• Fisheries and Aquatic Sciences
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• 제13권3호
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• pp.236-243
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• 2010

Fecal sterols, nonylphenolic compounds (NPs), and polycyclic aromatic hydrocarbons (PAHs) were determined in surface water from Masan Bay and its adjacent rivers in February 2005. Concentrations of coporstanol (Cop), an indicator of fecal pollution, in surface water ranged from <10 to 13,853 ng/L, and concentrations of nonylphenol, the most toxic of the NPs, ranged from 10.2 to 481 ng/L, and concentrations of PAHs ranged from 8.61 to 223 ng/L. The concentrations of the compounds measured in this study were lower than or comparable to those at other locations in Korea and other countries. The contamination of Cop and PAHs in surface water was associated with the discharge from rivers passing through cities and/or industrial complexes. The NP contamination was associated with wastewater treatment plant (WWTP) effluents through outfalls as well as riverine discharge. Compared to ecotoxicological values, the concentrations of NPs from rivers, the mouths of rivers, and WWTP outfall areas exceeded guidelines, suggesting that hot spot areas may pose a potential risk to sensitive species.

• 전기학회논문지
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• 제57권9호
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• pp.1606-1611
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• 2008

Recently, The diagnosis techniques of electric facilities are developed on live line. This paper describes the discharge characteristics of polymer insulator(EPDM A type). Keeping the facilities in good working order, the goal of this paper will provide the information to enable user to easily judge conditions of facilities on the spot. The performance of polymer insulator is assessed from the KS C IEC 60270 and CEA LWIWG-01(96)(Tracking Wheel Test). As the results, UV generation patterns of polymer insulator grow like a jellyfish shape follow the ramping voltage. Discharging UVs are detected at about 31.25% of breakdown voltage. Just then, dimension of UV image is about $0.84cm^{2}$. The dimension of max. UV image is about $297.4cm^{2}$ at $160kV(V_{bd})$. The position of UV generation due to surface discharge of polymer insulator is the center of insulator in the early, then moved the ground side and the last, UV image moved through the junction part of source side. Surface of aged polymer insulator is cracked and faded due to arc. UV absorption spectrum of polymer insulator are appeared the C-H bond of scissoring vib. at $1014cm^{-1}$ and C=O bond of recombination structure. Also, recombined UV absorption peak such as C-H, N-H, and O-H is detected at the $3321cm^{-1}$. Through the paper, there are inspection data which are the relations between surface discharge of polymer insulator and UV detecting image.

• Journal of Advanced Marine Engineering and Technology
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• 제40권9호
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• pp.756-761
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• 2016

본 연구에서는 소형 단기통 4행정 농용 디젤엔진에 장착될 수 있는 플런저 직경 4 mm, 행정 7 mm의 연료펌프를 설계 및 제작하여 성능특성을 조사하는 것이 목적이다. 실린더 내 연소압력은 자체 제작한 모형 실린더 내에 질소가스를 사용하여 1, 6, 11, 16 및 21 bar의 배압을 형성시켜 모사했다. 실험에 있어서는 연료펌프 회전속도를 600, 800, 1000, 1200 및 1400 rpm로 변화시키면서 개발된 연료펌프의 토출구에서 1 cm 떨어진 지점의 토출압력, 30 cm 떨어진 지점의 송출압력과 송출유량을 배압에 대해 측정하였고, 펌프효율을 계산하였다. 그 결과, 연료펌프 회전속도가 증가하면 펌프의 송출유량은 증가하였고, 실린더 내의 압축압력인 배압이 증가하면 송출유량은 감소하였다. 또한, 연료펌프의 회전속도가 증가할수록 펌프효율이 감소되었고, 실린더 내의 배압이 증가함에 따라 펌프효율은 감소되었다.

