• Title/Summary/Keyword: Sam-Cheong

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Deposition Characteristics of the Sandbar and Estimation of the Mass Transport Flux in the Nakdong Estuary (낙동강 하구역의 사주 퇴적특성과 물질수송플럭스 산정)

  • YOON RAN-SAM;LEE IN-CHEOL;Ryu CHEONG-RO
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.05a
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    • pp.131-137
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    • 2004
  • This paper is intended as an investigation of the deposition characteristics and mass transport flux estimation in the Nakdong estuary. In order to understand the effects of the tidal current circulation which influenced to an estuary terrain change, the seawater circulation calculation by the use of 2D numerical model for the three cases of without riverflow, mean and flood riverflow quantity condition practiced and each sectional net-flux of water quantity between sandbars(so called, dung) estimated. It may be that an estuary terrain change due to the large scale construction and reclamation at the Nakdong estuary influence to the long-time deposition characteristics. by the revim for the old research, we know that the development of the local sandbars has been moved toward the east-side from the west-side estuary area after the construction of the Nakdong river dike, at present the strong-acted location is the Bakhap-dung of the front sea of Tadea. The seawater circulation pattern at this large scale area of tidal flat bring on a change due to the water quantity outflowing from the Nakdong river. Base on the calculated results for the section net-flux of water quantity, we see that the accumulating action very strong at the local sea around Jangjado, Bakhapdung and Tadae for the case of flood riverflow quantity condition, but at the local sea around Jinudo for the another cases. Consequently, it is emphasized that in the Nakdong estuary the main sensitive regions which influenced from the discharge of riverflow were the local sea around Jangjado, Bakhapdung, Tadae and Jinudo.

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A Study on the Distribution and Composition of Plastic Debris in the Coastal Beaches of Young-Il Bay (영일만 주변 해수욕장의 미소 플라스틱 분포와 조성에 관한 연구)

  • Kim, Sam-Kon;Kim, Jong-Hwa;Kim, Min-Seok;Cheong, Sun-Beom;Lee, Jung-Tae
    • Journal of Fisheries and Marine Sciences Education
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    • v.12 no.2
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    • pp.152-163
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    • 2000
  • Floating resin pellets including plastics were surveyed from 7 coastal beaches near Young-il Bay during summer and winter season on 1998 ~ 2000 year. Plastic fabrication materials in the survey were founded with 6 items using the following; resin pellets, plastic debris, styrofoams, cigar filters, wood pieces and charcoals. The results deduced in the areas are as follows: 1. The seasonal variability of the all debris is revealed that summer season were remarkably larger than those of winter. This is deduced it is attributed to meteorological effects, e.g, the seasonal wind strength, current vectors and resorts of crowded people for beach enjoy. And the distribution of plastic debris is Pohang Songdo $12.9ea/m^2$, Pohang Bookbu $8.8ea/m^2$, Togoo $4.9ea/m^2$, Chilpo $3.2ea/m^2$, Hwajin $1.4ea/m^2$, Wolpo and Guryongpo $0.8ea/m^2$ respectively. 2. Compared with each beaches, Songdo beach, northern part beach of Pohang city and Togoo beach have higher densities than those of the others. Especially, the highest densities of all debris were discovered in the Songdo beach of Pohang city. 3. The change of density over the whole year was similarly distributed in quantities and fabrication materials. 4. These surveys were founded that the most parts of plastic debris materials were made up with PE and PP.

