• 한국막학회:학술대회논문집
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• 한국막학회 1996년도 제4회 하계분리막 Workshop (초순수 제조와 막분리 공정)
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• pp.121-147
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• 1996

Since 1980, the water quality of ultra-pure water has been rapidly improved, and presently ultra-pore water producing equipment for 64Mbit is in operation. Table 1 shows the degree of integration of DRM and required water quality exlmple. The requirements of the ultra-pure water for 64Mbit are resistivity: 18.2 MQ/cm or higher, number of particulates: 1 pc/ml or less (0.05 $\mu$m or larger). bacteria count: 0.1 pc/l or less. TOC (Total Organic Carbon, index of organic snbstance) : 1ppb or less, dissolved oxygen: 5ppb or less, silica: 0.5ppb or less, heavy metal ions: 5ppb or less. The effect of metals on the silicon wafer has been well known, and recently it has been reported that the existence of organic substance in ultra-pure water is closely related to the device defect, drawing attention. It is reported that if organic substance sticks to the natural oxidation film, the oxide film remaims on the organic substance attachment in the hydrofluoric acid treatment (removal of natural oxidation film). The organic substance forms film on the silicon wafer, and harmful elements such as metals and N.P.S., components contained in the organic substance and the bad effect due to the generatinn of silicon carbide cannot be forgotten. In order to remove various impurities in raw water, many technological develoments (membrane, ion exchange, TOC removal, piping material, microanalysis, etc.) have been made with ultra-pure water producing equipment and put to practical use. In this paper, technologies put to practical use in recent ultra-pure vater producing equimeut are introduced.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.106-106
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• 2018

Ecosystem service valuation is a crucial step for the sustainable management of watershed. In the context of various ecosystem services provided by watershed, this study, particularly deals with water yield computation in Bagmati Basin of Nepal. The water availability per population in Bagmati Basin is lowest compared to other basins in Nepal. Also, the rate of urbanization is rapidly growing over a decade. In this regard, the objectives of this study are 1) to compute the total water yield of the basin along with computation on a sub-watershed scale, and 2) Study the impacts of land use change on water yield based on CLUE-S model. For the study, Integrated Valuation of Environmental Services and Tradeoffs (InVEST), a popular model for ecosystem service assessment based on Budyko hydrological method is used to compute water yield. As well, CLUE-S model is used to study land use change, which is further related to study variation on water yield. The sub-watershed wise outcome of the study is expected to provide the guidelines for the effective and economic management of a watershed on a regional scale.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.40-45
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• 2007

Water regulators in New Zealand have recognised the need to adapt water allocation regimes and water permit conditions to reflect the likelihood of lower catchment yield on the east coast from 2030 due to climate change. Water management mechanisms to protect the environment and maintain the reliability of other water users are currently being applied or assessed in Marlborough province. These include seasonal water quota based on spring aquifer status, linking water use to environmental triggers to avoid seawater intrusion or spring depletion; and redefining water permit entitlements to account for recharge variability.

• 한국지형학회지
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• 제19권2호
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• pp.99-111
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• 2012

본 연구는 대전분지에 있어서 청동기시대에서 원삼국시대로의 이행과정에서 나타나는 주거지의 지리적(또는 지형적) 입지환경 변화와 그 원인을 밝히는 것이다. 이를 위하여 (1) '유적그룹(또는 주거지밀집유적)의 주거지 총수 비교'그리고 (2) '두 시대의 주거지를 모두 포함하고 있는 특정유적에서 주거지 총 수 비교'로 구분하여 시대변천에 따른 주거지의 표고, 경사도, 용수하천거리 및 용수하상비고 측면에서 입지환경을 상호 비교하였다. 그 결과는 다음과 같다. 1. 개별 인자의 변화를 보면, 표고는 상승했으며, 경사도는 증가했다. 용수하천거리는 소급하천의 경우 감소 내지 증가했으며, 중급하천의 경우 거의 차이가 없거나 증가했다. 그리고 용수하상비고는 소급하천의 경우 증가했으며, 중급하천의 경우 증가 내지 감소했다. 2. 개별 인자를 상호 비교하면, 경사도, 표고 및 용수하상비고의 증감이 대체로 유사한 경향을 띠며, 특히 경사도의 증가가 표고와 용수하상비고의 증가에 영향을 미치는 것으로 나타났다. 그리고 용수하천거리의 증감은 경사도, 표고 및 용수하상비고의 증감과 다른 경향을 나타내는 것으로 나타났다. 3. 이상으로부터 대전분지 내에 분포하는 저구릉의 미지형적 특성(예 : 경사도 특성)과 저구릉을 둘러싸고 있는 풍부한 수계환경이 서로 맞물려 당시의 주거지 입지선정에 영향을 미쳤다는 것을 알 수 있었다. 특히 당시 거주민들에게 주거지 입지 선정시 '경사도와 용수하천거리'가 '표고와 용수하상비고'에 비해 상대적으로 중요한 주거지 선정 인자였던 것으로 밝혀졌다.