• 한국수자원학회논문집
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• 제48권7호
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• pp.523-533
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• 2015

본 연구에서는 광정횡월류위어 설치 예정지 하류쪽 본류 흐름내에 소규모 보를 설치하는 경우, 위어의 월류량 개선효과를 수리실험을 통해 확인하였다. 위어는 선행연구를 통해 월류량 소통능력이 가장 우수한 것으로 확인된 1 : 1 사다리꼴 형상의 광정횡월류위어를 사용하였다. 위어높이와 수로높이는 각각 0.06 m와 0.2 m이고, 예비실험을 통해 보의 높이를 광정횡월류위어높이의 1/3인 0.02 m로 결정하였다. 하류쪽에 설치되는 보가 위어로 부터 떨어지는 거리에 대한 보의 높이의 비($B_h/L_b$)가 0.05, 0.025, 0.0167인 경우 월류량의 변화를 분석하였다. 보의 위치가 위어에 가까울수록 단위폭당 월류량이 많아졌으며, 각 8.1%, 5.4% 및 3.9% 증가하는 것으로 나타났다. 기존의 광정횡월류위어 유량계수식에 $B_h/L_b$를 매개변수로 추가하여 새로운 유량계수식을 제시하였다. 또한 선행연구 및 기존 연구자들의 실험자료와 본 실험의 연구자료를 비교하였으며, 측정된 월류량과 계산된 월류량을 비교하여 새롭게 제안하는 유량계수식의 적용성을 확인하였다.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.19-28
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• 2005

It is of great economic importance to minimize the cylinder wear and the consumption rate of cylinder oil in a large two-stroke diesel engine. The motor-driven cylinder lubricator was first developed fur a large two-stroke marine diesel engine made in $W{\ddot{a}}rtsil{\ddot{a}}a$ Switzerland Ltd. by the joint research of industry-university. In this study, the effects of revolution speed, plunger stroke and cylinder back pressure on maximum discharge and delivery pressures, delivery delay duration, and oil feed rate are experimentally investigated by the home-manufactured cylinder lubricator. The maximum discharge pressure with a spot of 0.03 m and the maximum loss pressure at spots of 5, 6.78 and i 0 m away from the end of lubricator slot are increased as plunger stroke, revolution speed and back pressure are elevated, and the delivery delay duration is shortened as plunger stroke, revolution speed and oil pipe length are increased. Also, oil feed rate is increased as plunger stroke and revolution speed are raised, but lowered as the back pressure is increased.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.63-69
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• 1999

The purpose of this study is to develop Water Quality Management System(WQMS), which performs calculating pollutant discharge and forecasting water quality with water pollution model. Operational water quality management requires not only controlling pollutants but acquiring and managing exact information. A GIS software, ArcView was used to enter or edit geographic data and attribute data, and MapObject was used to customize the user interface. PCI, a remote sensing software, was used for deriving land cover classification from 20 m resolution SPOT data by image processing. WQMS has two subsystems, Database Subsystem and Modelling subsystem. Database subsystem consisted of watershed data from digital map, remote sensing data, government reports, census data and so on. Modelling subsystem consisted of NSPLM(NonStorm Pollutant Load Model)-SPLM(Storm Pollutant Load Model). It calculates the amount of pollutant and predicts water quality. This two subsystem was connected through graphic display module. This system has been calibrated and verified by applying to Mokhyun stream watershed.

• 환경영향평가
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• 제8권4호
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• pp.1-12
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• 1999

본 연구의 목적은 지리정보시스템과 원격탐사를 이용하여 체계적이고 효율적인 수질관리 자료기반을 구축하고, 유역의 오염부하를 산정하여 장래의 수질을 예측할 수 있는 수질관리시스템을 구축하는데 있다. 수질관리를 위해서는 오염물질의 최적처리 등의 기술적 측면뿐만 아니라 수질환경에 관한 정확한 정보의 취득과 관리가 필요하다. 본 연구에서는 지형 및 속성정보의 입력 및 편집을 위해 ArcView 3.1을 사용하였으며, Avenue Script를 이용하여 사용자환경을 갖추도록 하였다. 또한, 토지피복분류를 위하여 20m 해상도의 SPOT XS영상을 대상으로 PCI 소프트웨어를 이용하여 분석하였다. 수질관리시스템은 데이터베이스 보조시스템과 Modeling 보조시스템으로 구성된다. 데이터베이스 보조시스템은 수치지형도에서 추출한 수치표고모델에서 분석한 유역분할도, 위성영상자료, 정부보고서, 통계자료들로 구성되며, Modeling 보조시스템은 강우 시와 비강우시의 유역의 오염부하량을 산정하고 수질예측을 하는 SPLM(Storm Pollutant Loading Model)과 NSPLM(Non-Storm Polutant Loading Model)으로 구성된다. 각각의 보조시스템은 그래픽 출력 부분과 결합하여 분석결과 및 유역현황을 표시하도록 설계되었다. 개발된 수질관리 시스템은 경기도 광주군 광주읍에 위치한 목현천 유역을 대상으로 적용되고 수정되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제39권3호
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• pp.286-291
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• 2015