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Spatial and Temporal Variation Characteristics between Water Quality and Pollutant Loads of Yeong-il Bay (II) - Mutual Variation between Inflowing Pollutant Loads and Water Quality - (영일만 유입오염부하량과 수질의 시${\cdot}$공간적 변동특성(II) - 유입오염부하량과 수질의 상호거동 -)

  • YOON HAN-SAM;LEE IN-CHEOL;RYU CHEONG-RO
    • Journal of Ocean Engineering and Technology
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    • v.17 no.5 s.54
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    • pp.32-38
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    • 2003
  • This study investigates the distribution characteristics and relationship of water quality, and analyzes the spatial and temporal variation and distribution of the pollutant loads at Yeong-il Bay. The results of these analysis, the concentrations of nutrient loads (T-N and T-P), both appeared to be at the maximum value in November, while most small values were taken in May for the T-N, and in August for the T-P. For COD, the maximum concentration was in August, which has much precipitation during the same season, T-N was at the mean, and T-P was at the minimum value. Using the cluster analysis to develop the division of the sea basin by the dendrogram, before and after construction of Pohang New-port, the variation characteristics of water quality of Yeong-il Bay were discussed. The in flowing pollutant loads were transported to the landward by the high-density salinity water volume of the bottom layer therefore, it formed nutrient trap or coastal trapping areas of the pollutant load. By this mechanism, it is clear that the water volume with high-density nutrient exists on both sides of the Pohang New-port. Thus, the sea basins increasing concentration of the pollutant load at Yeong-il Bay are most prevalent at Hyeong-san estuary, the Pohang Old, and New-port. To improve water quality of this sea basin, the reduction of these nutrients loads should be the highest priority.

Experimental study on transmission and stability of submerged breakwater (잠제의 전달율과 안정성에 관한 실험적 연구)

  • Kim, Yong-Woo;Yoon, Han-Sam;Kim, Hong-Jin;Ryu, Cheong-Ro;Sohn, Byung-Kyu
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.10a
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    • pp.213-219
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    • 2003
  • As the 2-D hydraulic experimental results for the submerged rubble-mound structure, we have concerned with their stability/function characteristics of structures by the effects of wave force, scour/deposition at the toe and wave transmission ratio at the lee-side sea. And as to investigate the variation characteristics of wave transmission ratio which depended to a geometrical structure of the submerged breakwater profiles, the critical conditions for the depth of submergence and crest width obviously presented. In summary, there results lead us to the conclusions that the wave control capabilities of submerged breakwaters by the variation of the submergence depth is high about 4 time degrees at the efficiency than the that of crest width. The destruction of covering block at the crest generated at the region which located between maximum damage curve, it maximum damage/failure station from the toe of the structure were 0.2L. As the wave transmission coefficient and the slope of the structure increase, the damage/failure ratio and the maximum scour depth at the toe was extended, respectively. When maximum scour depth happened. The destruction of covering block which located at the toe generated at the front slope destruction. Finally, it was found from the results that the optimization of structure may be obtained by the efficiently decision of the submergence depth and crest width in the permissible range of wave transmission ratio.

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An Experimental Study on Annulus Muffler of Automobile (자동차용 환상형 소음기에 관한 실험적 연구)

  • Kim, Byoung-Sam;Song, Kyu-Keun;Sim, Sang-Cherl;Cheong, Byeong-Kuk
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.217-222
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    • 2006
  • Internal combustion engine is the main source of environmental pollutants and therefore advanced technology is required to reduce harmful elements from the exhaust gases all over the world. Especially, when the exhaust gas is released front the automotive muffler, exhaust noise has many bad influence on the surrounding environment. In order to reduce the exhaust noise, it is necessary that automotive muffler must be designed for best exhaust efficiency. The sound insulation room was installed for the analysis of an acoustics characteristics of the noise from automotive muffler, in this study. Exhaust gas noise, noise distribution characteristics, pressure and temperature of exhaust gas were investigated with the change of annulus temperature of air cooled annulus automotive muffler and cooled annulus automotive muffler. The following results were obtained with this study. From the frequency analysis of automotive muffler, high noise distribution was observed in the range $100{\sim}2000Hz$. It means that the noise in this range has an dominate influence for the overall noise. Noise reduction of automotive muffler was affected by the temperature of annulus. It is caused the result that the high temperature and pressure of exhaust gas are changed lower by the drop of annulus temperature. The tendencies of noise, the temperature and pressure of exhaust gas are similar to the performance curve of engine. Exhaust gas pressure is determined by the r.p.m. of engine and affected by the cooling performance of automotive muffler.

