• 한국해양학회지:바다
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• 제5권4호
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• pp.363-373
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• 2000

남서태평양 열수해역의 화학적 환경특성을 이해하기 위하여 수온, 염분, 투명도, pH, 영양염 및 황화수소 등을 분석하였다. 시료는 마누스분지의 12개 정점에서 CTD를 이용하여 채취하였다. 열수작용은 해수 및 암석간의 순환작용에 의해 이들의 물리, 화학적 특성을 변화시키고, 주변의 해수와는 특성이 다른 열수가 plume을 형성하여 해양으로 공급된다. 본 연구에서는 남서태평양 PACMANUS 해역과 Susu Knolls 해역에서 투명도 및 황화수소를 이용하여 열수작용에 의한 plume을 확인하였다 특히, 열수환경을 지시하는 지화학적 추적자인 황화수소는 0${\sim}$3.31 ${\mu}$M 범위와 평균 0.63${\mu}$M을 보였다. 열수작용에 의한 plume의 높이, 분출량 및 활동도는 저층해류 순환 등의 영향을 받으며 수층의 등밀도면을 따라 주변 해수로 확산된다. 결과적으로 연구 해역에서의 황화수소 농도 이상치는 열수작용에 의한 영향으로 판단되고, 따라서 PACMANUS 해역의 남북방향에 가장 큰 공급원이 있을 것으로 보인다.

• 한국패류학회지
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• 제18권1호
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• pp.53-59
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• 2002

충남 연근해역의 키조개 개체군을 대상으로 자원생태학적 특성을 규명하기 위해 1999년 4월부터 6월까지 조사가능한 212개 조사정점에 대해 현장조사를 실시하였다. 본 조사를 통해 서식환경 및 분포밀도와 특성을 살펴보고, 자원량을 추정하였다. 충남 연근해역은 3.9-75.9 m의 수심범위를 가지고, 평균수심이 28.5 m (SE = 0.97)이며, 저층의 환경특성은 평균수온 14.$0^{\circ}C$, 투명도 4.8 m, 부유물질 48.0 mg/l이었다. 해역의 88.0%가 사질함량이 50% 이상인 니사질과 사질로 구성되었으며, 조사해역에서 키조개 자원의 분포밀도는 18.0-30.8% m의 수심범위와 사질 함유량이 50% 이상인 니사질 해역에서 높다. 조사해역에서 키조개는 단위면적 40 m$^2$내에서 5 개체 미만이 어획된 해역은 전 서식면적의 54.9%, 5 개체 이상 10개체 미만의 개체가 어획된 해역은 9.9%, 10개체 이상 20개체 미만의 개체가 어획된 해역은 11.3%, 20개체 이상 50개체 미만의 개체가 어획된 해역은 16.9%, 50개체 이상이 어획된 해역은 7.0% 이었다.

• 한국환경과학회지
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• 제23권7호
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• pp.1321-1332
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• 2014

The key objective of this study was to evaluate trophic state and empirical water quality models along with analysis of fish trophic guilds in relation to water chemistry (N, P). Trophic state index (TSI), based on total phosphorus (TP) and chlorophyll-a (CHL), ranged between oligotrophic and hypereutrophic state, by the criteria of Nurnberg(1996), and was lower than the trophic state of total nitrogen (TN). Trophic relations of Secchi depth (SD), TN, TP, and CHL were compared using an empirical models of premonsoon (Pr), monsoon (Mo), and postmonsoon (Po). The model analysis indicated that the variation in water transparency of Secchi depth (SD) was largely accounted (p < 0.001, range of $R^2$ : 0.76-0.80) by TP during the seasons of Mo and Po and that the variation of CHL was accounted (p < 0.001, $R^2=0.70$) up to 70% by TP during the Po season. The eutrophication tendency, based on the $TSI_{TP}$ vs. $TSI_{N:P}$ were predictable ($R^2$ ranged 0.85-0.90, p < 0.001), slope and y intercept indicated low seasonal variability. In the mean time, $TSI_{N:P}$ vs. $TSI_{CHL}$ had a monsoon seasonality in relation to values of $TSI_{N:P}$ during the monsoon season due to a dilution of reservoir waters by strong monsoon rainfall. Trophic compositions of reservoir fish reflected ambient contents of TN, TP, and CHL in the reservoir waters. Thus, the proportions of omnivore fish increased with greater trophic conditions of TP, TN and CHL and the proportions of insectivore fish decreased with greater trophic conditions.

