• Journal of The Korean Association For Science Education
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• v.20 no.4
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• pp.510-518
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• 2000

The purpose of this study was to develop learning materials for the discussion and examine the effects of the discussion learning over the students' conceptual change on force and motion. The subjects consisted of 360 middle school students, comprising of 5 discussion groups of 185 students and 5 traditional learning groups of 175 students. The results indicated that students in the discussion groups showed higher achievement than those in the traditional learning groups. Therefore this study supported the importance of discussion in conceptual change. However further research should be conducted to examine other educational effects of discussion.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.63-68
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• 1999

The purpose of this study is to design the framework of DSS (Decision Support System) for drought mitigation with internet and web interface. The users who apart from central government always connect to its main server via iternet. And web interface and browser operable models make it possible to analze data related with drought and planning for drought mitigation . Thereby, it need to build a database system , which manages data update from the users, and develop java-applet programs to assist decision making. The framework of DSS might be nicely adapted to the planning and decision making for the agricultural drought migigation.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.20-23
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• 2007

활선작업시 개폐섬락전압은 철탑형태와 작업유형에 따라 개폐섬락전압이 달리 나타나게 된다. 즉, 활선작업자의 위치, 철탑 종류 및 애자장치 종류 등에 따라 개폐섬락전압은 다르게 나타나기 때문에, 적용하고자 하는 활선공법이 있다면, 이에 대한 개폐섬락전압의 특성을 파악해 둘 필요가 있다. 점퍼V련은 일반적으로 선로의 수평각이 중각도 지역에 설치된다. 즉, 수평각이 너무 커서 조립식 점퍼장치를 설치할 수 없는 철탑에 점퍼V련 장치를 설치한다. 765kV 송전선로에서 실제 점퍼V련 장치가 많이 설치되어 있지 않으나, 이 경우에도 유지보수 사항이 발생할 수 있기 때문에 안전한 활선작업을 위한 실규모급 개폐섬락특성에 대해 검토할 필요가 있다.

• Proceedings of the KIEE Conference
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• 2007.04b
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• pp.28-30
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• 2007

본 논문은 변압기의 과부하 상태를 모의하고 내부 절연물의 잔존수명을 평가하기 위한 방법으로 열적 스트레스를 인가한 가속 수명 시험을 수행하여 광유 함침 절연지의 전기적 기계적 열화 특성을 분석하였다. 시험에 사용된 절연 재료는 변압기의 주 절연물로 널리 사용하고 있는 셀룰로스계 크래프트 절연지와 광유계 절연유를 사용하였다. 가속 열열화 시험은 IEEE/ANSI Standard C59.91-1981의 수명 예측 곡선에 의거하여 국내 배전환경에 부합하도록 $55^{\circ}C$ 절연시스템을 기준으로 하였으며, $150^{\circ}C$에서 약 1,000시간 동안 열 스트레스를 인가함으로써 변압기의 수명이 다하도록 모의하였다.

• Journal of ILASS-Korea
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• v.26 no.4
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• pp.182-188
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• 2021

In this paper, using a transfer function-based analytical model, major factors influencing the acoustics and combustion instability in a two-stage duct system composed of a nozzle and a combustor were derived and their quantitative effects were evaluated. From the acoustic analysis, it was confirmed that the change in reflection coefficient and mean flow could have a great influence on the instability growth rate, and the area ratio and speed of sound ratio between the nozzle and the combustor are also key parameters to determine combustion instability as well as flame transfer functions.

• Journal of Applied Biological Chemistry
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• v.57 no.4
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• pp.337-340
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• 2014

In the present study, water extracts of Acanthopanax divaricatus var, albeofructus and Eleutherococcus divaricatus var. chiisanensis were prepared and their antioxidant and anti-inflammatory effects were compared. The water extract of Acanthopanax divaricatus var, albeofructus showed significantly higher activity in total polyphenol and flavonoid contents, while there were no significant differences in ABTS/DPPH radical scavenging activities and ferric reducing antioxidant power. However, the water extract of Eleutherococcus divaricatus var. chiisanensis at the highest dose showed significantly lower capacity in nitric oxide production than that of Acanthopanax divaricatus var, albeofructus. Taken together, there were differences between Acanthopanax divaricatus var, albeofructus and Eleutherococcus divaricatus var. chiisanensis in total polyphenol/flavonoid contents and anti-inflammatory effect, however, the antioxidant effect was almost similar.

