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        검색결과 1,028

        101.
        2020.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Jeju Haenyeo have been playing a crucial role in Jeju economy for a long time. However, the number of Jeju Haenye has decreased since the 1970s, despite the efforts from the government and Jeju Provincial Office including a variety of welfare and benefits. In order to understand the unique culture of Jeju Haenyeo, and to provide a good program to help transfer their muljil skills, a qualitative research including in-depth interviews and participant observation in combination of an ethnographic method was performed. For the qualitative research, the interview preparation was reviewed, the language and culture of local communities were understood, and the location of the researcher was determined. Then, the following procedures were carried out; selecting informants, gaining their confidence, forming a rapport with them, and collecting data. For a preliminary survey, The first author visited Jeju alone for 10 days from late June to early July in 2015. The first author walked around the area and observed the dialects and life of local people from the viewpoint of an outsider. For interviews, four still active and three former Jeju Haenyeo were selected from skilled workers with diving experience of at least 20 to 60 years. The transfer of Jeju Haenyeo’s muljil skills, and their education and training vary, depending on the community culture of each village. As a result, the transfer of Jeju Haenyeo’s muljil skills is carried out not just at the level of maternal succession, but it is also performed by the village community that participate in co-childcare and joint training of diving skills.
        6,600원
        102.
        2020.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nanoporous silica aerogel insulation material is both lightweight and efficient; it has important value in the fields of aerospace, petrochemicals, electric metallurgy, shipbuilding, precision instruments, and so on. A theoretical calculation model and experimental measurement of equivalent thermal conductivity for nanoporous silica aerogel insulation material are introduced in this paper. The heat transfer characteristics and thermal insulation principle of aerogel nano are analyzed. The methods of SiO2 aerogel production are compared. The pressure range of SiO2 aerogel is 1Pa-atmospheric pressure; the temperature range is room temperature-900K. The pore diameter range of particle SiO2 aerogel is about 5 to 100 nm, and the average pore diameter range of about 20 ~ 40 nm. These results show that experimental measurements are in good agreement with theoretical calculation values. For nanoporous silica aerogel insulation material, the heat transfer calculation method suitable for nanotechnology can precisely calculate the equivalent thermal conductivity of aerogel nano insulation materials. The network structure is the reason why the thermal conductivity of the aerogel is very low. Heat transfer of materials is mainly realized by convection, radiation, and heat transfer. Therefore, the thermal conductivity of the heat transfer path in aerogel can be reduced by nanotechnology.
        4,000원
        103.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, the use of transfer slab system has increased greatly. However, several construction problems are being encountered owing to its excessive thickness. Therefore, in this study, a transfer slab system that uses a reverse drop panel, which can utilize the facility space of the pit floor by reducing the transfer slab thickness, was considered. To investigate the shear behavior of transfer slab system that uses the reverse drop panel, the two-way shear strength of transfer slab-column connection with the reverse drop panel was analyzed using nonlinear FE analysis. In addition, the two-way shear strength evaluations of transfer slab with the reverse drop panel conducted using the existing evaluation methods were verified by comparing the strengths predicted by those methods with the results of nonlinear FE analysis.
        4,000원
        104.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The establishment of porcine embryonic stem cells (ESCs) from porcine somatic cell nuclear transfer (SCNT) blastocysts is influenced by in vitro culture day of porcine reconstructed embryo and feeder cell type. Therefore, the objective of the present study was to determine the optimal in vitro culture period for reconstructed porcine SCNT embryos and mouse embryonic fibroblast (MEF) feeder cell type for enhancing colony formation efficiency from the inner cell mass (ICM) of porcine SCNT blastocysts and their outgrowth. As the results, porcine SCNT blastocysts produced through in vitro culture of the reconstructed embryos for 8 days showed significantly increased efficiency in the formation of colonies, compared to those for 7 days. Moreover, MEF feeder cells derived from outbred ICR mice showed numerically the highest efficiency of colony formation in blastocysts produced through in vitro culture of porcine SCNT embryos for 8 days and porcine ESCs with typical ESC morphology were maintained more successfully over Passage 2 on outbred ICR mice-derived MEF feeder cells than on MEF feeder cells derived from inbred C57BL/6 and hybrid B6CBAF1 mice. Overall, the harmonization of porcine SCNT blastocysts produced through in vitro culture of the reconstructed embryos for 8 days and MEF feeder cells derived from outbred ICR mice will greatly contribute to the successful establishment of ESCs derived from porcine SCNT blastocysts.