• 한국물환경학회지
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• 제24권6호
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• pp.741-749
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• 2008

Many small-scale ponds that serve as ecological habitat, recreation and irrigation are faced to eutrophication problem, which causes aesthetic nuisance and ultimately loss of their functions. Thus accurate evaluation of the trophic state of these ponds is essential to provide rational information to the stakeholders so that they can develop effective management actions. In this study, the trophic state of a small pond (Wonheung) that experiencing water quality degradation due to vicinity land development was assessed using various Trophic State Indexes (TSIs) and statistical analysis including Principal Components Analysis (PCA) based on the field monitoring data obtained from May to December, 2007. The results showed that the pond is under eutrophic state with average total nitrogen (T-N) and total phosphorus (T-P) concentrations of $708.1{\mu}g/L$ and $59.3{\mu}g/L$, respectively. The factor loading plot obtained from PCA showed distinct two influencing factors, PC 1 and PC 2. PC 1 was grouped by T-P, Chlorophyll a (Chl-a), suspended solids (SS), TN/TP ratio, and transparency that all strongly related to the eutrophication state, while PC 2 by temperature, conductivity, dissolved oxygen (DO) and turbidity that explains the seasonal water quality variations. The limiting factor was identified as light rather than phosphorus by both T-N/T-P ratio and TSI indexes analysis. The results and methodology adopted in this study can be used for water quality assessment for other small ponds and lakes.

• 한국환경과학회지
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• 제9권1호
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• pp.1-11
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• 2000

A study on the variational characteristics of water quality and phytoplankton biomass by principal component analysis(PCA) was carried out in Kogum-sudo from February to October in 1993. We analyzed PCA on biological factors such as chlorophyll a and phytoplankton cell numbers for centric and pennate diatoms, phytoflagellates, and total phytoplankton as well as physico-chemical factors as water temperature, salinity, transparency, dissolved oxygen(DO), saturation of DO, apparent oxygen utilization (AOU), chemical oxygen demand(COD), nutrient (ammonia, nitrite, nitrate, phosphate and silicate), N/P ratio and suspended solid(SS). The source of nutrients supply depended on the mineralization of organic matters and inputs of seawater from outside rather than runoff of freshwater. The phytoplankton biomass was changed within short interval period by nutrients change. And it was controlled by the combination of several environmental factors, especially of light intensity, ammonia and phosphate. The marine environmental characteristics were determined by the mineralization of organic matters in winter, by runoff of freshwater including high nutrients concentration in spring, by ammonia uptake and high phytoplankton productivity in summer, and phosphate supplied input seawater from outside of Kogeum-sudo in autumn. And Kogum-sudo was separated with 2 regions by score distributions of PCA. That is to say, one region was middle parts of straits which was characterized by the mixing seawater and the accumulated organic matters, other one region was Pungnam Bay and the water around Kogum Island which was done by high phytoplankyon biomass and productivity year-round.

• 한국전기전자재료학회논문지
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• 제22권3호
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• pp.262-268
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• 2009

We investigated the properties of inorganic diatomic films like silicon oxide ($SiO_2$) and zinc oxide (ZnO) and their composite films are packed as a passivation layer around Ca cells on glass substrates by using an electron-beam evaporation technique and rf-magnetron sputtering method. When these Ca cells are exposed to an ambient atmosphere, the water vapor penetrating through the passivation layers is adsorbed in the Ca cells, resulting in a gradual progress of transparency in the Ca cells, which can be represented by changes of the optical transmittance in the visible range. Compared with the saturation times for the Ca cells to become completely transparent in the atmosphere, the protection effects against permeation of water vapor are estimated for various passivation films. The thin composite films consist of$SiO_2$ and ZnO are found to show a superior protection effect from water vapor permeation compared with diatomic inorganic films like $SiO_2$ and ZnO. Also, this inorganic thin composite films are also found that their protection effect against permeation of water vapor can be significantly enhanced by choosing their suitable composition ratio and deposition method, in addition, the main factors affecting the permeation of water vapor through the oxide films are found to be the polarizability and the packing density.

• 미생물학회지
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• 제36권4호
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• pp.285-291
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• 2000

강진만 수역에서 이화학적 요인과 미생물군집의 변화를 조사하기 위해 영양염류, 수온, 투명도, 염분도, DO, COD 및 종속영양세균, 균류 그리고 분변성 대장균을 계절별로 분석하였다. 분석 결과 조사기간 동안 분변성 대장균군과 종속영양세균의 개체수 변화는 각각 16.1~166.0 CFU/ml 과 $5.0{\times}10^3$~$13.1{\times}10^3$CFU/ml의 범위를 보였다. 또한 이들 세균군집의 정점별 평균값은 다른 정점보다 담수유입 수역인 1번 정점에서 매우 높은 밀도를 보였다. 이화학적 조사와 미생물학적 조사 결과를 고찰했을 때 강진만 생태계는 계절에 따라 2~4개 요인에 의하여 조절되는 것으로 보이며, 주로 담수유입, 영양염류, 염분도 그리고 수온 등에 의하여 영향을 받는 것으로 판단되었다. 이들 결과로 볼 때 강진만의 생태계에서 환경 요인의 영향은 다른 만 (광양만, 진해만, 마산만 등)에 비해 상대적으로 적었던 것으로 사료된다.

