• Title/Summary/Keyword: East Lake

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Simulation analysis on the separation characteristics and motion behavior of particles in a hydrocyclone

  • Xu, Yanxia;Tang, Bo;Song, Xingfu;Sun, Ze;Yu, Jianguo
    • Korean Journal of Chemical Engineering
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    • v.35 no.12
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    • pp.2355-2364
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    • 2018
  • We evaluated the effect of particle size and associated dynamics on a hydrocyclone separation process in order to understand the movement of the particle trajectories inside the hydrocyclone via numerical analysis, with particles of acid hydrolysis residues discharged in $TiO_2$ production via the sulfate method as a case study. The values obtained from the numerical simulation were successfully compared with those from experimental tests in the literature, allowing a description of the dynamics of the particles, their acting forces, and their relevant properties together with separation efficiency. The results showed that particle motion is jointly controlled by the drag force, the pressure gradient force and the centrifugal force. With increasing particle size, the influence of the drag force is weakened, whereas that of the centrifugal force and pressure gradient is strengthened. Factors including particle density, slurry viscosity, and inlet slurry flow rate also contribute to a clear and useful understanding of particle motion behavior in the hydrocyclone as a method for improving the separation efficiency.

A Study on the Historical and Cultural Landscape of Han River - Around East Lake of Kyung River in Joseon Dynasty - (한강(漢江)의 역사문화경관 연구 - 조선시대 경강(京江) 동호(東湖)지역(地域)을 대상으로 -)

  • Kim, Sun-Hwa;Lee, Jae-Keun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.32 no.2
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    • pp.55-67
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    • 2014
  • The historic cultural landscape of East lake in Kyung river area during Joseon dynasty was very outstanding that it had many attractions of scenic beauty, however, the Han river of today is being recognized as a natural landscape and as a place with low cultural and historical traits. This study applied landscape characteristics of the cultural space of Joseon Dynasty on visual image elements of Lynch to research the landscape characteristics. The research results are as follows. When East lake was applied to visual image elements, it was recognized as a 'superb' 'paths,' and the 'edge' which signifies the boundary showed its 'superb' clarity of the East lake. For the 'node,' a turning point of direction, Dumopo represented the 'superb' awareness. As East lake, Apgujung, and Jecheonjung represented the 'superb' awareness when 'landmark' among visual image elements of Lynch was applied to the cultural space, the awareness level and reputation were proportional to the visual image elements. When pattern, structure, and meaning of the cultural space were clear and had definite identity, the 'landmark' and 'district' elements were 'superb.' It was also identified that when awareness level of space was higher, the awareness of historic cultural landscape was high as well. Therefore, considering visual awareness level of the historic cultural landscape of Han river during restoration to investigate and to conduct case studies is considered to increase the awareness level of historicity and cultural character as well as restoration of the place.

An Analysis on the First Flush Phenomenon by Stormwater Runoff in Eutrophic Lake Watershed (부영양상태 호수유역의 강우유출수에 의한 초기세척효과 분석)

  • Cho, Jae-Heon;Seo, Hyung-Jun
    • Journal of Environmental Impact Assessment
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    • v.16 no.5
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    • pp.341-350
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    • 2007
  • Lake Youngrang is a lagoon whose effluent flows into the East Sea. Because two resort towns and two golf courses are situated at the lake basin, many tourists visit this area. Stormwater runoff surveys were carried out for the eight storm events from 2004 to 2005 in the eutrophic lake watershed to give a basic data for the diffuse pollution control of the lake. Dimensionless mass-volume curves indicating the distribution of pollutant mass vs. volume were used to analyze the first flush phenomenon. The mass-volume curves were fitted with a power function and polynomial equation curves. The regression analysis showed that the polynomial equation curves were better than the power function in representing the tendency of the first flush, and second degree polynomial equation curves indicated the strength of the first flush effectively.

Structure and Dynamics of Phytoplankton Commnities in Uiam Lake, Korea (의암호의 식물성 Plankton 군집의 구조와 동태)

  • Yim, Yang-Jai;Kyu Song Cho;Chang Nam Sin
    • The Korean Journal of Ecology
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    • v.5 no.2_3
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    • pp.132-135
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    • 1982
  • Structure and dynamics of the phytoplankton communities of Uiam lake, Korea, was investigated. In the Uiam lake four dominant species were found Oscillatoria limosa at Chuncheon City side, O. tenuis at Soyang river side, Melosira italica at south-east side and Asterionella gracillima at west side of the lake. By cluster analysis, based on the similarity index and dissimilarity index, the phytoplanktons in this lake were grouped into three communities; i.e. Oscillatoria, Melosira and Asterionella community. And also the same groups obtained by the cluster analysis were recognized by polar ordination technique along polluted degree gradient. It is clear that oscillatoria community occur in polluted site, Asterionella community in unpolluted site and Melosira community in less polluted site.