Nd:YAG 레이저의 출력조절을 위하여 LLC 공진 컨버터를 사용하였다. ZVS(Zero Voltage Switching) 방식을 LLC 공진형 컨버터에 적용함으로써 스위칭 손실을 최소화하였다. 금속박막의 점용접과 같은 레이저가공에 있어서 단일 펄스에 대한 출력에너지가 가공특성을 결정하므로, 적절한 목표출력으로 단일펄스 당 50 [J]로 결정하였다. 따라서 레이저 출력은 출력전류를 변화시켜가면서 측정하고 분석하였다. 이 때, 전류는 커패시터의 충전전압의 크기에 따라 변한다. 이러한 결과로부터 충전 커패시터의 용량 12,000 [${\mu}F$], 반복율이 1 [Hz]일 때, 방전전압 620 [V], 방전전류 861 [A]에서 58.2 [J]의 레이저빔 최대 출력을 얻음으로써 전기에너지 입력에 대한 레이저빔 출력에너지 변환효율은 2.52%를 달성하였다.

• 환경영향평가
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• 제20권2호
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• pp.227-234
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• 2011

In the study, CE-QUAL-W2 was used and its examination and correction were conducted targeting 2001 and 2003 when the condition of rainfall was contradicted. Using the proved model in 2003, a scenario was implemented with management of locations for dewatering outlets and actual data for dam management in 1987 when inflow and outflow level were almost same. In case of the scenario which the location of dewatering outlets was 5m higher than usual location, exclusion efficiency for turbid water inflow at the beginning of precipitation was good. In case of the scenario which the location of dewatering outlets was 10m lower than usual location, exclusion efficiency for excluding turbid water remained in a reservoir after the end of precipitation. However, the scenario applying dam management data in 1987, exclusion efficiency was relatively low. In the scenario, power-generating water release spot at EL.57m for first four days after the beginning of precipitation, EL.52m for 5th to 8th and EL.42m from 9th days. An analysis of the scenario reveals that both excessive days exceeded 30 NTU and average turbidity levels were decreased comparing before and after the alteration on outlets. The average turbidity levels were decreased by minimum of 55% to maximum of 70% and 30NTU exceeding days were decreased by 45 days at maximum. Also, since it could exclude most of turbid water in a reservoir before the destatifcation, the risk for turbid water evenly distributed in a reservoir along with turn-over could be decreased as well.

• Journal of Biosystems Engineering
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• 제28권5호
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• pp.429-438
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• 2003

This study exploits the robot system which is necessary in gene study and bio-technology industry. As well, a DNA chip, which of use has been increased recently, can be manufactured with this system. The robot consists of a device spotting DNA on the silylated slide, a well plate, a bed for fixing well plates, devices of washing and drying the pin in DNA spotting .device, a distillation-water vessel, and a discharge vessel of wash water. We made the period of sticking DNA to the pin on the well plate to be 15 seconds. The spot size of DNA was set to be 0.28 mm on the average by bringing the slide into contact with pin during 1 second. If DNA is spotted in minimum space possible about 0.32mm, this system can stick about 8,100 DNA spots on the well plate with this rate. Analyzing the procedure: Movement starts, Pin washes, dries, and smears DNA on the well plate. Spotting DNA onto 12 chips took 2 minutes and 50 seconds.