• 한국물환경학회지
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• 제35권4호
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• pp.340-351
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• 2019

In this study, the relationship between trophic state indices was analyzed based on the monthly or weekly water quality data of 81 lakes (mostly man-made) in Korea between 2013-2017. Carlson's $TSI_C$ and Aizaki's $TSI_m$ were calculated using the summer (Jun.-Sep.) average data at the upper water layer. The previous Korean trophic state index ($TSI_{KO}$) and the newly suggested index ($TSI_{KON}$) was calculated using the annual average data at the whole layer and at the upper layer, respectively. While previous trophic state index (TSI) such as Carlson's TSI included logarithmic function, we devised newly Monod-type $TSI_{KON}$(Chl) that is 50 when half-saturation concentration of chlorophyll ${\alpha}$ ($Chl.{\alpha}$) measured by UNESCO-method is $10{\mu}gL^{-1}$. MMF-type $TSI_{KON}$(TP) was derived based on the relationship between TP and $Chl.{\alpha}$. A comprehensive $TSI_{KON}$ was decided as the larger one of the two $TSI_{KON}$ values. The range of previous TSI was usually 40-50 for the mesotrophic state, which seemed narrow to discriminate trophic characteristics of the class. The upper limits of $TSI_{KON}$ for oligotrophic, mesotrophic, and eutrophic state were set to 23, 50 and 75, respectively. Classification by $TSI_C$ and $TSI_m$ showed higher frequency of eutrophic class compared to $TSI_{KO}$ and $TSI_{KON}$. This means that the estimation by TSIs developed in foreign natural lakes can lead to distorted results in the classification of the trophic state of Korean lakes. This is due to the decrease of transparency by non-algal material and the reduction in phosphorus availability to algal growth, particularly in Monsoon period.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.394-394
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• 2012

We fabricated organic-inorganic superlattice films using molecular layer deposition (MLD) and atomic layer deposition (ALD). The MLD is a gas phase process in the vacuum like to atomic layer deposition (ALD) and also relies on a self-terminating surface reaction of organic precursor which results in the formation of a monolayer in each sequence. In the MLD process, 'Alucone' is very famous organic thin film fabricated using MLD. Alucone layers were grown by repeated sequential surface reactions of trimethylaluminum and ethylene glycol at substrate temperature of $80^{\circ}C$. In addition, we developed UV-assisted $Al_2O_3$ with gas diffusion barrier property better than typical $Al_2O_3$. The UV light was very effective to obtain defect-free, high quality $Al_2O_3$ thin film which is determined by water vapor transmission rate (WVTR). Ellipsometry analysis showed a self-limiting surface reaction process and linear growth of each organic, inorganic film. Composition of the organic films was confirmed by infrared (IR) spectroscopy. Ultra-violet (UV) spectroscopy was employed to measure transparency of the organic-inorganic superlattice films. WVTR is calculated by Ca test. Organic-inorganic superlattice films using UV-assisted $Al_2O_3$ and alucone have possible use in gas diffusion barrier for OLED.

• 한국환경과학회지
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• 제23권9호
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• pp.1537-1549
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• 2014

The objectives of this study were to analyze reservoir trophic state, based on Trophic State Index (TSI), spatial variation patterns of three zones (riverine, transition, and lacustrine zone), and empirical models through 20-years long-term data analysis. Trophic variables of TP and CHL-a were highest during the summer monsoon, and decreased along the main axis from the riverine to lacustrine zone. In the mean time, TN did not show the trend. Ratios of N:P and Secchi disc transparency (SD) increased from the riverine to lacustrine zone. The analysis of trophic state index (TSI) showed that mean TSI (TP) and TSI (CHL-a) were 62 and 57, respectively, and these values were highest in the transition zone during the summer. This zone should be managed well due to highest lake water pollution. The analysis of Trophic State Index Deviation (TSID) showed that algal growth was primarily limited by light penetration, and this was most pronounced in the monsoon season. The analysis of empirical models showed that the value of $R^2$, based on CHL-SD model, was 0.30 (p < 0.0001) in the transition zone and the $R^2$, based on TP-SD model, was 0.41 (p < 0.0001) in the transition zone.