• 한국수자원학회논문집
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• 제47권11호
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• pp.1017-1026
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• 2014

본 연구에서는 한강수계의 팔당댐 상류를 대상으로, 상류 댐들의 운영 및 하천수 사용이 하류구간의 유출에 미치는 영향을 정량적으로 분석하였다. SWAT-K 유역모형을 적용하여, 2001~2009년에 대해 상류댐 운영 및 하천 취수량 적용 유무에 따른 조건별 모의결과를 분석한 결과, 소양강댐과 충주댐 등 다목적댐 운영에 따른 방류량이 갈수기와 홍수기의 하류구간 유출에 가장 크게 영향을 주는 것으로 나타났다. 이로 인해 갈수량이 팔당댐 지점에서 $100.57m^3/s$, 북한강 종점 $33.01m^3/s$, 양평수위표 지점 $49.66m^3/s$만큼 증가하는 것으로 나타났다. 반면, 하천수 사용에 따른 영향은 북한강 지역은 거의 나타나지 않았으며, 남한강 지역도 양평수위표 지점에서 $0.98m^3/s$의 갈수량 감소가 나타나 팔당댐 유입량에는 큰 영향이 없었다. 따라서, 장기간의 유출 및 유황분석에서는 횡성댐과 같이 규모가 작은 댐 운영이나 하천수 취수 영향은 제외시켜도 무방할 것으로 생각된다. 그러나 물이용이 집중되는 특정기간의 정교한 수문해석이나 취수량이 많은 하천구간을 대상으로 하는 유출 분석에서는, 취수량은 물론 유역내 물이동량에 대한 정보가 필수적으로 고려되어야 할 것이다.

• 자원환경지질
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• 제28권2호
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• pp.165-176
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• 1995

Dongrae is one of the most famous hot spring resort area in the Republic of Korea. The water temperature ranges $50^{\circ}C{\sim}66$. The chemical composition of the thermal water is quite different from normal groundwater. $Na^+$ and $Cl^-$ are the main components, measured more than 75%, $Ca^{+{+}}$ is contained about 22% and the other ions such as $SO_4$ or $HCO_3$ are the minor components. The heat source is uprising along the fracture zone of granite which is indicated as a subsurface high temperature belt. During the research period of 1991~1992, the groundwater table was lowered down to the depth of about 100 m according to continuous increase of daily use of thermal water. The groundwater table was fluctuated with an amplitude of day, weak or seasion. The groundwater table was the lowest at 18:00 h in a day and also lowest at the weekend for the week period. There was a relavent relationship between drawdown and the amount of thermal water use on a long term base. To protect such a rapid drawdown of groundwater table, Dongrae resort area is now asked to take strong municipal control for the daily use of thermal water.

• 한국대기환경학회지
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• 제19권5호
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• pp.583-594
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• 2003

Ozone is an important atmospheric pollutant that is occurred in tropospheric chemical process and it also affects the human health and plants. For a correct application of abatement strategies for ozone, it is necessary to understand the factors that control atmospheric ozone removal by dry deposition processes. The present study investigates the numerical simulation of the dry deposition velocity (V$^{d}$ ) obtained from PNU/DEM (Pusan National University Deposition Model). PNU/DEM includes seasonal categories, meteorological factors, surface properties and land-use types and proposes for an accurate numerical computation. And, this study examines the ability of the PNU/DEM to compute V$_{d}$ of ozone over water surfaces and evaluates PNU/DEM by comparing its estimated V$_{d}$ to past observed V$_{d}$ over water. The parametrization was found to yield V$_{d}$ values generally in good agreement with the observations for the deciduous forest and the coniferous forest. Ozone is removed slowly at wet surface or water due to its low water solubility. Therefore V$_{d}$ values over water were lower than Vd values over the other surfaces. Comparison of PNU/DEM simulated V d values to observations of ozone V$_{d}$ that have been reported in the literature implies that PNU/DEM produces realistic results.