        4,000원
        105.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Somatic cell nuclear transfer derived embryonic stem cells (NT-ESCs) have significant advantages in various fields such as genetics, embryology, stem cell science, and regenerative medicine. However, the poor establishment of NT-ESCs hinders various research. Here, we applied fasudil, a Rho-associated kinase (ROCK) inhibitor, to develop somatic cell nuclear transfer (SCNT) embryos and establish NT-ESCs. In the study, MII oocytes were isolated from female B6D2F1 mice and performed SCNT with mouse embryonic fibroblasts (MEFs). The reconstructed NT-oocytes were activated artificially, and cultured to blastocysts in KSOM supplemented with 10 μM fasudil. Further, the blastocysts were seeded on inactivated MEFs in embryonic stem cell medium supplemented with 10 μM fasudil. A total of 26% of embryos formed into blastocysts in the fasudil treated group, while this ratio was 44% in the fasudil free control group. On the other hand, 30% of blastocysts were established NT-ESCs after exposure of fasudil, which was significantly higher than the control group (10%). The results suggest that fasudil reduced blastocyst development after SCNT due to inhibition of 2 cell cleavage while improved the establishment of NT-ESCs through the anti-apoptotic pathway.
        4,000원
        106.
        2020.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Graphene has attracted the interest of many researchers due to various its advantages such as high mobility, high transparency, and strong mechanical strength. However, large-area graphene is grown at high temperatures of about 1,000 °C and must be transferred to various substrates for various applications. As a result, transferred graphene shows many defects such as wrinkles/ripples and cracks that happen during the transfer process. In this study, we address transfer-free, large-scale, and high-quality monolayer graphene. Monolayer graphene was grown at low temperatures on Ti (10nm)-buffered Si (001) and PET substrates via plasma-assisted thermal chemical vapor deposition (PATCVD). The graphene area is small at low mTorr range of operating pressure, while 4 × 4 cm2 scale graphene is grown at high working pressures from 1.5 to 1.8 Torr. Four-inch wafer scale graphene growth is achieved at growth conditions of 1.8 Torr working pressure and 150 °C growth temperature. The monolayer graphene that is grown directly on the Ti-buffer layer reveals a transparency of 97.4 % at a wavelength of 550 nm, a carrier mobility of about 7,000 cm2/V×s, and a sheet resistance of 98 W/□. Transfer-free, large-scale, high-quality monolayer graphene can be applied to flexible and stretchable electronic devices.
        4,000원
        107.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to analyze the temperature and heat resistance distribution, which is a criterion for evaluating the cooling performance, by using computer simulation of the cooling system combined with the CPU of the individual highest heat generation section, and use it as important data for the heat sink design. Using a single material of Al 6063-T5, which is an integral part of the desktop, fan and heat sink, fins and base, the analysis was carried out with various fin numbers, thicknesses, pitches and shapes of heat sinks. Ambient temperature, 25°C, heat source, 130W and cooling fan speed, 2500 rpm (50CFM) were used as boundary conditions, and heat transfer characteristics regarding temperature distribution and heat resistance were investigated using ANSYS Icepak. As a result, it has been found that as the number of fins of heat sink increases, the heat dissipation area increases to decrease heat resistance, and as the distance between each fin decreases, the ventilation resistance increases to decrease the flow intensity of the cooling air in contact with the heat dissipation area. The sunburst array also exhibits better heat transfer characteristics by obtaining a lower distribution of heat resistance with a cooling effect of about 10°C than the one-way basic array.
        4,000원
        108.
        2020.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        MoO3 metal oxide nanostructure was formed by hydrothermal synthesis, and a perovskite solar cell with an MoO3 hole transfer layer was fabricated and evaluated. The characteristics of the MoO3 thin film were analyzed according to the change of hydrothermal synthesis temperature in the range of 100 ℃ to 200 ℃ and mass ratio of AMT : nitric acid of 1 : 3 ~ 15 wt%. The influence on the photoelectric conversion efficiency of the solar cell was evaluated. Nanorod-shaped MoO3 thin films were formed in the temperature range of 150 ℃ to 200 ℃, and the chemical bonding and crystal structure of the thin films were analyzed. As the amount of nitric acid added increased, the thickness of the thin film decreased. As the thickness of the hole transfer layer decreased, the photoelectric conversion efficiency of the perovskite solar cell improved. The maximum photoelectric conversion efficiency of the perovskite solar cell having an MoO3 thin film was 4.69 % when the conditions of hydrothermal synthesis were 150 ℃ and mass ratio of AMT : nitric acid of 1 : 12 wt%.
        4,000원
        109.