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Delta Development in the Nakdong River Estuary: a Literature Survey (낙동강 하구역 삼각주 발달에 관한 문헌 고찰 연구)

  • Yoon, Han-Sam;Yoo, Chang-Ill;Kang, Yoon-Koo;Ryu, Cheong-Ro
    • Journal of Ocean Engineering and Technology
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    • v.21 no.2 s.75
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    • pp.22-34
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    • 2007
  • We present basic data for developing new research topics and closely examine the existing data on the development and organization of the Nakdong River Estuary Delta by analyzing various studies of the area, including ocean engineering, coastal engineering, ocean environmental engineering, geomorphological, and geological studies. We first defined the general concepts related to the estuary and delta and reviewed the historical development of the Nakdong River Estuary Delta over the past 100 years. We then examined the origin and core elements of the estuary deposits that constitute the delta. In addition, we scrutinized the main factors affecting the development of the delta and analyzed existing research on delta development mechanisms by core researchers. The construction of an estuary barrage is one of the main factors effecting estuarine circulation and has altered the physical oceanic environment, area of deposition, atmospheric environment, and vegetation community of the delta. These factors affect the estuary circulation in turn, altering the delta. Along the Nakdong River, an unsteady-state sandy barrier appears at approximately three times the distance of the wavelength of incident offshore waves, and this terrain forms approximately 10-15 years after reclamation in the interdistributary upper stream and transforms the shoreline. It is necessary to develop a technique to predict terrain change that reproduces the erosion and accumulation of estuarine deposits. To determine the parameters and variables necessary to reproduce this system, continuous on-site monitoring is necessary. The existing research did not fully examine the terrain changes in Nakdong River Estuary or the periodic developmental characteristics. To understand the future process of estuary delta development, it is necessary to establish an integrated management system.

A comparison of lytic activity of swine and chicken phages with Staphylococcus hyicus of swine, chicken and cattle origin (돼지, 닭 및 소유래 Staphylococcus hyicus에 대한 swine phage와 chicken phage의 용균능 비교)

  • Park, Cheong-Kyu;Jang, Han-Nae;Kwon, Young-Sam
    • Korean Journal of Veterinary Research
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    • v.43 no.1
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    • pp.87-94
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    • 2003
  • The lytic activity of the set of swine and chicken phages which were derived from lysogenic Staphylococcus hyicus strains of swine and chicken origin was compared by means of S. hyicus isolated from swine, chicken and cattle. Of the 80 strains each from swine and chicken, 71 (88.8%) of strains from swine and all the strains of chicken origin were found to be lysogenic. Swine phages showed wider range of lytic activity to the examined strains than that of chicken phages. Using chicken phages at $100{\times}routine$ test dilution (RTD), 25.0%, 85.6% and 50.0% of swine, chicken and bovine strains were lysed, respectively. However, when the set of swine phages was used at $100{\times}RTD$, higher frequency of the typable strains was found in strains of swine and chicken origin (73.8% and 90.2%). Phage F12 and L16 from chicken set were found to be highly active with chicken and bovine strains. On the contrary, all the swine strains were completely resistant to lysis by the two phages at $100{\times}RTD$. Thirteen (12.5%) of 104 S. aureus strains, 1 (1.8%) of 55 S. simudance strains, 31 (58.5%) of 53 S. chromo genes strains, and none of 31 strains of other coagulase-negative Staphylococcus species isolated from bovine mastitis were typable with the set of swine phages.

