• The Korean Journal of Ecology
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• 제23권1호
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• pp.59-64
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• 2000

진해만의 중금속 오염도를 평가하기 위해 해저퇴적물, 해수 및 참굴의 중금속 농도를 측정하였다. 해저퇴적물내 카드뮴, 코발트, 구리, 니켈, 납, 아연의 농도범위는 0.1∼2.4, 12.6∼14.4, 25.3∼92.3, 32. 4∼93.5, 24.1∼81.2, 124∼477 ㎍/g 으로 나타났다. 인간의 산업활동과 관련된 카드뮴, 구리, 납, 아연의 농도는 마산 내만에서 높게 나타났다. 해수내의 용존성 카드뮴, 코발트, 구리, 니켈, 납, 아연의 농도범위는 ＜0.010∼0.043, 0.008∼0.120,0.31∼0.90,0.25∼3.10, 0.010∼0.142,0.27∼9.04 ㎍/L로 나타났다. 해수의 카드뮴, 구리, 납, 아연의 농도도 퇴적물에서처럼 마산 내만에서 높게 나타났으므로 마산만이 진해만의 주오염원임을 알 수 있었다. 참굴의 아연, 구리, 카드뮴, 납, 코발트, 니켈 둥의 생물농축계수(BCF)는 647373, 280861, 145069, 44559, 13524, 2745 순으로 나타났으며, 다른 이매패류에 비해 강한 중금속 축적종으로 나타났다.

• 한국표면공학회지
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• 제45권6호
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• pp.264-271
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• 2012

Due to the good corrosion resistance and machinability, copper alloy is commonly employed for shipbuilding, hydroelectric power and tidal power industries. The Cu alloy, however, has poor durability, and the seawater application at fast flow condition becomes vulnerable to cavitation damage leading to economic loss and risking safety. The HVOF(High Velocity Oxygen Fuel) thermal spray coating with WC-10Co4Cr were therefore introduced as a replacement for chromium or ceramic to minimize the cavitation damage and secure durablility under high-velocity and high-pressure fluid flow. Cavitation test was conducted in seawater at $15^{\circ}C$ and $25^{\circ}C$ with an amplitude of $30{\mu}m$ on HVOF WC-10Co4Cr coatings produced by thermal spray. The cavitation at $15^{\circ}C$ and $25^{\circ}C$ exposed the substrate in 12.5 hours and in 10 hours, respectively. Starting from 5 hours of cavitation, the coating layer continued to show damage by higher than 160% over time when the temperature of seawater was elevated from $15^{\circ}C$ to $25^{\circ}C$. Under cavitation environment, although WC-10Co4Cr has good wear resistance and durability, increase in temperature may accelerate the damage rate of the coating layer mainly due to cavitation damage.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 추계학술대회 논문집
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• pp.325-325
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• 2015

• 한국표면공학회지
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• 제50권2호
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• pp.91-97
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• 2017

The aim of this paper is to investigate the characteristics of electrochemical corrosion with the plasma ion nitriding temperature for 16Cr-10Ni-2Mo stainless steel. The corrosion behavior was analyzed by means of galvanostatic experiment in natural seawater that applied various current density with plasma ion nitriding temperature parameters. In result of galvanostatic experiment, relatively less surface damage morphology and the less damage depth was observed at a nitrided temperature of $450^{\circ}C$ that measured the thickest nitrided layer(S-phase). On the other hand, the most damage depth and unified corrosion behavior presented at a temperature of $500^{\circ}C$.

• 한국표면공학회지
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• 제50권6호
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• pp.504-509
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• 2017

In order to improve corrosion resistance for cast stainless steel in seawater, the characteristics of corrosion resistance after plasma ion nitriding was investigated. Plasma ion nitriding process was conducted in a mixture of nitrogen of 25% and hydrogen of 75% at substrate temperature ranging from 350 to $500^{\circ}C$ for 10 hours using pulsed-DC glow discharge plasma with working pressure of 250 Pa in vacuum condition. Corrosion tests were carried out for as-received and plasma ion nitrided specimens. The corrosion characteristics were investigated by measurement of weight loss and observation of surface morphology. In anodic polarization experiment, relatively less damage depth and weight loss were presented at a nitrided temperature of $400^{\circ}C$, attributing to the formation of S-phase.

