• 한국해양학회지
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• 제20권3호
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• pp.30-36
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• 1985

洛東江 河口 一部 海域에서 觀察되는 黃綠色 水色帶의 發生原因과 性狀을 糾明하기 위하여 1984年 2月, 5月, 8月과 10月의 四次에 걸쳐 洛東江 河口의 10個 定點에서 水質調査를 實施하였다. 洛東江 河口 海域에 出現하는 黃綠色水色帶를 形成하는 것은 高 濃度의 浮遊物質로써, 그 中 平均 52%가 有機物에 該當하는 揮發性 浮遊物質로 構成되어 있다. 클로로필 a의 濃度는 黃綠色 水色帶 內部海域에서 平均 11.3mg/$m^3$이며, 最高 51.0mg/$m^3$으로써 周邊海域 및 他 海域에 比하여 매우 높은 濃度를 보이며, 溶存酸素는 過飽和 狀態이다. 營養鹽類 濃度도 黃綠色 水色帶 內部 海域이 外海側 海域보다 높고, 營養鹽類 濃度와 클로로필 a量과는 良好한 正의 直線的 相關關係를 나타낸다. 洛東江 河口 海域에 出現하는 黃綠色 水色帶는 洛東江에서 排出되는 土砂의 混濁뿐만 아니라 營養鹽類가 풍부한 洛東江 河川水의 影響으로 大量 繁殖한 植物性 플랑크톤의 發生으로 因한 것으로 보인다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.263-266
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• 2003

The fine $YBa_2Cu_3O_x$ powder ($0.2{\sim}1.0\;{\mu}m$) is produced by sol-gel method, and electrophoresis deposition is used for the preparation of $YBa_2Cu_3O_x$ thick films which are deposited on Ag wire. The oriented $YBa_2Cu_3O_x$ was tried to be prepared by the zone-melting method under low oxygen partial pressure. The orientation and the phase composition were examined by the X-ray diffraction and the superconductivities were measured by 4 line method. The critical current densities are still quite low, which may be due to unsuitable technical parameters for zone-melting of $YBa_2Cu_3O_x$ thick films. Therefore the heat treatment condition and controlling of low oxygen partial pressure should be improved in the future experiment.

• Restorative Dentistry and Endodontics
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• 제29권5호
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• pp.446-453
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• 2004

하악 대구치 근심치근의 danger zone에서 수종의 전동 니켈-티타늄 파일의 근관성형력을 근관성형 전후 치질 두께의 변화를 측정하여 평가하고자 하였다. 기구에 따라 총 40개의 하악 대구치를 10개씩 $Profile^{\circledR}$, GT Rotary file, Quantec 및 ProTaper 4개 군으로 나누고 각 치아당 2개의 근관을 straight up-and-down과 anticurvature 군으로 나누어 근단부 근관을 모두 30번 크기로 일정하게 확대하였다. 수정된 Bramante법을 사용하였으며 술전 및 술후의 근관 상아질 두께를 치수저 하방 1, 3 및 5 mm지점에서 측정, 이원변량분석법으로 통계분석하였다. 모든 군의 danger zone과 safe zone에서의 straight up-and-down 동작과 anticurvature 동작 사이에는 치근상아질 두께변화에 현저한 차이를 나타내지 않았다 (p > 0.05). ProTaper는 danger zone과 safe zone 모두에서 다른 기구에 비해 많은 량의 근관상아질 삭제를 보였으며 특히 분지부 3 mm 수준에서 현저하였다(p < 0.05).

• 한국산업보건학회지
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• 제21권4호
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• pp.185-192
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• 2011

To predict contaminant concentrations within a multi-zone work environment, an air quality model in the work environment was developed. To do this, airflow equations on the basis of orifice equation were solved by using the Conte and De Boor scheme, and then equations for the conservation of mass on contaminant were solved by using the fourth-order Runge-Kutta algorithm. To validate the accuracy of simulated results, this model was applied to the controlled environment chamber that had been tested in 1998 by Chung KC. The comparison of predicted concentrations by this study with measured concentrations by the Chung KC indicated that the average deviations were 2.66, 3.35, and 3.15% for zone 1, zone 2, and zone 3, respectively. Also, this model was applied to a working plant with four zones. Thus, the results of contaminant concentration versus time were predicted according to the schedule of the openings operation, and case studies were done for four cases of the openings operation to investigate the interaction of airflow and contaminant concentration. The results indicated that opening operation schedules had a significant effect on contaminant removal efficiency. Therefore, this model might be able to apply for the design of ventilation schedules to control contaminants optimally.

• 한국측량학회지
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• 제27권4호
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• pp.445-452
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• 2009

항공라이다를 이용한 도시지역 3차원 모델링에 대한 연구가 활발히 진행되고 있으며, 이를 위한 최적 점밀도 결정은 도시지 역 3차원 모델링의 성과 및 효율적인 항공라이다 활용을 위해 매우 중요 하다. 본 연구는 도시지역 항공라이다의 최적 점 밀도 결정을 위해 표본 점 밀도를 선정 하였다. 각 표본 점 밀도별 DSM 및 건물 외곽선을 이용해 최적 점 밀도 결정을 위한 시각적 평가 및 정확도 검사를 실시하였으며, 도시지역 항공라이다를 위한 최적 점 밀도를 제시 하였다.

