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        검색결과 651

        621.
        2001.12 KCI 등재 서비스 종료(열람 제한)
        Satellite data, with sea surface temperature(SST) by NOAA and sea level(SL) by Topex/poseidon, are used to estimate characteristics on the variations and correlations of SST and SL in the East Asian Seas from January 1993 through May 1998. We found that there are two climatic characteristics in the East Asian seas: the oceanic climate, the eastern sea of Japan, and the continental climate, the eastern sea of China, respectively. In the oceanic climate, the variations of SL have the high values in the main current of Kuroshio and the variations of SST have not the remarkable seasonal variations because of the continuos compensation of warm current by Kuroshio. In the continental climate, SL has high variations in the estuaries(the Yellow River, the Yangtze River) with the mixing the fresh water and the saline water in the coasts of continent and SST has highly the seasonal variations due to the climatic effect of continents. In the steric variations of summer, the eastern sea of Japan, the East China Sea and the western sea of Korea is increased the sea level about 10∼20㎝. But the Bohai bay in China have relatively the high values about 20∼30㎝ due to the continental climate. Generally the trends of SST and SL increased during all periods. That is say, the slopes of SST and SL is presented 0.29℃/year and 0.84㎝/year, respectively. The annual and semi-annual amplitudes have a remarkable variations in the western sea of Korea and the eastern sea of Japan. In the case of the annual peaks, there appeared mainly in the western sea of Korea and the eastern sea of Japan because of the remarkable variations of SL associated with Kuroshio. But in the case of the semi-annual peaks, there appeared in the eastern sea of Japan by the influence of current, and in the western sea of Korea by the influence of seasonal temperature, respectively. From our results, it should be believed that SST and SL gradually increase in the East Asian seas concerning to the global warming. So that, it should be requested to the international co-operation against to the change of the abnormal climate.
        622.
        2001.12 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 군말뚝 교각 주위에서의 세굴특성을 실험을 통하여 파악하였다. 실험은 4개, 9개, 15개, 35개의 파일로 구성된 군말뚝에 대해 수행하여 파일수, 유속, 접근각에 따른 세굴형상, 최대세굴심의 깊이 및 위치의 변화를 살펴보았다. 실험결과에 의하면, 4개 및 9개로 구성된 군말뚝의 경우 유속비와 상관없이 단일교각의 최대세굴심과 흡사하였고, 15개와 35개로 구성된 군말뚝의 경우 유속비가 증가함에 따라 최대세굴심도 급격히 증가하여 단일교각 세굴
        623.
        2001.12 KCI 등재 서비스 종료(열람 제한)
        As a part of the development program of Ulsan Port, construction of detached breakwater is planned. In Ulsan Port, several oil-buoys exist. If the detached breakwaters have been constructed, these oil-buoys will be located within 1 km from the planned breakwaters. Construction of the breakwaters gives rise to changes of wave conditions on the sea areas, especially in front of the breakwater and it affects mooring of tankers, which supply oil to the oil-buoy In this study, in order to calculate standing wave distribution after construction of a breakwater, numerical model is proposed based on unsteady mild slope equation. Calculation is performed by testing different wave heights, directions and reflection coefficients of breakwater. In addition, the influence to working condition of tanker moored at the oil-buoy is evaluated by using measured wave conditions and calculated results.
        626.