• 한국해양학회지:바다
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• 제20권1호
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• pp.29-35
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• 2015

해수 중 용존 영양염은 해양 내 물질순환을 이해하는 가장 기초적인 자료로 전 지구적 환경변화를 감지하는데 필수 생지화학 성분으로 그 중요성이 인식되고 있다. 분석능력이 다양한 연구자들에 의해서 상이한 시공간에서 측정된 용존 영양염 자료의 상호 비교를 위해 영양염 표준물질의 필요성이 증가하고 있다. 본 연구는 경기도 시화호 내측연안, 울진의 인근 연안 표층수와 동해 울릉분지 표층과 1500m에서 채취된 해수를 여과, 멸균하여 제조한 영양염 표준물질의 균질성과 안정성에 대하여 다루었다. 본 연구에서 제작된 영양염 표준물질은 해외에서 제조되는 영양염 표준물질과 유사한 균질성을 가지고 있다. 제조 후 3-13개월 동안 영양염 농도가 일정한 방향으로 감소하거나 증가하는 경향이 관측되지 않았으며 이 보다 더 긴 기간 동안의 안정성은 지속적인 모니터링이 필요하다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.1895-1899
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• 2006

해안지역에서는 해수와 담수의 밀도차, 조석에 의한 해수면변화등과 같은 자연적 요인과 양수, 하구에서의 골재채취, 대규모 간척사업등의 인위적 요인에 의해서 해수가 육지부로 침투되는 현상이 발생한다. 본 연구에서는 양수가 지하수의 염분농도변화에 미치는 영향을 분석하였다. 모의결과, $200m^3/day$이상 양수시에는 지하수위의 저하보다는 횡방향흐름이 가속화 됨에 따라 밀도차에 의한 흐름과 횡방향흐름 유속이 합쳐져서 해수의 급격한 유입으로 TDS농도가 증가하는 것으로 나타났다. 결론적으로 기 관측된 점자료를 이용하여 3차원 공간분포상에서 양수에 따른 염분농도의 변화를 가시적으로 확인 할 수 있으며, 이를 통하여 해안지역에서 해수침투로 인한 재해를 막고 지하수를 보다 안전하게 이용하기위한 적정양수량을 제안할 수 있을 것으로 기대된다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.335-339
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• 2003

The estimation of seawater intrusion into deep aquifers has been becoming an important subject in terms of site characterization for geological disposal of radioactive waste. Conventional direct-current resistivity methods have been used for ground water explorations and recently have been applied to environmental problems. However, electromagnetic methods are more practical and useful for such a deep investigation. We consider audio-frequency magnetotelluric (AMT) and surface-to-borehole electromagnetic (EM) tomography methods as promising tools for the investigation of deep aquifer. These methods were tested in the Hasunuma area, Chiba Prefecture, Japan. Although the study area is in an urban area, high-quality AMT data were acquired, which was mainly accomplished by night-time data recording and remote-reference data processing. One-dimensional inversion results of the AMT data revealed two extremely conductive zones, which is consistent with the electrical conductivity profile of pore water in core samples. It can be interpreted as the seawater intrusions into both zones. However, the chemical analysis of the groundwater sampled in the deep zone suggests that this groundwater must be fossil seawater that had been confined during sedimentation processes. In addition, the permeability coefficient of the deep layer is very low. Thus the deep conductive zone corresponds to the fossil seawater regarded as being difficult to flow.

• Corrosion Science and Technology
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• 제20권2호
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• pp.85-93
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• 2021

The corrosion damage of materials in marine environment mainly occurs by Cl^- ions due to the breakdown of passive films. Additionally, various characteristics in seawater such as salinity, temperature, immersion time, flow rate, and biological activity also affect corrosion characteristics. In this study, the corrosion characteristics of stainless steels (STS 304 and STS 316L) and anodized aluminum alloys (AA 3003 and AA 6063) were evaluated with seawater temperature parameters. A potentiodynamic polarization experiment was conducted in a potential range of -0.25 V to 2.0 V at open circuit potential (OCP). Corrosion current density and corrosion potential were obtained through the Tafel extrapolation method to analyze changes in corrosion rate due to temperature. Corrosion behavior was evaluated by measuring weight loss before/after the experiment and also observing surface morphology through a scanning electronic microscope (SEM) and 3D microscopy. Weight loss, maximum damage depth and pitting damage increased as seawater temperature increased, and furthermore, the tendency of higher corrosion current density with an increase of temperature attributed to an increase in corrosion rate. There was lower pitting damage and lower corrosion current density for anodized aluminum alloys than for stainless steels as the temperature increased.

• Corrosion Science and Technology
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• 제6권4호
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• pp.177-185
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• 2007

The purpose of this study is to evaluate freezing-thawing and surface scaling resistance in order to examine the frost durability of concrete in a chloride-inherent environment. The mixing design for this study is as follows: 3 water binder ratios of 0.37, 0.42, and 0.47; 2-ingredient type concrete (50% OPC concrete and 50% ground granulated blast-furnace slag), and 3-ingredient type concrete (50% OPC concrete, 15% fly ash, and 35% ground granulated blast-furnace slag). As found in this study, the decrease of durability was much more noticeable in combined deterioration through both salt damage and frost damage than in a single deterioration through either ofthese; when using blast-furnace slag in freezing-thawing seawater, the frost durability and surface deterioration resistance was evaluated as higher than when using OPC concrete. BF 50% concrete, especially, rather than BFS35%+FA15%, had a notable effect on resistance to chloride penetration and freezing/expansion. It has been confirmed that surface deterioration can be evaluated through a quantitative analysis of scaling, calculated from concrete's underwater weight and surface-dry weight as affected by the freezing-thawing of seawater.