A study on the growth behavior of nano NiO crystals synthesized by a solid state reaction (고상반응에 의한 NiO 나노 결정의 성장거동에 관한 연구)

  • Kim, Chang-Sam;Cheong, Deock-Soo;Kang, Seung-Min
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.19 no.4
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    • pp.184-189
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    • 2009
  • We characterized the growth behavior of nano NiO crystals synthesized by heat-treatment in air at the elevated temperatures using nickel nitrate ($Ni(NO_3)_2{\cdot}6H_2O$). The crystals had the octahedral shape and the length of 200${\sim}$500 nm. The truncation was observed when the NiO powder was heated up to $900^{\circ}C$ for 2 hours. but not be seen at under $600^{\circ}C$. It was observed that nano NiO crystals synthesized at $900^{\circ}C$ made up the networks, the coalescence of the nano crystals through the neck formation between the crystals appeared as the first stage in the sintering mechanism.

Spatiotemporal Changes of the Sand Barrier using Marine Charts Analysis in the Nakdong River Estuarine (해도분석을 통한 낙동강 하구 사주 면적의 시.공간 변화)

  • Yoo, Chang-Ill;Yoon, Han-Sam;Ryu, Cheong-Ro;Lee, In-Cheol
    • Journal of Ocean Engineering and Technology
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    • v.20 no.6 s.73
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    • pp.54-60
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    • 2006
  • This study discusses characteristic of spatiotemporal changes of the sand barrier in the Nakdong estuarine for the last century, focusing on geomarphologic evolution and mobility of sand barriers in the view of coastal engineering. The Nakdong estuarine, the research subject, has a complexly changing natural environment by interaction between ground and marine elements such as ocean wave, tidal current, sediment, etc. Moreover, recently, unnatural geomorphologic changes (e.g., seaside reclamation, new harbor construction, etc.) has been radically increased in this area with increasing desire for coastal development. Because of this, its sand barrier has developed quite unstable condition. Therefore, to identify the development process of geomorphologic changes in this area, required is a close examination on historical characteristics of spatiotemporal changes of the sand barrier in relation to surrounding seaside reclamation and physical environmental changes. This study, based on the marine charts published in between 1927 and 1995 year, analyzes the length and area of the sand barrier for the last hundred years, and investigates the cause of the changes by looking into the change of water depth for the last two years and doing ocean-physical site observations. In conclusion, the sand barrier of the Nakdong estuarine expands toward the open sea by $7.4{\sim}26m$ in annual average, maintaining a fixed distance of $1,241{\sim}1.279m$, and its area is expected to increase about $2.8km^2$ annually. This is characterized by the wocean wave from the open sea and the discharge of Nakdong River.

The Value of Comparison with Four Dimension Time Resolved Imaging of Contrast Kinetics(TRICKS) MRA by Time of Flight(TOF) MRA (4차원 TRICKS 자기공명혈관조영술과 기존 TOF 자기공명혈관조영술의 비교 및 유용성)

  • Bae, Sung-Jin;Lim, Cheong-Hwan;Park, Byung-Rae;Shin, Woon-Jae;Kim, Jung-Sam
    • The Journal of the Korea Contents Association
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    • v.10 no.3
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    • pp.215-221
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    • 2010
  • To assess the clinical value of time resolved imaging of contrast kinetics(TRICKS) MRA by comparison with conventional time of flight(TOF) MR angiography. Both TOF-MRA and TRICKS-MRA were performed in 17 patients with cerebrovascular disease and in 6 patients with brain tumor. Among 17 cerebraovascular patients, digital subtraction angiography(DSA) data were also obtained in 11 patients. TOF-MRA showed good spatial resolution but short in temporal resolution. Although TRICKS-MRA showed somewhat low spatial resolution, it showed superior temporal resolution by distinguishing vessel and tumor in all patients. Also, from the analysis of vessel-tumor relationship, TRICKS-MRA showed better performance than TOF-MRA. TRICKS-MRA makes it possible to image arterial, capillary and venous phase sequentially with very speedy manner and therefore, the clinical use of this method is highly suggestive for future use.