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        검색결과 121

        21.
        2020.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Two different casting speeds of 60 and 80mm/min are adopted to determine the effect of casting speed on the microstructure and mechanical properties of Al-Mg-Si/Al hybrid material prepared by duo-casting. The obtained hybrid material has a uniform and straight macro-interface between the pure Al side and the Al-Mg-Si alloy side at both casting speeds. When the casting speed is increased to 80mm/min, the size of primary α phases in Al-Mg-Si alloy decreases, without change of shape. Although the Al-Mg-Si alloy produced at higher casting speed of 80mm/min shows much higher ultimate tensile strength (UTS) and 0.2 % proof stress and lower elongation, along with higher bending strength compared to the case of the 60mm/min in casting speed, the tensile properties and bending strength of the hybrid material, which are similar to those of pure Al, are the same regardless of the increase of casting speed. Despite the different casting speeds, deformation and fracturing in hybrid materials are observed only on the pure Al side. This indicates that the macro-interface is well-bonded, allowing it to endure tensile and bending deformation in all hybrid materials.
        4,000원
        22.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 예비 마스터가드너를 선발, 정보를 전달하고 활동을 촉진시켜 프로그램 진행을 위한 실질적인 관리를 담당 하는 코디네이터 양성을 위해 데이컴 분석을 통하여 마스터가드너 코디네이터의 전문성 기준과 직무모형을 제시하였다. 1, 2차 데이컴 위원회를 통해 임무, 작업, 작업 요소를 도출하고 작업에 필요한 지식, 기술, 태도를 확정하였다. 도출된 임무 및 작업 등을 바탕으로 마스터가드너 교육을 담당하고 있는 시군 농업기술센터 농촌지도사를 대상으로 직무 수행평가를 시행하였다. 마스터가드너 코디네이터 직무분석 결과, <A. 정원문화 이해>, <B. 정원기술 이해>, <C. 봉사활동 이해>, <D. 교육과정 개발>, <E. 교육과정 운영>, <F. 교육사후 관리>, <G. 전문성 개발> 등 7개의 임무를 도출하였다. 또한 <A. 정원 문화 이해>의 4개, <B. 정원 기술 이해>의 4개, <C. 봉사 활동 이해>의 6개, <D. 교육과정 개발>의 6개, <E. 교육과정 운영>의 8개, <F. 교육 사후 관리>의 6개, <G. 전문성 개발> 의 7개 작업까지 총 41개의 작업과 173개의 작업 요소를 도출 하였다. 이를 토대로 작업과 지식, 기술, 태도의 관계를 분석 하고 매트릭스로 제작하여 마스터가드너 코디네이터 직무 활동에 사용하도록 하였다. 본 연구의 의의는 마스터가드너 코디네이터의 역할과 활동 범위를 설정을 위한 직무모형을 제안함으로써 향후 마스터가드너 코디네이터 직무교육 표준화 기준을 수립하고 일자리 영역을 구축하는 등 후속 연구를 촉진 할 수 있는 토대될 수 있을 것이라 사료된다.
        4,000원
        23.
        2019.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study aimed to examine the effect of a mild elevation in serum cholesterol level in a porcine coronary overstretch restenosis model using a balloon angioplasty catheter or drug-eluting coronary stent. Pigs were divided into two groups and were fed a commercial normal diet (CND, n = 4) or a high-fat diet (HFD, n = 4) for 5 weeks. Coronary overstretch injury by balloon angioplasty or stent implantation was induced in the left anterior descending and left circumflex artery after 1 week of feeding. Histopathological analysis was performed at 4 weeks after coronary injury. During the experiment, the total cholesterol level in the HFD group increased by approximately 44.9% (from 65.9 ± 3.21 mg/dL at baseline to 95.5 ± 9.94 mg/dL at 5 weeks). The lumen area in the CND group was reduced in comparison with that in the HFD group after balloon angioplasty. After stent implantation, the injury score showed no significant difference. There were significant differences in the neointimal area (2.7 ± 0.33 mm2 in the CND group vs. 3.3 ± 0.34 mm2 in the HFD group, p<0.05), lumen area (2.6 ± 0.54 mm2 in the CND group vs. 2.0 ± 0.33 mm2 in the HFD group, p<0.05), and percent area stenosis (52.0 ± 7.96% in the CND group vs. 62.4 ± 5.15% in the HFD group, p<0.05). Body weight change was not different between the two groups. Increased serum cholesterol level activated vascular smooth muscle cell proliferation in the porcine coronary overstretch model.