        2020.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        대류열전달은 겨울철 온실 열손실의 중요한 원인이 되며, 일반적으로 복사열에 의한 손실보다 더 크다. 스크린의 대류열전달계수를 자연상태에서 측정한 연구가 수행된 바는 있지만 상하면의 재질이 동일하고 공극이 없는 스크린에 대해서는 적용을 할 수 없는 방법이다. 이러한 재질의 스크린은 한국에서 많이 사용되고 있으나 대류열전달 특성을 파악하는데 많은 어려움이 있는 실정이다. 본 연구에서는 공극이 없는 3가지 종류의 스크린에 대해 대류열전달계수를 구하였으며, 계수를 산정하기 위하여 복사열수지 이론에 근거하여 산정방법을 개발하였다. 실험장치에 스크린을 설치하고 일사량, 장파복사량, 대기온도, 스크린 및 흑색천의 표면온도, 풍속 등을 측정하였다. 스크린의 표면온도와 주변온도의 차이에 따른 대류열전달계수를 산정하였다. 풍속이 거의 없는 상태에서 온도의 차이가 증가함에 따라 계수는 감소하는 것으로 나타났다.
        4,200원
        110.
        2019.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We apply a modified Convolutional Neural Network (CNN) model in conjunction with transfer learning to predict whether an active region (AR) would produce a ≥C-class or ≥M-class flare within the next 24 hours. We collect line-of-sight magnetogram samples of ARs provided by the SHARP from May 2010 to September 2018, which is a new data product from the HMI onboard the SDO. Based on these AR samples, we adopt the approach of shuffle-and-split cross-validation (CV) to build a database that includes 10 separate data sets. Each of the 10 data sets is segregated by NOAA AR number into a training and a testing data set. After training, validating, and testing our model, we compare the results with previous studies using predictive performance metrics, with a focus on the true skill statistic (TSS). The main results from this study are summarized as follows. First, to the best of our knowledge, this is the first time that the CNN model with transfer learning is used in solar physics to make binary class predictions for both ≥C-class and ≥M-class flares, without manually engineered features extracted from the observational data. Second, our model achieves relatively high scores of TSS = 0.640±0.075 and TSS = 0.526±0.052 for ≥M-class prediction and ≥C-class prediction, respectively, which is comparable to that of previous models. Third, our model also obtains quite good scores in five other metrics for both ≥C-class and ≥M-class flare prediction. Our results demonstrate that our modified CNN model with transfer learning is an effective method for flare forecasting with reasonable prediction performance.
        4,000원
        111.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        환경풍동 내 공기의 온도와 속도 변화에 대한 공기 유동과 전열 특성을 분석하기 위하여 수치해석을 수행하였다. 풍동 시험부 내 각 단면의 평균 속도, 균일도, 그리고 대류 열전달계수는 노즐 출구의 온도와 속도에 따라 큰 영향을 받게 된다. 노즐 출구로부 터 멀어질수록 평균 속도와 균일도가 점차 감소하고, 노즐 출구의 속도가 50km/h일 때 공기온도가 -40~60oC까지 변화함에 따라 단면 평균 속도와 균일도가 각각 약 12.9%와 13.5% 정도까지 증가하였다. 또한 시험부 바닥의 대류 열전달계수는 50~150km/h의 속도 변화에 대해 약 59.7%까지 증가하였으며, 공기의 온도와 속도가 증가함에 따라 시험부 열 유속도 함께 증가하였다. 본 연구에서 수행한 결과들은 최적의 환경풍동 설계에 필요한 주요 설계 자료로 활용될 수 있을 것으로 기대된다.
        4,000원
        115.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the structural stability of an align unit was studied to investigate the deformation and vibration characteristics of the upper and lower modules of the align unit during LCD panel transfer. The align unit consists of upper module and lower module. SolidWorks Simulation was used to analyze the structure, fatigue, and modes, to understand the deformation and vibration of the stiffness of the align unit. Because of the upper eccentric structure of the align unit, the main strain was large at the contact of the upper and lower modules and at the bottom of the support, and more pronounced at it’s front. The stress was large in the front support of the upper and lower modules, and the displacement was observed in the front of the upper module. The minimum life cycle that indicates the structural integrity of the align unit has exceeded its usable number. Also, the increase in natural frequency of the align unit gradually slowed down, as the vibration mode increased.
        4,000원
        116.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Heat transfer and pressure drop of horizontal heat exchangers with different configurations and installations numerically characterized. Three different heat exchangers were used and shaped as linear, wavy, and horizontal slinky, respectively. Installation depth was set from 0.5m to 3.0m and pipe spacing was ranged from 0.3m to 2.1m. The results showed that heat transfer rate and pressure drop were increased with the increase in the installation depth and the pipe spacing. The horizontal slinky heat exchanger carried more heat compared to others due to the greater effective heat transfer surface area per installation area. In terms of a ratio of heat transfer rate to pressure drop indicating the system efficiency, the linear heat exchanger performed better than others. On the other hand, the horizontal slinky heat exchanger was the most effective with respect to a ratio of heat transfer rate to installation cost.
