• 한국환경과학회지
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• 제6권6호
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• pp.595-604
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• 1997

To investigate characteristics of biogeochemical environment of the Korea Deep Ocean Study(KODOSI area in the northeast Pacific Ocean, we preferentially measured Inorganic nutrients and fluorescent organic matters. Typically. the permanent thermocline was well developed at the depth of 200~1000m In the study area. Nitrate. phosphate and silicate were low In the surface mixed layer and Increased with depth. N/P and N/Si showed 15 and 0.2 respectively In the deeper layer. Two fluorophores, biomacromolecule(protein-like) and geomacromolecule (humid-like) , were observed by three dimensional fluorescence excltatlon/ emission spectra matrix. Biomacromolecule(maximum fluorescence at $Ex_{280m}/Em_{330nm}$) ranged from 41.9 to 147.0 TU with its maximum In the surface mixed layer and minimum in deeper water, This is a same trend that has been reported for DOC in the equatorial Pacific. This suggests that biomacromolecule might be labile and converted to refractory humic substance after bacterial degradation In the deeper layer. On the contrary, geomacromolecule(maximum fluorescence at $Ex_{330m}/Em_{430m}$), ranged from 7.6 to 46.5 QSU, showed minimum in the surface nixed layer(euphotic zone) Implying photodegradation and then increased with depth at all stations. In the characteristics of vertical profiles, the relationship between biomacromolecule and geomacromolecule showed negative correlation. Such trend can be attributed to biochemical regeneration or formation of fluorescent materials accompanying oxidation and rennnerallzation of settling organic matter.

• 한국대기환경학회지
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• 제24권4호
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• pp.383-392
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• 2008

In order to clarify the influence of the change of urban surface albedo on mesoscale meteorological factors during the summertime, numerical experiments with various albedo of urban surface were carried out. Numerical model used in this study is PSU/NCAR MM5 V3.6. As a result of the numerical simulation intended of Busan assumed the increase of albedo of roofs, buildings, or roads, the increase of albedo can make decrease radiation effect of surface, so that it caused drops in ambient air temperature from $0.5^{\circ}C$ to $1^{\circ}C$ on the average, and the downtown of Busan formed along the trough presented a substantial drop in ambient air temperature about $1.5^{\circ}C$. Modeling studies suggest the increased surface albedo in urban area can reduce surface and air temperatures near the ground and affect related meteorological parameters such as winds and the depth of the mixed boundary layer.

• 공업화학
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• 제18권2호
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• pp.183-187
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• 2007

대구경 실리카 입자를 사용하여 실리카/티타니아 코어-쉘 입자를 제조하였으며, 반복 코팅에 의해 티타니아 코팅 층의 두께를 조절하였다. 티타니아 코팅층의 두께는 코팅횟수를 1회에서 3회로 늘림에 따라 8 nm에서 38 nm로 증가하였다. 코팅 후 입자의 표면은 티타니아 코팅 층으로 인해 거칠어 졌으며 비표면적도 3~25배 증가하였다. 티타니아가 코팅된 실리카 입자의 특성은 FE-SEM, 제타전위기, BET, XRD 등을 이용해 분석하였다.

• Nuclear Engineering and Technology
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• 제32권3호
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• pp.274-282
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• 2000

The simulation of water balance was conducted for suggested four alternative multi-layer cover design of near-surface radioactive waste disposal facility under domestic climate condition. The analysis was also conducted for the most favorable one out of four alternative cover design under conservative scenarios. Until 100 years after closure of disposal vault, the infiltration flux for the most favorable cover design was negligible even under doubling of the ambient precipitation condition. When the degradation of asphalt and geomembrane after 100 years of closure was considered, the infiltration flux significantly increased almost to the design criteria of cover system in I' Aube disposal facility. And it was found that the hydraulic conductivity of bentonite/sand as a bottom barrier should be no greater than 1$\times$10$^{-7}$ cm/sec recommended by U.S. EPA.

• 한국환경보건학회지
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• 제14권1호
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• pp.47-53
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• 1988

This study was performed to investigate a seasonal and vertical variation of the nutrients, water temperature, pH, DO, BOD, COD in Sukchon lake from May 1985 to Jan. 1986. The results were as follows. 1. Vertical descent of water temperature was the remarkable situation on Jul. and difference between surface layer and bottom layer was 3.5$\circ$C. 2. The value of pH was average 8.0 in both lake. The value of pH in the winter was average 7.6, and Summer was average 8.3. 3. The contents of dissolved oxygen was the highest value (13.0mg/l in surface layer on Jan. and the lowest value (8.1mg/l in bottom layer on Ul. 4. The contents of PO$_4$-P, NH$_3$-N, NO$_3$-N and T-N were 0.03~O.17mg/l 0.12~0.34mg/l 0.36~0.91mg/l and 0.76~1.37mg/l respectively.