        2001.03 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to suggest the landscape potential index for visualizing landscape information in the conservation of hilly landscape in urban fringe. For the visual and quantitative approach to topological landscape assessment, numerical entity data of DEM(digital elevation model) were processed with CAD-based utilities that we developed and were mainly focused on analysis of visibility and visual sensitivity. Some results, with reference in assessing greenbelt area of Eodeung Mt. in Gwangju, proved to be considerable in the landscape assessment of suburban hilly landscapes. 1) Since the viewpoints and viewpoint fields were critical to landscape structure, randomized 194 points(spatially 500m interval) were applied to assessing the generalized visual sensitivity, we called. Because there were similar patterns of distribution comparing to those by 56 points and 18 Points given appropriately, it could be more efficient by a few viewpoints which located widely. 2) Regressional function was derived to represent the relationships between probabilities of visibility frequency and the topological factors(topological dominance, landform complexity and relational aspect) of target field. 3) Visibility scores of each viewpoint were be calculated by summing the visual sensitivity indices within a scene. The scores to the upper part including ridge line have been more representative to overall distributions of visual sensitivities. Also, with sum of deviations of sensitivity indices from each single point's specific index to the weighting values of view points could be estimated rotationally. 4) The deviational distributions of visual sensitivity classes in the topological unit of target field were proved to represent the visual vulnerability of the landform. 5) Landscape potential indices combined with the visual sensitivity and the DGN(degree of green naturality) were proposed as visualized landscape information distributed by topological unit.
        630.
        2000.02 KCI 등재 서비스 종료(열람 제한)
        In this study, we investigated the site feasibility for the construction of the incineration facilities in Won Ju City. To assess the environmental impact of its construction, we examined the current status of air quality in the selected candidate sites and predicted the extent of air quality change upon its operation through modification of stack type. If the stack height is assumed to be 70 m, the concentrations of SO2 and dioxin in the surrounding area were predicted to increase by 0.05 ppb and 0.09 pg/㎥, respectively. The impact of its operation was assessed and compared among different sites. According to this analysis, more impact was expected from the residential area for the Dan-Gye site than from agricultural areas of the Kwan-Sul and Sa-Je site.
        631.
        2000.02 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to propose section designs for the ecological improvement of streams in rural villages in Korea. According to the survey about ecological conditions of rural streams of 10 selected rural villages (sep., 1996), the streams could be classified into three divisions(upstream, inner village, downstream), and the average width of streams was 9m, and the height of banks 3.1m. The slopes of basin were 7.33%, 2.67%, 1.39% at upstream, inner village, downstream respectively. The survey about the residents' usage of stream and the preferred activities(jun., 1997) showed that the streams were most frequently used for the supply of agricultural water use(39%), for the washing(15%) and for the recreation and rippling(10%), etc.. Three standard designs were presented for upstream, inner village, and downstream, and three standard sections were made by each designs. For the upstream division, it was designed to be used for the recreational activities in summer and the major stream bank materials were base rock and existing boulders with least artificiality. As the streams in the residential area were expected to be frequent access and used by the residents, most facilities for the streamside activity such as waterfront, water holes, shallows, walk were concentrated in this part with some artificiality. The downstream was designed for the agricultural activities such as water supply, space for the preparation of work and some break during the work.
        632.
        1999.12 서비스 종료(열람 제한)
        It is essential for port planning, coastal zone management and environmental impact study to analyze the variation of current and water quality due to the development of water area and discharged water from estuary barrage and basin etc. Mokpo sea area downstreams from a long river and two large basins, the Yongsan river and Yongam-Kumho basins discharging much of water through water gates for the purpose of flood control and prohibition of salt intrusion to the inland fresh water area. In this study, the numerical calculations were carried out for the analysis of diffusion characteristics due to discharging operation, adapting the results of tidal current simulation ADI methord is applied to the governing equation for the movement of sea water and diffusion and 6-point method to the advection terms of diffusion equation. As the results of this study, it is known that the discharging operation causes increasing and/or decreasing of current velocity and enlarging and/or depressing of pollutant diffusion limits depending on the distance from the discharging gates and the mode of discharging operation. To utilize these result, the linked gate operation and the method increasing exchange of sea water must be considered.
        633.