        4,000원
        24.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 기능성 게임의 교육적인 활용에 대한 관심이 증가하면서, 게임의 교육적 효과성에 대한 많은 연구들이 이뤄지고 있다. 본 논문에서는 인지기능 향상을 위한 기능성 게임인 ‘바우바우 프렌즈’를 개발했다. 이 콘텐츠는 인지기능 중 집행기능(Executive function), 지속적 주의력 (Sustained attention), 분리적 주의력(Divided attention)을 다루고 있다. 본 연구에서 개발된 게임의 유용성을 증명하기 위해 EEG 실험을 수행했으며, 게임 전 뇌파와 게임 진행 중 뇌파를 측정하여 비교분석했다. 결과적으로 지속적 주의력 게임(Simon)과 분리적 주의력 게임(Cooking)이 인지기능 향상에 긍정적인 효과가 있는 것으로 나타났다. 보다 아동의 인지기능 향상이라는 명확한 검증을 위해서는 추후 아동을 대상으로 한 EEG 실험을 추가로 수행할 필요가 있다.
        4,200원
        26.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to analyze the effectiveness of different storage periods of lactic acid bacteria (LAB)-fermented low moisture fresh rice straw silage. The low moisture fresh rice straw sample was inculcated with LAB and stored for different storage periods such as 45, 90, and 365 days, respectively. The low moisture fresh rice straw (LMFRS) silage inoculated with LAB exhibited reduction in pH throughout the fermentation as compared with the control (P<0.05). The lactic acid content was increased at the late fermentation period (90 and 365 days, respectively) in LAB inoculated LMFRS silage as compared with the control (P<0.05). In contrast, the acetic acid and butyric acid concentrations were slightly reduced in the LAB inoculated LMFRS silage sample at 90 and 365 days fermentation, respectively. Meanwhile, the non-inoculated LMFRS silage showed higher amounts of acetic acid and butyric acid at an extended fermentation with low bacterial population as compared with the LAB inoculated LMFRS silage. However, lactic acid concentration was slightly high in the non-inoculated LMFRS silage at early 45 days fermentation. Additionally, the nutrient profile such as crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF), and total digestibility nutrients (TDN) were not significantly different in control and LAB inculcated samples during all fermentation. Though, the microbial population was greater in the LAB inoculated LMFRS silage as compared with the control. However, the massive population was noted in the LAB inoculated LMFRS silage during all fermentation. It indicates that the inoculated LAB is the main reason for increasing fermentation quality in the sample through pH reduction by organic acids production. Overall results suggest that the LAB inoculums are the effective strain that could be a suitable for LMFRS silage fermentation at prolonged days.
        4,000원
        27.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of lactic acid bacteria (LAB) mixtures on low moisture Italian ryegrass (IRG) silage fermentation was evaluated in field conditions. The experiment was categorized into two groups: Un-inoculated (Control) and Inoculated with LAB mixture for four storage periods (45, 90, 180, and 365 days, respectively). Silage inoculated with the LAB mixture had the lowest pH with highest lactic acid production than the control from beginning at 45-365 days at all moistures. Higher LAB counts were observed in inoculated silages than the control silages at whole experimental periods. It is a key reason for the rapid acidification and higher lactic acid production in silages during the storage periods. Overall results suggest that an adding of LAB mixture had positive effects on the increasing aerobic stability of silage and preserved its quality for an extended duration.
        4,000원
        28.
        2019.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        While the reverberation mapping technique is the best available method for measuring black hole mass in active galactic nuclei (AGNs) beyond the local volume, this method has been mainly applied to relatively low-to-moderate luminosity AGNs at low redshift. We present the strategy of the Seoul National University AGN Monitoring Project, which aims at measuring the time delay of the Hβ line emission with respect to AGN continuum, using a sample of relatively high luminosity AGNs out to redshift z ∼ 0.5. We present simulated cross correlation results based on a number of mock light curves, in order to optimally determine monitoring duration and cadence. We describe our campaign strategy based on the simulation results and the availability of observing facilities. We present the sample selection, and the properties of the selected 100 AGNs, including the optical luminosity, expected time lag, black hole mass, and Eddington ratio.
        4,200원
        30.