• Environmental Analysis Health and Toxicology
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• 제22권2호통권57호
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• pp.129-135
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• 2007

Polycyclic aromatic hydrocarbons(PAHs) have been analyzed to assess vertical distribution of them with different land uses. The soils were collected from three layers; surface $(0{\sim}5cm)$, intermediate $(6{\sim}10cm)$, and deep $(11{\sim}15cm)$ layer, respectively considering land use; paddy, upland, and mountain in each site. Total 89 samples of soil from 10 sites were analyzed. Overall mean of ${\sum}PAHs$ were 137 (range $8.87{\sim}625{\mu}g\;kg^{-1}$), 203 (range $16.5{\sim}645{\mu}g\;kg^{-1}$), and $83.4{\mu}g\;kg^{-1}$ (range $6.65{\sim}667{\mu}g\;kg^{-1}$) for paddy, upland, and mountain soil, respectively. The dominant PAHs were fluoroanthene/benzo(b)fluoroanthene>pyrene>indeno(1, 2, 3-cd) pyrene in paddy, fluoroanthene/pyrene>benzo(b)fluoroanthene>chrysene in upland, and benzo(b)fluoroanthene>pyrene>chrysene in mountain soil, whereas the profile was quite similar for each other except that indeno(1, 2, 3-cd)pyrene and benzo(ghi)perylene are relatively higher in the paddy soils. Although the concentration gradient by depth was not observed in the paddy and upland soils because perturbation of soil layer by tillage, significant decrease was in the deep layer relative to the surface and intermediate layer. However, the concentration gradient of PAHs by soil depth was clearly shown in mountain soil without experiencing disturbance of tillage.

• 한국환경과학회지
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• 제29권12호
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• pp.1223-1237
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• 2020

This study focused on comparing the meteorological conditions in the Atmospheric Boundary Layer (ABL) on high-event days and non-event days in the Seoul Metropolitan Area (SMA). We utilized observed PM10 and meteorological variables at the surface as well as at the upper heights. The results showed that high-event days were consistently associated with lower wind speed, whereas wind direction showed no particular difference between high-event and non-event days with frequent westerlies and northwesterlies for both cases. During high-event days, the temperature was much warmer than the monthly normal values with a sharp increasing trend, and Relative Humidity (RH) was higher than the monthly normal, especially on high-event days in February. During high-event days in spring, a double inversion layer was present at surface and upper heights. This indicates that stability in the multi-layer is an important indicator of higher PM10 concentrations. Net radiation in spring and winter is also closely associated with higher PM10 concentrations. Strong net radiation resulted in large sensible heat, which in turn facilitated a deeper mixing height with diluted PM10 concentrations; in contrast, PM10 concentrations were higher when sensible heat in spring and winter was very low. We also confirmed that convective and friction velocity was higher on non-event days than on high-event days, and this was especially obvious in spring and winter. This indicated that thermal turbulence was dominant in spring, whereas in winter, mechanical turbulence was dominant over the SMA.

• Ocean Science Journal
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• 제41권4호
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• pp.255-260
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• 2006

Long-term variability in the intermediate layer of the eastern Japan Basin has been investigated to understand the variability of water mass formation in the East Sea. The simultaneous decrease of temperature at shallower depths and oxygen increasing at deeper depths in the intermediate layer took place in the late 1960's sand the mid-1980's. Records of winter sea surface temperatures and air temperatures showed that there were cold winters that persisted for several years during those periods. Therefore, it was assumed that a large amount of newly-formed water was supplied to the intermediate layer during those cold winters. Close analysis suggests that the formation of the Upper Portion of Proper Water occurred in the late 1960's and the Central Water in the mid-1980's.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.399-402
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• 2004

An aquifer thermal energy storage (ATES) model is simulated by FEFLOW according to the scenario of heat pump operation in two layered confining aquifer. The scenario is consisted of 4 steps: 90 days pumping (west well) and waste water injection (east well: 35 $^{\circ}C$), 90 day s stop, 90days pumping (east well) and waste water injection (west well: 5 $^{\circ}C$), and 95 days stop. The injection of the waste water is limited in the second layer and the first layer is aquitard. The temperature distribution at the surface shows low difference with reference temperature and opposit aspect with that of the second layer because the thermal transition through the first layer is very slow. Even though the simulated thermal transition in the aquifer system have a difference with real ATES system, optimal design and operate system can be developed with field tests and operational experience.

• Corrosion Science and Technology
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• 제2권4호
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• pp.194-196
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• 2003

In this paper, a newest kind of anti-atmospheric corrosion method is introduced. This method does not adopt organic coating, plastic layer or metal plating, instead it adopts a kind of aqueous emulsion containing numerous tine solid compounds that are absorbed onto the component surface, which play the role of anti-electrochemical corrosion.