• 한국토양비료학회지
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• 제48권3호
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• pp.153-162
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• 2015

Land information is important for the international agricultural companies. This study investigated the agriculture and soil information in Sri Lanka. This study is the results from investigation of soil properties and agricultural properties determined by the Soil Taxonomy classification system for the soils in Sri Lanka. The order of the main agricultural imports in Sri Lanka was wheat > refined Sugar > dry Onion > Rice > Lentils. The climate of Sri Lanka is divided into three climatic zones. There are a wet zone, an intermediate zone, and a dry zone. Rainfall of the wet zone was $3,000-5,000mm\;year^{-1}$. The rainfall of the dry zone was less than $1,000m^{-1}$. The intermediate zone was in the middle area. Soil series of Sri Lanka were 109 in total. Detailed information of soil series was: 6 of soil Orders, 15 of Suborders, 39 of Great groups, and 56 of Subgroups. Soil texture of topsoil was much more coarse, but subsoil was gravelly coarse soil. Soil of Sri Lanka was classified as a Soil Order. The orders were Entisols > Alfisols > Ultisols > Inceptisols > Histosols > Vertisols.

• 한국안전학회지
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• 제26권5호
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• pp.17-22
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• 2011

This study proposes feature extraction method of pattern recognition by evaluation of weld defects in weld zone of titanium. For this purpose, analysis objectives in this study are features of attractor quadrant and fractal dimension. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics resulting from distance shifts such as porosity of weld zone. These differences in characteristics of weld defects enables the evaluation of unique characteristics of defects in the weld zone. In quantitative fractal feature extraction, feature values of 0.87 and 1.00 in the case of part of 0.5 skip distance and 0.72 and 0.93 in the case of part of 1.0 skip distance were proposed on the basis of fractal dimensions. Attractor quadrant point, feature values of 1.322 and 1.172 in the case of ${\phi}1{\times}3mm$ porosity and 2.264 and 307 in the case of ${\phi}3{\times}3mm$ porosity were proposed on the basis of distribution value. The Proposed feature extraction of pattern recognition in this study can be used for safety evaluation of weld zone in titanium.

• 지질공학
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• 제24권3호
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• pp.323-332
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• 2014

The Nobi fault zone, which generated the 1891 Nobi Earthquake (M8.0), includes five or six faults distributed in and around Gifu and Aichi prefectures, Japan. Because large cities are located near the fault zone (e.g., Gifu and Nagoya), and because the zone will likely be reactivated in the future, relatively thorough surveys have been conducted on the 1891 Nobi earthquake event, examining the fault geometry, house collapse rate, and the magnitude and distribution of earthquake intensity and fault displacement. In this study, we calculated the earthquake slip along faults in the Nobi fault zone by applying a 3D numerical analysis. The analysis shows that a zone with slip displacements of up to 100 mm included all areas with house collapse rates of 100%. In addition, the maximum vertical displacement was approximately ${\pm}1700mm$, which is in agreement with the ${\pm}1400mm$ or greater vertical displacements obtained in previous studies. The analysis yielded a fault zone with slip displacements of > 30 mm that is coincident with areas in which house collapse rates were 60% of more. The analysis shows that the regional slip sense was coincident with areas of uplift and subsidence caused by the Nobi earthquake.

• 한국산업안전학회:학술대회논문집
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• 한국안전학회 1997년도 추계 학술논문발표회 논문집
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• pp.43-48
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• 1997

아트리움 공간에서 화재 발생시 연기 유동에 대하여 두 가지 형태의 화재 모델인 zone 모델과 field 모델을 이용하여 시뮬레이션 했다. 사용된 zone model은 NIST에서 개발된 CFAST(version 1.6) 모델이며 field 모델은 전산유체역학 이론을 바탕으로 자체 개발된 화재 모델이다. 본 연구는 정육면체 모양의 아트리움 공간에서 연기 유동과 온도 분포에 대하여 해석하고자 한다. 화재로 인해 야기된 유동에 대하여 속도장과 은도장을 예측하기 위한 계산 과정은 유한체적법 및 비엇갈림격자계를 이용하여 질량, 운동량, 에너지 및 성분 보존 방정식등에 대한 3차원 비정상상태 지배방정식을 사용했다. 수치해석 결과 zone 모델과 field 모델의 화재 모델에 의해 예측된 연기 층 평균 경계놀이와 상부 더운 연기 층의 평균 온도에 대하여 거의 유사한 결과를 얻었다.

• 한국레이저가공학회지
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• 제7권3호
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• pp.25-36
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• 2004

This study was performed to clarification of the formation of weld discontinuities in the dissimilar laser fusion zone. Welding parameters were beam power of 1300, 1430, 1560, and 1700 W and travel speed of 1, 1.3, and 1.7 m/min. Most cavities in the fusion zone were observed near the tip. Cavities in the fusion zone observed to be formed and grown from pores in the tip. More cavities were formed as the beam position moves to the tip side. Small cavities were decreased but large cavities were increased when the energy input increased. W content in the fusion zone was increased with heat input and as the beam position close to the tip. In the fusion zone, W content in the dendrite boundary was increased with heat input. Considering the propagation path and fracture morphology, cracks were solidification cracking, and were initiated and propagated along the dendrite boundaries. The formation of cracks might be related with the W rich ${\mu}$ phase which was formed in the grain boundaries and dendrite boundaries.