind conditions. Results from the analysis validate that the substructure design is adequately feasible for implementation.
        4,000원
        5.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        벼밤나방[Sesamia inferens (Walker, 1856)](나비목: 밤나방과)은 벼 줄기를 가해하는 해충이다. 본 연구는 국내 몇 지역에서 벼밤나방의 연 중 세대수를 추정하였다. 북위 38° 부근의 세 지역에서 벼밤나방 성충이 성페로몬트랩에 포획되었다. 이는 국내 모든 지역에서 벼밤나방이 서식하 는 것을 나타냈다. 조사된 지역 대부분에서 단일사인곡선의 유효적산온일도 모델로 추정된 세대별 성충 발생 시기는 관찰된 성충 세대의 발생 시기 와 차이가 없었다. 이 모델을 사용하여 추정된 월동유충은 성충 마지막 세대로부터 유래할 가능성이 있다고 추정되었다. 중남부지역에서 가을동안 벼 포장에서 채집된 유충들을 25°C에서 사육하였을 때, 번데기의 약 70%가 용화전 유충 탈피를 보이지 않았다. 경남 고성에서 3월초에 채집된 유 충은 25°C 사육에서 유충 탈피 없이 용화하여 이 지역에서는 주로 마지막 유충 영기로 월동할 것으로 추정되었다. 모든 결과를 종합하여 벼밤나방 은 북위 38° 부근 지역에서는 주로 2세대, 북위 35.3° ~ 37.3° 사이 지역에서는 3세대가 경과할 것으로 결론지었다. 별도로, 시토크롬 c 산화효소 1 유전자의 염기서열을 분석한 결과, 성페로몬트랩에 포획된 종의 35%가 다른 종이었고, 이들은 형태적으로 벼밤나방과 혼동되지 않았다.
        5,100원
        6.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Owing to its diverse range of bioactive compounds, Ganoderma lucidumhas garnered significant research attention for health promotion and disease prevention. Ganodermanondiol, which has a triterpenoid structure, is one of the major active compounds of G. lucidum. In the present study, the anti-inflammatory effects of ganodermanondiol were investigated to evaluate its usefulness as a functional ingredient. Ganodermanondiol (0.5–2 g/mL) significantly inhibited the production of nitric oxide (NO), the expression of the cytokines tumor necrosis factor (TNF)??and interleukin 6 (IL-6), and the expression of cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) in lipopolysaccharide-induced RAW 264.7 (murine macrophage) cells. Ganodermanondiol (0.5–2 g/mL) also inhibited the phosphorylation of mitogen-activated protein kinase (MAPK) signal molecules, including p38 and c-Jun N-terminal protein kinase (JNK) in RAW 264.7 cells. Ganodermanondiol significantly inhibited the essential factors involved in the inflammatory responses of RAW 264.7 cells and would, therefore, serve as a potential prophylactic and therapeutic agent for immune-related diseases.
        4,000원
        8.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Purpose: This study aimed to explore the practical experience of nursing graduates through a clinical practicum alternative program during the COVID-19 pandemic. Methods: Participants in this study comprised sixteen students who had gone through clinical field practice and clinical alternative programs during 4 semesters at nursing college. Data were collected through individual in-depth interviews and analyzed via the phenomenological research method developed by Colaizzi. Results: From the meaningful statements offered by the participants, six theme clusters emerged: (a) interest in new experiences, (b) practice that doesn’t feel like practice, (c) limits on yourself, (d) ambivalence about alternative programs, (e) longing for vivid clinical settings, and (f) choice in an unavoidable situation. Conclusion: This study provides a profound understanding of the practical experiences of nursing students during the COVID-19 pandemic situation about the clinical practicum alternative program. Based on this study, it is necessary to determine how students who have participated in the implementation of the clinical practice alternative program are adapting to the actual field as nurses. It is also necessary to develop various programs that reflect the needs of students and utilize technologies such as virtual reality, augmented reality, and metaverse along with current teaching methods.
        4,500원
        15.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to analyze the variations in online clothing purchasing patterns based on demographic attributes and purchasing behavior. The survey subjects comprised individuals in their 10s to 50s who had prior experience with online shopping. The survey was conducted in Gyungnam from May to June 2022. A total of 397 questionnaires were analyzed using the χ2-test statistical method. The analysis of clothing purchase type based on demographic characteristics revealed differences in terms of gender, marital status, age, monthly income, and occupation. Notably, when analyzed by demographic characteristics and clothing purchase types, monthly online purchase frequency displayed significant differences in marital status, age, and occupation. Similarly, monthly purchase amounts through online platforms exhibited significant variations based on marital status, age, monthly income, and occupation. The online fashion platforms, when examined in relation to demographic characteristics and purchase types, showed significant differences across all variables. Clothing purchases by consumers seeking individuality and differentiation exhibited significant differences in age, occupation, and purchase types. Furthermore, the reasons for choosing online platforms for clothing purchases varied significantly based on age and occupation. These findings indicate diverse purchasing behaviors on online platforms influenced by demographic characteristics. These findings can be valuable for effectively segmenting the online fashion market.