• Journal of Life Science
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• v.24 no.3
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• pp.219-226
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• 2014

The immune system protects the body from bacterial infection and disease, as well as cancer that develops following the mutation of cells. Aging exerts adverse effects on the immune system, such as chronic inflammation, resulting in rheumatoid arthritis. The purpose of this study was to investigate the anti-inflammatory effectiveness of Scutellaria baicalensis, which contains baicalin. HPLC analysis showed that S. baicalensis hot water extracts (SBWE) contained 42.2 mg/g of baicalin. To evaluate the cytotoxicity of SBWE, an MTT assay was carried out in Raw264.7 cells. No cytotoxicity was observed below 160 ${\mu}g/ml$ of SBWE. SBWE at 40 ${\mu}g/ml$ reduced the amount of nitric oxide produced by macrophages stimulated with lipopolysaccharide by 40%. In addition, SBWE inhibited phagocytosis stimulated with zymosan. Furthermore, the content of tumor necrosis factor-alpha ($TNF-{\alpha}$) produced by the macrophages was decreased in the presence of SBWE in a dose-dependent manner. SBWE also inhibited the production of interleukin-1 beta ($IL-1{\beta}$) in a time course experiment. Moreover, treatment with 20 ${\mu}g/ml$ of SBWE remarkably decreased the expression level of cyclooxynase-2. The results provide evidence that SBWE may exert an anti-inflammatory effect through modulation of the immune system.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.355-361
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• 2003

Immunostimulating effects of lactic acid bacteria as biological response modifier is a subject of growing interest, but the knowledge of these focused on some bacteria as Lactobacillus and Bifidobacterium. In this study, we investigated the effects of Pediococcus pentosaceus EROM101 on the immunostimulating and anti-cancer activity in murine model. P. pentosaceus was mainly found in Kimchi and fermented sea food and is facultatively anaerobic, catalase-netative, gram-positive cocci arranged in pairs, tetrads and clusters. The immunostimulating effects of P. pentosaceus EROM101 were evaluated using IgA production assay of Peyer's patch and proliferation assay of exudated immune cells of Balb/C mice fed P. pentosaceus EROM101 for 3 weeks. The macrophage and splenocyte proliferation were enhanced by orally administrated of P. pentosaceus EROM101. Also, IgA production in Peyer's patch increased by P. pentosaceus EROM101. Anti-cancer activity of P. pentosaceus EROM101 was appeared in Sarcoma 180 tumor-bearing ICR mice. However, this bacterium lysate itself appeared to have noncytotoxic substance against Sarcoma 180 cell in vitro. These results suggested that P. pentosaceus EROM101 reinforce immune system and therefore was revealed to be anti-cancer activity in mice.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.7-12
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• 2003

The purpose of this work is to investigate the effect of premixing condition on the combustion and exhaust emission characteristics in a HCCI diesel engine. To form homogeneous charge before intake manifold, the premixed fuel is injected into premixed tank by GDI injection system and the premixed fuel is ignited by direct injected diesel fuel. But in the case of high intake air temperature, premixed fuel is auto-ignited before diesel combustion and soot emission is increased. In the case of light load condition, the BSFC is improved by intake air heating because increased air temperature promoted the combustion of premixed mixture. NOx and smoke concentration of exhaust emissions are reduced compared to conventional diesel engine. The combustion characteristics of the HCCI diesel engine such as combustion pressure, rate of heat release, and exhaust emission characteristics are discussed.

• Korean Journal of Bronchoesophagology
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• v.2 no.1
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• pp.63-70
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• 1996

Reconstruction for hypopharynx and cervical esophagus after wide resection of extensive hypopharynx and larynx cancers have been used various methods including myocutaneous flaps, gastric pull up, md jejunal or large bowel free graft. Recently, the authors had experienced hypopharynx and larynx cancers with extension to the posterior hypopharyngeal wall and thoracic esophagus. Of course, these reconstructive methods should be selected in accordance with the patient's age, physical status, extend of prim.:W lesion, and defect after on block resection, however, gastric pull up was performed in hypopharynx cancer which had skipped lesion in the thoracic esophagus and jejunal free grafts were performed in case 2, 3 which had a extended lesions to the posterior pharyngeal wall. Some complications were noted, which were successfully stabilized by conservative managements. The gastric pull up and jejunal free graft were considered suitable methods for reconstrunction of hypopharynx and cervical esophagus, however, further studies are necessary about it.