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Survey of Antibiotic Resistant Bacteria in Lake Gyeongpo, Korea (경포호의 항생제 내성 세균 조사)

  • Dukki Han
    • Korean Journal of Environmental Agriculture
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    • v.42 no.3
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    • pp.169-176
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    • 2023
  • The emergence and spread of antibiotic-resistant bacteria have been increasing with anthropogenic contamination. Understanding the prevalence and distribution of these resistant bacteria in environments is crucial for effectively managing anthropogenic pollutants. Lake Gyeongpo in the Gangwon Province of South Korea is known for its diverse ecological features and human interactions. The lake is exposed to pollutants from nonpoint sources, including urban areas, agricultural practices, and recreational activities, which can introduce antibiotics and foster antibiotic resistance in bacteria. The present study investigates Lake Gyeongpo as a potential reservoir for antibiotic-resistant bacteria in a natural ecosystem. A total of 203 bacterial isolates were collected from six sampling locations in Lake Gyeongpo during May, July, and November 2022. Most isolates were taxonomically identified as Pseudoalteromonas, Bacillus, Shewanella, and Vibrio spp.; their abundance showed a spatiotemporal distribution. An antibiotic susceptibility test was conducted on 75 isolates using the disk diffusion method with six drugs according to the CLSI guideline; 42 isolates were resistant to one or more antibiotics. Among these, 15 isolates were identified as multidrug resistant bacteria. This finding suggests the potential anthropogenic impact on Lake Gyeongpo and provides valuable insights into the dissemination of antibiotic resistance caused by anthropogenic pollutants.

Overview of the Fisheries and Aquaculture Resources in the Democratic Republic of Congo

  • Ekoma, Christian Ngunda;Mangala, Rapael Bukura
    • Journal of Marine Bioscience and Biotechnology
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    • v.3 no.1
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    • pp.13-17
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    • 2008
  • The Congo has a maritime coastline of 40 km, covering an area of $2,345,409km^2$. The fluvial system covers around $34,000km^2$ in a network of more than 33,000 km of rivers, principal tributaries, and streams. There are around 1,000 known species of fish, essentially freshwater and some brackish. The lakes of the Rift Valley contain the richest lacustrine fauna in the world. The family of Cichlidae alone has more than 900 species. At the same time, the lakes are profoundly different. Lake Tanganyika has 250 species of fish, of which 216 are endemic, whereas Lake Kivu contains only 32 and 16, respectively. A dense hydrographic network of water surfaces, inundated plains and lakes cover around $86,080km^2$ (3.5% of the national area) and have a considerable aquatic potential. The large peripheral lakes of the East cover around $48,000km^2$ of which 47% are under Congolese jurisdiction. The respective areas belonging to the Congo are: Lake Tanganyika, $14,800km^2$; Lake Albert, $2,420km^2$; Lake Kivu, $1,700km^2$; Lake Edward, $1,630km^2$; Lake Mo$\ddot{e}$ro, $1,950km^2$. Another two important lakes in the interior, Lake Tumba and Lake Mai-Ndombe, cover (between them) 2,300 and $7,000km^2$, depending on season (less in the dry season and more in the rainy season). There are also the lakes of the Kamalondo depression ($6,256km^2$), Lake Tshangalele ($446km^2$) and Lake N'Zilo ($280km^2$).

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Analysis on the evolution of water resources situation in Qiandao Lake Basin from 1960 to 2020

  • DU Junkai;Qiu Yaqin
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.27-27
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    • 2023
  • To analyze the evolution of water resources in Qiandao Lake Basin under the condition of climate change, a WEP-L distributed hydrological model was established to simulate the water cycle process in the basin during 1960-2020. The Mann-Kendall non-parametric test method and Hurst index method were used to analyze the inter-annual variation and annual distribution characteristics of the total water resources in the basin. The multi-scale temporal and spatial distribution and evolution trend of water resources in Qiandao Lake Basin were evaluated. The results show that: (1) The WEP-L model has good simulation results in the Qiandao Lake basin, and the Nash coefficient rate is above 0.83 in the periodic period and above 0.85 in the verification period. (2) The water yield coefficient of the whole basin ranges from 0.436 to 0.630. The annual average total water resource is 12.25 billion m3, equivalent to 1176.4mm of water depth. The annual distribution process shows a unimodal structure, and the water depth of each sub-basin ranges from 742 mm to 1266 mm, and the spatial distribution is higher in the west and lower in the east. (3) The annual water resources series in the basin showed an insignificant upward trend, and the Hurst index was 0.86, indicating a continuous upward trend. From the perspective of monthly water resources, January and February increased significantly, the other months were not significant changes.

