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呂運光 명지대학교 공학기술연구소 1988 공학기술연구소 논문집 Vol.3 No.-
The various types of turbulence models are presented. The necessity of the averaging procedure is stated in view of the spectral characteristics in turbulence structures. This paper includes the primary difference between the ensemble and the volume average methods, in which terms requiring closure are derived and analyzed. The basic concept of the eddy viscosity and diffusivity for the closure terms is reviewed, based upon the mixing length model, the one-equation model and the general two-equation model. The turbulent stress/flux equation model is also considered algebraically. Special attention is placed upon the introduction of the Yeo's averaging procedure totally different from the conventional approaches in turbulence modeling. This paper concludes with the discussion and the comparison of them above.
呂運寬,鄭光龍 홍익대학교 산업기술연구소 1998 産業技術 Vol.8 No.-
This study was examined on the effect of complexing agents for the throwing power, current efficiency and morphology of electrodeposited layer in the neutral zinc plating bath containing ZnCl_2(40g/l), KCI(100g/l), H_3Bo_3(60g/l), and complexing agent (90g/l) In terms of enlarging the bright range of plating EDTA(4Na salt) added bath was the best and sodium gluconate added bath was also good. However sodium gluconate added bath has a better result for the throwing power and current efficiency than EDTA added bath has. Throwing power is inclined to decrease slightly in both baths according to a rise in temperature and increase according to the current density and pH. In both bath, current efficiency decreases according to a rise current density and decreases slightly according to a rise in pH but increases according to a rise in temperature. Cross sectional micrograph of electrodeposited layer appeared not in the lamellar or columnar texture but in the very fine testure. The morphology of elecrodeposited surface was almost the same as obtained from Zine cyanide pl
임종철,이원민,김창성,여운광 명지대학교 산업기술연구소 2008 産業技術硏究所論文集 Vol.27 No.-
The recent heavy downpours, tsunami, and flooding in Korea have cause devastating casualties and astronomical economic losses. In addition, construction sites are exposed to the dangers of structural collapses and damages due to these natural disasters. Studies for monitoring the dangers of construction sites must focus on reducing the amount of casualties and improve prevention measures as their main purpose. The monitoring svstem developed in this study provides both vertical inclinometer and rainfall monitoring with credible accuracy. This system provides more efficient and safe construction site management and preventative measures possible.
EXPERIMENTAL STUDY ON THE CHARACTERISTICS OF RIVERBED MATERIALS USING AN ULTRASONIC SENSOR
Yeo, Woon-Kwang,Jang, Bok-Jin,Lee, Jong-Kook,Kim, Young-Bin Korea Water Resources Association 2006 Water engineering research Vol.7 No.1
The scouring process is complex and subject to many factors. Recently, experiments for real-time bridge scour monitoring have been active as means for a more reliable scour prediction. Riverbed materials are an important factor in bridge scouring; therefore, an accurate estimation of riverbed material is critical in predicting a scour. As a part of this approach, an ultrasonic sensor, which can not only detect river bottom during floods but can also be installed lose to the underwater structures, was developed. This sensor is able to map the river bottom using an ultrasonic waves with the characteristics of the returning wave, reflected from an object or bottom ground. The reflected wave is unique according to the situations, or materials below. Therefore, it would be possible to identify the consisting materials of a riverbed if we could reveal each characteristic in the received signals. In this study, a preliminary experiment was performed in the laboratory to identify and classify received signals, which is unique to each material. The analysis of this experiment gives the graph, which makes it possible to identify materials of the river bottom through the ultrasonic signals. The proposed graph was verified through a comparison with the actual field data measured in river.
DYNAMIC BEHAVIORS OF SEDIMENT TRANSPORT IN PALDANG RESERVOIR
Yeo, Woon Kwang 明知大學校 産業技術硏究所 1996 産業技術硏究所論文集 Vol.15 No.-
水深積分된 連續方程式 運動方程式을 사용하여 流動場과 濃度分布를 해석할 수 있는 動的移送模型을 구성하였다. 本 模型은 數値解析에 의하여 速度 및 水面變化를 산정하기 위한 흐름모형, 底面에서의 浮上 및 堆積을 나타내는 바닥모형, 濃度의 移動을 해석하는 移送模型등 3종류의 副模型 이루어졌으며 실제로 八堂湖에 적용시켜 湖水內 흐름양상과 濃度分布를 계산하였다. 計算結果를 實測値와 비교한 결과 청평댐에서의 尖頭發電으로 인한 湖水內 不定流현상을 잘 나타내고 있으며 경안천에서 流入되는 濃度의 擴散範圍를 豫測하는데 매우 유용함을 보이고 있다. A dynamic sediment transport model is numerically developed based on two-dimensional vertically averaged equations. The model consists of three submodels; a hydrodynamic model for velocity and free surface variations, a sediment bed model for erosion and deposition, and a transport model for sediment movement. Deposition/erosion process on the bed takes into account in a form of source/sink term for the transport equation. Being applied to Paldang reservoir, mechanisms of sediment transport practically controlling the deposition and resuspension are briefly investigated. It also provide better understanding on the physical transport of contaminant loadings by comparing loading estimates to bed materials collected in Paldang reservoir.
선박충돌방지공이 설치된 해상교량의 교각 세굴 특성 분석
여운광(Yeo, Woon-Kwang),지운(Ji, Un),김창성(Kim, Chang-Sung),임종철(Lim, Jong-Chul) 한국해안해양공학회 2008 한국해안해양공학회 논문집 Vol.20 No.2
최근 들어 선박의 항로에 위치하고 있는 대형 해상교량의 건설이 활발해짐에 따라 선박충돌의 위험성을 고려하여 교각 주변에 충돌방지공을 설치하는 경우가 많다. 이러한 충돌방지공 설치로 인해 교각의 세굴특성은 충돌방지공 설치 전의 교각 주변의 세굴양상과 매우 다르게 나타난다. 따라서 본 연구에서는 충돌방지공의 설치 유무에 따른 세굴의 형태를 분석하기 위해 인천대교를 대상으로 수리모형실험을 실시하였다. 충돌방지공 설치 전의 고정상, 이동상실험을 통해 유황과 세굴심 및 세굴공 범위를 파악하였으며 또한 충돌방지공 설치 후 실험을 통하여 최종적으로 충돌방지공으로 인한 교각 세굴 특성 변화를 분석하였다. 실험결과, 충돌방지공이 설치됨으로 인해 최대세굴심이 W1교각의 경우 약 0.24 m, W2+3+4교각의 경우 2.4 m 증가하는 것으로 나타났다. 또한 최대세굴심의 발생위치는 W1교각의 경우 충돌방지공 설치 전 후가 동일한 위치에서 발생하였으나 W2+3+4교각의 경우 설치 후 최대세굴심이 교각주변이 아닌 충돌방지공 주변에서 발생하였다. More recently, the massive marine bridges in a ship passage have been constructed on the sea. Therefore, the ship impact protection for the bridge-piers are installed to consider the possibility of vessel collision danger. Due to the ship impact protection, the pier-scour characteristics are changed in comparison with the condition without the ship impact protection (SIP). In this study, the physical modeling for the Incheon Sea-Crossing Bridge was performed to analyze the pier-scour characteristics with respect to the vessel collision protection. The rigid and movable bed tests were conducted to evaluate the flow pattern, scour depth, and scourhole with and without the ship impact protection. The experimental results for the maximum scour depth is increased 0.24 m in W1 pier at the same location and 2.4 m in W2+3+4 piers due to the SIP installation. Especially, the maximum scour depth in W2+3+4 piers was occurred around the SIP.