        1999.08 KCI 등재 서비스 종료(열람 제한)
        We will calculate concentration of air pollutants using ISCST3, FDM and AERMOD of models recommended in U. S. EPA which are able to predict concentration of short term for point source, complex like industrial complex, power plant and burn-up institution. Before executing model, as analyzing computational result of many cases according to selecting of input data, we will increasing predictable ability of model in limit range of model. Especially, we analyzed three cases - case of considering various emission rate according to time scale and not, case considering effect of atmospheric pollution materials removed by physical process. In our study, after comparing and analyzing results of three model, we choose the atmospheric dispersion model reflected well the characteristic of the area. And we will investigate how large the complex pollutant sources such as industrial complex contribute to atmospheric environment and air quality of the surrounding the area as predicting and estimating chosen model.
        634.
        1999.08 KCI 등재 서비스 종료(열람 제한)
        This studys concerns with a critical issues of urban and rural integration for rurban development. Todays, many of urban-rural integrated cities are confronted with the negative effects of administrative boundary integration. The first problem is induced from the developmental gaps and different residential demands between the core-city and peripheral-county. The second problem is social-economic and administrative unification costs neglected. The third problem is the environmental pollutions and degradations in peripheral-county by rapid urbanization. The forth problem is the inequality of the public services and regional investments in the urban-rural Integrated cities. The fifth problem is the administrative relation and financial distribution between core-city and residual province when the urban-rural integrated core-city becomes large urban city. The results of the questionnaire analysis as follows. The first point, the preference of administrative boundary integration is different in intra-areas of urban-rural integrated county by it's location. The second point, the diversity of preference of residents depends on theirs job, age, resdential period, education and income level. So, administrative boundary integration must consider the many important factors which affect the socio-economic situations between the core-city and peripheral-county. In conclusion, residents' preference for the admistrative boundary integration depends on their situation without rational approach for macro regional development. In this contexts, comprehensive approach for the urban-rural administrative boundary integration is needed in consistent with rapid change of local government's functions.
        635.
        1999.06 KCI 등재 서비스 종료(열람 제한)
        연직벽 교대에서의 국부세굴심을 측정한 실험실 자료들이다. 이들 자료들은 교대의 끝단형상, 정렬각도, 흐름수심, 흐름경사에 따라 국부 세굴심의 영향을 주는 자료들로 포함한다. 모형교대 끝단 형상이 직사각형, 타원형, 끝단을 깎아낸 직사각형, 예연형인 교대에서 국부세굴의 양상이 실험적 연구에 의하여 분석되었다. 실험들은 4개의 교대 형상에 대하여 흐름수심을 약 1cm씩 증가시켜서 이동상 세굴 조건하에 실험을 하였다. 수로의 하상경사는 0.01%, 0.03%
        636.
        1999.06 서비스 종료(열람 제한)
        Mokpo coastal area is connected to the adjacent a long river and two large basins. It is essential for port planning coastal zone management and environmental impact study to analyze the data related to the ship operation and variation of current and water quality due to the development of water area including dredging reclamation and estuary barrage. The Yongsan river estuary weir and Yongam-Kumho basins discharge much of water through water gates for the purpose of flood control and prohibit salt intrusion at the inland fresh water area. To meet this purpose discharge through the gates have been done at the period of maximum water level difference between inner river and sea level. This discharged water may cause the changes of current pattern and other environmental influences in the vicinity and inner area of semi-closed Mokpo harbor. In this study ADI method is applied to the governing equation for the analysis of the changes on current pattern due to discharged water. As the results of this study it is known that the discharging operation causes many changes including the increase of current velocity at the front water area at piers approaching passage and anchorages. Discussion made on the point of problems such as restricted maneuverability and the safety of morred vessels at pier and anchorage. To minimize this influence the linked gate operation discharging warning system and laternative mooring system are recommended.
        637.