        6,000원
        17.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aquarium pet trade is a source of potentially invasive crayfish species, which can be subsequently intentionally or unintentionally introduced into new environments. There were 34 species of freshwater crayfish imported into Korea for ornamental purposes. Starting with 1 species in 2008, it shows a trend of continuous increase every year with the maximum of 25 species in 2020. The number of freshwater crayfish imported into Korea for ornamental purposes was 1,172,159, with an annual average of 78,144 being imported. The population also recorded a record high in 2017 with a 38% increase in population imports compared to the previous year. Among the 34 pet crayfish imported into Korea, four species classified as high-risk and managed in the US and Europe were American crayfish (Procambarus clarkii), Cherax quadricarinatus, Cherax cainii, and Cherax destructor. In addition to American crayfish (P. clarkii), 3 types of high-risk invasive crayfish are designated as legally managed species by conducting an ecological risk assessment, raising awareness among importers, retailers and consumers through awareness-raising education on freshwater crayfish, and measures for route management such as species identification and improvement of labeling methods are needed.
        4,000원
        18.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study uses FMECA (Failure Modes, Effects, and Criticality Analysis) and HAZOP (Hazard and Operability), which are widely applied in industrial areas, among risk assessment methods, and applies them to the same system. While FMECA evaluates system failure conditions and analyzes risks, HAZOP evaluates the system comprehensively by evaluating operational risks that may occur based on system parameters. According to data released by the Ministry of Land, Infrastructure and Transport, as of December 2021, the length of roads in Korea is 113,405 km, and the repair of guardrails that have expired must be fixed urgently in terms of traffic safety. Replacing all of these guardrails with new ones requires a very large cost, but if the guardrails are repaired with a vehicle equipped with the G-Save method, carbon emissions are reduced, the repair period is shortened, and great economic benefits can be obtained. However, risk assessment for guardrail coating vehicles has not been done so far. Focusing on this point, this study aims to evaluate the risk of these coating vehicles and describe the results. Finally, we found that the Risk Priority Numbers(RPN) in the FMECA risk assessment were greatly reduced, and 6 risk factors from HAZOP risk assessment and actions were taken.
        4,000원
        19.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        호박꽃과실파리(Z. scutellata)는 박과작물에 피해를 주는 중요한 해충이다. 현재 큐루어(Cuelure)는 국내에서 검역 대상 해충으로 규정된 오이과실파리, 타우과실파리, 및 퀸슬랜드과실파리와 더불어 호박꽃과실파리 수컷 성충의 예찰에 다양한 제형으로 활용되고 있다. 본 연구는 액 체, 고체, 및 왁스제형의 큐루어에 대한 호박꽃과실파리 수컷 성충의 야외 유인효과를 검증하기 위한 것으로 2021년 4월부터 10월까지 제주 2개 지역과 경북 1개 조사에서 2주 간격으로 모니터링하였다. 호박꽃과실파리의 발생밀도가 높은 제주지역에서는 7월부터 8월에 액체와 왁스제형의 큐루어에 호박꽃과실파리가 더 많이 유인되어 통계적인 유의차가 있었으나, 호박꽃과실파리의 발생밀도가 낮은 경북지역에서는 제형별 유인력 에 차이가 없었다. 야외조사 결과를 바탕으로 액체와 왁스제형의 큐루어가 호박꽃과실파리 수컷 성충 예찰에 권장되며, 이 두 제형의 큐루어에 유 인되는 검역 대상 과실파리류의 국내 예찰에 효과적일 수 있다.
        4,000원
        20.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the average temperature on Earth increases due to global climate change, crops are further needed to overcome this issue. Since sweet potato has high yield potential, can grow in harsh environments, and contains abundant nutrients, it is a potential substitute food in response to environmental crises. Compared to grains such as rice and barley, sweet potato has a lower glycemic load and contains various natural antioxidants, showing a variety of physiological functions. Thus, sweet potato is in the spotlight as a healthy food. Although domestic sweet potato production continued to decrease from 1990 to 2010, its production was maintained or slightly increased until 2020 due to the changes in consumers’ dietary habits that emphasize health. In this regard, steamed or roasted sweet potatoes were consumed as a snack substitute in the previous eating form. Furthermore, sweet potato starch has been used in various industries, including food. Therefore, this study intends to discuss the value of sweet potatoes as food, the production trend and cultivation method of sweet potatoes in South Korea, and the industrial application of sweet potatoes.
        4,000원
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