        2019.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Acute myocardial infarction (AMI) is considered the major cause of mortality in the world. Tremendous animal studies are performed to develop novel therapeutics, and this study aimed to induce porcine myocardial infarction model by using polyethylene terephthalate (PET). Coronary guidewire was placed in left anterior descending artery (LAD). The balloon angioplasty catheter was inserted at the back of the PET. The balloon catheter was carefully pushed forward, until the balloon marker was located in mid-LAD. Coronary angiography was performed pre- and post-occlusion at 28 days by C-arm. Histologic analysis of heart tissue was performed 28 days after inducing AMI. Thirty three pigs were anesthetized and underwent percutaneous coronary catheterization. All pigs were successfully embolized in mid-LAD by PET. Fifteen pigs died due to ventricular fibrillation during post-anesthetic recovery time, and overall experiment mortality was 45.5%. In 2,3,5- triphenyl tetrazolium chloride staining, gross finding of the ischemic heart lesion showed firm and white area of infarction associated with the apex and left ventricular posterior wall. Infarct on H&E-stained sections demonstrated a region without myocytes and rich with cardiomyocyte with atypical nuclei. Successful induction of AMI by using PET may provide the pathophysiological information of ischemic heart disease and improvement of therapy development for AMI.
        4,000원
        33.
        2019.04 구독 인증기관·개인회원 무료
        This study was carried out to confirm the predatory and developmental features of N. stenoferus. We determine the host range of N. stenoferus. As a result, it was confirmed that Aphis gssypii, Myzus persicae, Planococcus citri, and Frankliniella occidentalis. N. stenoferus is thought to be able to feed on other micro pests. The test for a developmental period of N. stenoferus at 25℃ showed that the egg period was about 10 days. The nymphal period was about 18 days. Each nymphal period from 1st instar to 3rd instar nymphs was about 3 days. And the nymphal period of 4th and 5th were about 3.5 and 6 days, respectively. The female adult laid eggs in stem tissue or on leaves, and sometimes on the soaked cotton for water supply.
        34.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        고온기 화색발현이 우수하고 연중생산이 가능한 수출용 스프레이국화 신품종을 육성하기 위하여 충남농업기술원 화훼 연구소에서 2010년 분홍색의 모본 ‘Borami’를 방임수분하였다. 2011년에 종자를 파종하였고, 이중 화형과 화색이 우수한 개체를 선발하여 ‘SP11-148-01’로 계통명을 부여하였다. 2011년부터 2013년까지 주년 생산성을 위해 전조, 자연, 차광재배로 특성을 각각 검정하였고, 생육 및 개화특성은 화형과 화색이 비슷한 자주색 스프레이국화인 ‘Kingfisher’를 대조품종으로 조사하였으며, 2013년 ‘Yes Ruby’로 품종등록 출원하였다. ‘Yes Ruby’는 자주색의 설상화와 연녹색의 통상화로 가을 작형 개화기는 10월 24일로, ‘Kingfisher’의 10월 29일에 비해 빨랐다. ‘Yes Ruby’의 초장과 줄기굵기는 각각 94.9cm와 7.7mm로 ‘Kingfisher’의 89.2cm와 6.4mm보다 컸다. ‘Yes Ruby’의 꽃 직경은 6.2cm로 ‘Kingfisher’의 5.0cm보다 컸으며, 꽃잎수도 ‘Yes Ruby’가 25.7개로 ‘Kingfisher’의 23.3개보다 많았다. 착화수는 두 품종 모두 비슷하였으며, 흰녹병 저항성은 ‘Yes Ruby’가 2단계, ‘Kingfisher’는 3단계의 감염 정도를 나타내어 흰녹병에 대한 저항성이 높은 것으로 나타났다. 재배상 유의사항은 ‘Yes Ruby’는 겨울철 균일한 개화가 이뤄지지 않아 겨울철 야간온도를 18℃ 이상으로 관리해줌으로써 균일개화를 유도할 수 있다. 또한 생장억제제인 Daminozide을 처리함으로써 설상화수를 늘려 볼륨감 높은 꽃봉오리를 형성할 수 있어 고온기에도 화색발현이 우수하고 연중생산이 가능하여 안정적 수출을 통한 농가소득 증대에 기여할 수 있을 것으로 기대된다.
        4,000원
        35.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Yesan-gun was selected to receive a “Village Community Garden Project” in 2018 to foster a sense of community and improve the urban landscape by working with neighbors to create a happy living space for residents. Yesan-gun selected Sapti Park, located in Yesan-eup, as the project site. The project was carried out through the design charrette method (an intense period of collaborative creativity) to allow residents to propose and design park concepts themselves for the community garden construction project to ensure that that the park facilities would provide something for everyone to enjoy. This study followed the actual design project that actively introduced the design charrette in planning the community garden, describing the entire design process from planning to construction and revealing how the opinions of residents were projected onto the design drawings. The purpose of the project was to advance user-participation design methods by reviewing the progress of the design charrette process and to examine how storytelling, the act of conveying ideas through a fun and persuasive story, transformed the plans for the community garden.
        4,300원
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