        1999.04 KCI 등재 서비스 종료(열람 제한)
        The extent of heavy metal pollution in agricultural soils near the abandoned mine land site was investigated using their concentrations from the 47 sampling sites in B mine. Samples were prepared using 0.1N HCl -Korean Standard Methods- and then analysed for Cd, Cu, Pb, As and Cr by Inductively Coupled Plasma Spectrometer. In addition, soil and mine tailing samples were sequentially extracted to investigate the chemical speciation of heavy metals in them. The soils in the vicinity of mining area are highly contaminated by heavy metals ranging up to 5.96㎎ Cd/㎏, 253.3㎎ Cu/㎏, 76.7㎎ Pb/㎏, and 15.45㎎ As/㎏, according to the analysis of Korean Standard Methods. The heavy metal levels by the sequential extraction are much higher than its level by Korean Standard Methods, and little correlated with each other. Based on the results, it is suggested that the As pollution in agricultural soils near the AMLS should be dealt as of prior significance in establishing reclamation strategies for the area.
        638.
        1998.10 KCI 등재 서비스 종료(열람 제한)
        Pyrite contained in wasted ore dumps induces a strong acid environment when it contacts oxygenated rainfall. Present research was designed to evaluate the pollution of an area that is supposedly contaminated by pyrite of ore wasted dumps form in Chonju Il Mine. Measured are the pH and selected heavy metal elements in the supposedly polluted hydrologic system. The samples include three types those collected from the stream waters; those from the stream sediments; and those from the rice field soil scattered over the area. The dispersion path of the pollution source was also traced. The pH of the hydrologic system ranged from 3.44 to 5.46, which clearly indicates that the area is on the acid environment. The pH tends to rise as the distance from the minehead increases. The content of heavy metal elements dissolved in the stream water varies as follows; Mn=69.73∼1.99ppm, Cd=0.02∼0.03ppm, Zn=0.77∼1.18ppm, Cu=0.04∼0.13ppm, Pb=0.22∼0.32ppm. The stream water in this state may induce serious heavy metal pollution to the agricultural land and the water for human life especially in the villages down the stream. The content of heavy metal elements dissolved in the stream sediment varies as follows; Mn=245.0∼4685.0ppm, Cd=10.0∼15.0ppm, Zn=105.0∼210.0ppm, Cu=65.0∼155.0ppm, Pb=90.0∼150.0ppm. The content of heavy metal elements dissolved in the rice field soil varies as follows; Mn=185.0∼260.0ppm, Cd=10.0∼15.0ppm, Zn=135.0∼180.0ppm, Cu=65.0∼90.0ppm, Pb=100.0∼130.0ppm. The pollution index in the stream sediment and the rice field soil is 1.36∼2.03, which shows that pollution had already begun all over the area where the samples were collected.
        639.
        1998.10 KCI 등재 서비스 종료(열람 제한)
        지하저장공동의 적절한 설계와관리를 위해서는 공동주위의 지하수 흐름이 분석되어야 한다. 지하수 흐름은 수리전도도의 공간적인 변동성에 의해 영향을 받게 되므로 본 연구에서는 이러한 영향분석을 위해 추계학적 개념을 도입한 2차원 유한요소모형을 개발하였다. 추계학적으로 정의된 불균일 매질에서의 2차원 정류흐름에 대한 근사해를 얻기 위해 Monte carlo 방법을 이용하엿으며, 이를 위해 알려진 평균과 표준편차를 가진 수리전도도를 발생시켰다. 모형을 통한 예측
        640.
        1998.08 KCI 등재 서비스 종료(열람 제한)
        This study estimate the degree of contamination in the streamwater around the Sudokwon landfill site. It was sampled at 10 sites in Jan., Apr., Jul. and Oct., 1996. There were analyzed five kinds of toxic chemical material-CN, ABS, PCB, As, Org-P, and four kinds of heavy metal-Pb, Hg, Cd, C_r^+6. The result are 1)The COD was generally increased to compare before landfill, 2)The Org-P and PCB were not detected at all points, 3)The concentrations of Pb, C_r^+6 and As were lower than the environmental criteria values, 4)The CN, Hg and Cd were over envirommental criteria values, and so emergent regulation is needed, 5)The effects of the streamwater contamination were not only the leachate of the landfill, but also the small factories and agricultural land around the landfill.
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