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Topographic characteristics of Yeonho lake, Uljin-gun, Gyeongsangbuk-do (경북 울진 연호(蓮湖)의 지형적 특성)

  • Woo, Seung-Hyun
    • Journal of the Korean association of regional geographers
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    • v.22 no.1
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    • pp.211-224
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    • 2016
  • Natural lakes are estimated in variety with that's function or value depending on age environment or geographical characteristics. There are many kind of natural lakes, but the kind of natural lake is limited in rivers in korea flowing into East Sea. However, Yeonho lake in Uljin has different geographical characteristics with oxbow lake or lagoon which is common in korea's river flowing into East Sea. Therefore the purpose of this study is to analyze geographical characteristics due to the process of Yeonho's formation. Further more research for protecting wetland is needed to adequately preserve, depending on the geomorpologic process. To analyze geographical characteristics, it was essential to compare and analyze topographical map of 1918 1956 2012 and I pictured estinated line of bedrock and longitudinal section of Nam-dae cheon(Riv) Yeonho cheon(Riv). In addition, I denoted flooded areas through design flood level of Nam-dae cheon(Riv) Yeonho cheon(Riv) and analyzed particle size distribution of deposited sediment due to consider deposit environment. The results of study are as follows. In conclusion, Yeonho lake is floodbasin which was not researched at river flowing into East Sea. Through this study, my opinion is that floodbasin can be formed in the river that is steep and short. I argue that preservation methods will be seeked by geomorphologic process of floodbasin and development of downtown.

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The Spatial-temporal Changes of the Land use/cover in the Dongting lake Area of Central China during the Last Decade

  • Rendong, Li;Hongzhi, Wang;Dafang, Zhuang
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.417-419
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    • 2003
  • Based on the Chinese resource and environment database, and using the Landsat TM and ETM data acquired in 1990 and 2000 respectively, the spatial-temporal characteristics of land use/cover changes in the Dongting lake area of central China was analyzed. The result showed that cultivated land decreased by 0.57% of total cultivated land. Built -up land and water area expanded, with an increase of 8.97% and 0.43% respectively. 94 percent of the cropland decreased was changed into water (mostly to fishpond) and built-up areas. Land-use changed most quickly in cities, and the slowest in the north and east of the study area.

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Distribution of Methyl Mercury in Sediments from Kyeonggi Bay, Namyang Bay, Chinhae Bay, and Lake Shihwa, Korea

  • Lee, Kyu-Tae;Kannan, Kurunthachalam;Shim, Won-Joon;Koh, Chul-Hwan
    • Journal of the korean society of oceanography
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    • v.33 no.4
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    • pp.178-184
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    • 1998
  • To elucidate contamination levels and distribution of methyl mercury (Me-Hg) in Korean coastal areas, 126 sediment samples were collected from Kyeonggi Bay, Namyang Bay, Chinhae Bay, and Lake Shihwa during 1995-1996, and the Me-Hg concentrations were determined by cold vapor atomic fluorescence spectrometry (CVAFS). Contamination levels of Me-Hg in sediments from Kyeonggi Bay, Namyang Bay, Chinhae Bay, and Lake Shihwa were 274 ${\pm}$ 990, 108 ${\pm}$ 24, 294 ${\pm}$ 342, and 1080 ${\pm}$ 760 pg/g, respectively. Concentrations of Me-Hg in sediments were significantly correlated with total organic carbon and sulfur contents, but were independent of mud contents and mean grain size. The highest concentration of Me-Hg (7100 pg/g) was observed at Incheon North Harbor (Site Kl9) in Kyeonggi Bay. This Me-Hg concentration was one or two orders of magnitude higher than those in other Kyeonggi Bay sediments were. The average concentration of Me-Hg in sediments from Lake Shihwa was higher than in those from other study areas. The three peaks of Me-Hg concentrations were observed on three sites (55, 56,and 510) in Lake Shihwa and gradually decreased in distance-dependent manner around these sites. High concentrations of Me-Hg at surface and 10-cm sediment depth in Chinhae Bay maybe due to higher rates of methylation process by active sulfate-reducing bacteria or higher concentrations of total mercury available to sulfate-reducing bacteria.

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