• Environmental Engineering Research
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• 제16권2호
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• pp.61-67
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• 2011

The water quality from nonpoint source run off results from different land use types has been studied. The construction of a buffer strip is one method of nonpoint source pollutant control. The Soil and Water Assessment Tool (SWAT) model has been applied to estimate the pollutant removal through the buffer strip. When the non-business land has been changed into grass to form a buffer-strip, the change of land use effects the results of the model according to measures of the water quality. The data from a water level station within the watershed in the years 2006 and 2007 was used for calibration and validation of the model. Under the rainfall conditions in 2007, the removal rates of SS, BOD, TN, TP were 11.5%, 9.5%, 1.2%, and 4.5%, respectively. During the rainy days, the removal rates at the buffer strip were 92.3% of SS, 91.2% of BOD, 82.4% of TN, and 83.5% of TP. The pollutants from nonpoint sources were effectively removed by over 80% as they passed through the buffer strips. Rainfall resulted in soil erosion, which led to an increase in the SS concentration, therefore, the construction of buffer strips protected the streams from SS inflows. Since TN concentrations are affected by the inflows of ground water and the N concentration of the rainfall, the removal rate of TN was relatively lower than for the other pollutants.

• International Journal of Concrete Structures and Materials
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• 제8권3호
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• pp.229-238
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• 2014

Typical high-performance concrete (HPC) mixtures are characterized by low water-cementitious material ratios, high cement contents, and the incorporation of admixtures. In spite of its superior properties in the hardened state, HPC suffers from many practical difficulties such as its sensitivity to early-age cracking (which is associated with self-desiccation and autogenous shrinkage). In this context, conventional curing procedures are not sufficiently effective to address these limitations. In order to overcome this issue, two strategies,which are based on the use of internal reservoirs of water, have been recently developed.One of these strategies is based on the use of lightweight aggregates (LWA), while the other is based on the use of superabsorbent polymers (SAP). This paper studies and compares the efficiency of the LWA and SAP approaches.Moreover, some of the theoretical aspects that should be taken into account to optimize their application for internal curing of HPC are also discussed. Two fine LWA's and one SAP are studied in terms of autogenous deformation and compressive strength. Increasing the amounts of LWAor SAP can lead to a reduction of the autogenous deformation and compressive strength (especially when adding large amounts). By selecting appropriate materials and controlling their amount, size, and porosity, highly efficient internal water curing can be ensured.

• 한국조경학회지
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• 제28권4호
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• pp.117-124
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• 2000

This paper presents a design of urban waterfront park using agricultural reservoir in urban fringe area to meet increasing leisure demand for urban resident and to improve resident's quality of life through preventing the reservoir from urban use after reclamation. The site, Unam-Ji, is located on northern part of Taegu metropolitan area, having 17,791 square meters. We had designed this park from 1997 to 1998. After analyzed such factor as accessibility, current land uses, topography, hydrology, vegetation and landscape, climate, and soil, we constructed basic design scheme and principes such as conservation of natural resources, meeting user's recreation demands, providing opportunities for experiencing natural process, integrating naturalness and amenity of the site, and comfortable place with natural dynamism. Based on these principles, we have designed Unam-Ji waterfront park having intrinsic characteristics of the site, maintaining water quality and ecological restoration and improving water-based recreation opportunities. After evaluation of such criteria of design alternative as land use and circulation, spatial organization, convenience for use of and maintenance, conservation of natural environment, and degree of achieving planning and design goals, and maintaining landscape, we have visualized and formalized waterfront park in design process, which is consisted of four squares-- green square for multiple uses, water-based recreation square, pedestrian roads and decks near waterfront, performance square and fords near waterfront. In conclusion, this waterfront park design contributes to improve quality of urban development through preserving agricultural as an important component of urban water system and provide important planning and design implications in urban open space planning.