        4,000원
        117.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        교량에서의 화재는 최근까지도 빈번하게 발생되고 있으며, 특히 케이블교량에서 화재가 발생될 시 케이블에 높은 온도상승으로 인해 케이블에 손상 및 파단이 발생될 수 있다. 본 연구에서는 케이블교량에서 발생될 수 있는 화재 시나리오를 설정하였다. 또한 실물차량 화재실험 결과를 토대로 화재강도모델을 제안하여 대상교량 케이블의 열전달 해석을 수행하였다. 해석 결과 단면적이 작은 케이블에서 더 높은 온도상승이 발생되며, 유조차를 제외한 차종의 경우 내화 성능 기준을 초과하지 않는 결과를 나타내었다. 유조차 화재의 경우 갓길에서 발생될 때 최소 단면적 케이블에서 내화 성능 기준을 초과하는 결과 를 보이며, 기준을 초과하는 케이블의 높이는 약 14m로 나타나 이에 따른 대책 및 내화 보강의 필요성을 확인하였다. 본 연구결과를 통해 케이블교량에서 화재가 발생될 때 케이블의 온도변화에 대한 간접적인 평가가 가능한 것을 확인하였으며, 향후 화재 발생 시 바람에 영향을 고려한 열전달 해석과 케이블의 온도상승 시 교량의 사용성에 대한 추가적인 연구가 필요할 것으로 판단된다.
        4,000원
        118.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        오늘날 양돈의 사양이 증가 함에 따라 부존사료 자원으로서 활용가치가 높은 물질에 항생제를 첨가 하지 않고 친환경적으로 제조된 가축용 사료를 개발하여, 기능성 친환경 돈육 및 가공품을 생산하는 것이 중요하다. 이에 따라 본 연구에서는 항암, 항염, 항산화 등 다양한 생리활성 물질이 다량 함유되어 있는 복분자(Rubus occidentalis, RO) 부산물을 양돈사료의 원료로 확립하고자 버크셔 돼지를 대상으로 복분자 발효사료(Rubus occidentalis fermented fodder, ROFF)의 혈액 내 영양 운반인자와 항산화 효능을 연구하기 위해 수행하였다. 시험구는 일반사료(대조구)에 ROFF를 0.3% 첨가하였고, 발효사료의 효능을 확인 하기 위해 각 체중에 따른 버크셔 거세돈 및 암퇘지에게 43~73일간 급여하여 효능을 확인 하였다. ROFF의 복합적인 효능은 혈액 생화학, 철분 및 항산화 분석을 통해 확인하였다. 그 결과 ROFF의 섭취로 인해 거세 자돈 및 육성돈, 암컷 자돈, 육성돈, 및 110-150 kg 암컷 비육돈 에서 total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C) 모두 감소하거나 HDL-C이 증가하는 경향으로 보아 영양생리학적으로 개선되는 경향을 확인하였다. 암컷 비육돈에서는 생화학적 수치가 모두 증가하는 경향으로 보아 임신 가능성이 있는 비육기의 경우 이러한 수치 향상으로 자돈의 생산을 위한 원활한 영양 공급이 예상되며, 건강한 자돈의 생산에 도움이 될 것으로 판단된다. Transferrin (TFE) 함량은 거세돈에서는 변화가 크지 않았으며, 암컷 육성돈 및 110-150 kg 암컷 비육돈에서 ROFF 섭취로 인해 증가하는 경향이 나타남에 따라 ROFF가 철분 결핍으로 인한 부정적인 영향들을 최소화 할 수 있을 것이다. Glutathione peroxidase1 (GPx1)분석 결과 거세 비육 돈 및 110-150 kg 암컷 비육돈에서 ROFF의 섭취로 인해 GPx1 활성이 유의적이지는 않지만 크게 증 가한 것으로 보아 ROFF가 항산화능을 향상시키는 것으로 판단된다. 본 연구의 결과들을 종합할 때, ROFF의 급여가 전체적으로 시험 개체의 개선 효능에는 영향이 크지 않으나 RO의 함량을 고려 할 때 매우 긍정적인 원료사료 중 하나라 할 수 있으며, 특히 ROFF가 거세돈 보다는 암컷 버크셔의 영양 운 반 및 철분 함량 등에 긍정적인 영향을 줄 수 있을 것으로 판단된다.
        4,000원