• 한국환경보건학회지
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• 제26권4호
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• pp.1-8
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• 2000

The objective of this study was to identify the sources and to estimate the source contributions to the atmospheric TSP(total suspended particulate matter) and PM-10(particulate matter with aerodynamic diameters less than 10$\mu\textrm{m}$) concentration in Taegu area. A total of 84 samples was collected during the January to December 1999. TSP and PM-10 were collected on filters by portable air sampler, and heavy metals in TSP and PM-배 were analyzed by ICO(Inductively Coupled Plasma Spectrometery) after preliminary treatment. The results were follow as : First, annual average of TSP and PM-10 concentration was 123 and 69$\mu\textrm{g}$/㎥ respectively. The concentration of TSP and PM-10 were highest in winter season compared to other seasons. Second, the concentration of Al, Fe, Mn were higher in TSP than in PM-10, indicating that these heavy metals are generally associate with natural contributions. Third, metal combinations showed that a high correlation among concentrations of heavy metals were follows: As Al, Fe and Mn in TSP ; Ni, Cr, Cd and Pb in PM-10. Finally, Statistical analysis was performed using Principal Components Analysis(PCA) in order to find possible sources of the pollutants. The factor analysis was permitted to identify four major sources(soil/road dust resuspension, waste incineration, furl combustion, vehicular emission) in each fraction. These source accounted for at least 83, 85% of variance of TSP and PM-10 concentration in Taegu area.

• 한국해안해양공학회지
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• 제3권1호
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• pp.38-44
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• 1991

간단한 box 모형이 장방형 해분에서의 세립 퇴적물의 퇴적현상을 설명하기 위하여 이용되었으며. 이 모형에 필요한 침식 및 퇴적률의 계수를 조사하여 남해안 가막양만에 적용하여 보았다. 해분이 외해와 연결되어 있고 외해의 부유퇴적물 농도가 일정하면 해분내에서 한 조석 주기 동안의 평균 부유퇴적물 농도는 일정한 값을 유지하게 되고 조류의 게류시 부근에는 퇴적이 일어나고 최대 유속시 부근에는 바닥 퇴적물의 재부유 및 침식이 일어나는 것을 보여주고 있다. 가막양만 처럼 퇴적이 우세한 해분에서는 조석 주기 중 퇴적이 일어나는 시간과 최대 퇴적률이 침식에 비하여 크게 나타나고 있으며, 이러한 퇴적 우세 해분의 부유퇴적물 평균농도는 외해의 부유퇴적물 농도보다 낮은 값을 보이고 있다. 또한. 조류의 유속변화에 따른 해분내기 부유퇴적물 농도변화는 고조의 약 한 시간 전에 최대값을 나타내고 저조의 약 한 시간 후에 최소값을 나타낸다.

• 한국수자원학회논문집
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• 제40권5호
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• pp.409-418
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• 2007

건기에 합류식 관거 내에 퇴적된 고형물은 우기에 재부상하여 초기부하(first-flush) 현상의 주된 원인이 되고 있으며, 이러한 고형물의 퇴적으로 인해 관거 내 통수능이 감소하여 도시지역의 국지적인 내수침수가 발생하고 있다. 이와 같은 문제를 해결하기 위해서는 장기간에 걸친 관거 내 고형물 퇴적량을 관측할 필요가 있으나 많은 비용과 노력이 수반되어야 한다. 본 논문에서는 MOUSE 모형에 의해 산정된 결과로부터 고형물 퇴적량을 산정하기 위한 회귀식의 개발 및 적용성을 검토하였다. 분석 결과 관거 내 퇴적고형물의 관측 자료가 구비되어 있지 않아 실질적으로 비교하기는 곤란하지만 MOUSE 모형이나 EPA(미환경보호청)에서 제시한 공식을 이용하여 산정한 결과와 비교해 볼 때 본 연구에서 개발된 산정식은 적용성이 있음을 보여주고 있다.

• 한국대기환경학회지
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• 제14권3호
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• pp.163-176
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• 1998

In this study, airborne particle samples were obtained to determine the concentrations of particulate air pollutants in indoor and outdoor air of public facilities in Taegu area. Total of 12 public facilities, regulated by the Public Sanitary Law, were selected as sampling sites, which include three underground arcades, one railway and two bus terminals, three general hospitals, and three department stores. In each place, sampling was carried out seasonally during the period of October 1994 to July 1995, and four samples per each site per season were collected both indoors and outdoors simultaneously. After determination of suspended particulate matter (SPM) mass concentrations, the particle samples were divided into two parts for subsequent chemical analysis: one for the analysis of trace elements and the other for water soluble ions. Seasonal levels of SPM appeared to be the highest in spring and the lowest in summer both indoors and outdoors, while locational variations of highest in statioyterminals, and lowest in department stores . SPM concentrations indoors and outdoors did not show any significant differences each other in most places . However, there were significant correlations between indoor and outdoor levels of SPM and other chemical species . These results indicates that indoor SPM levels are likely to be significantly affected by outdoor sources in many places. The most significant source of SPM was estimated to be the resuspension of soil/road dust both indoors and outdoors . The concentrations of toxic heavy metals (Pb, Cd, Cr, Cu) in underground arcades appeared to be very much lower than the established air quality guidelines for underground environments. In addition, it is likely that micro-environmental parameters such as temperature, humidity, and air velocity, play a less significant role than outdoor air quality as a factor affecting the levels of particulate pollutants in indoor environments of public facilities in Taegu area.

• 한국환경복원기술학회지
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• 제4권4호
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• pp.56-63
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• 2001

This paper presents treatment efficiency and plant growth of a subsurface-flow constructed wetland system (23 m in length, 6.5 m in width, 0.65 m in depth) over one year after its establishment on floodplain of a stream in June 2000. An upper layer of 10 cm in depth was filled with course sand and the main biological layer of 50 cm depth with crushed stone with 8 - 15 mm in diameter. The system was planted with common reeds (Phragmites australis) grown on pots. Effluent discharged from a secondary-level treatment plant was funneled into it. Reed stems emerging in April 2001 grew up to 145.9cm until July 2001. The number of reed stems in July 2001 increased by about 11 times compared with that just after planting. The system was inundated seven times by storms over the monitoring period. Reeds were slightly bent after flooding, however they returned to almost upright standing in a couple of weeks. Small portion of inside slope of berm was eroded and the system surface had a sedimentation of 2 - 3 mm in depth. The average removal rates for SS, $BOD_5$, T-N and T-P was 73%, 70%, 53%, and 72%, respectively. The purification efficiencies for SS and $BOD_5$ were fairly good. The reduction rates for T-N was relatively low for the period of late fall through winter until early spring due to lower water temperature which retarded microbial nitrification and denitrification mechanisms. Reduction in the concentration of T-P during fall and winter was relatively higher than that during spring. Leach of phosphorous from plant litters lying on system surface and slight resuspension of precipitated phosphorous in substrates resulted in lower reduction for T-P in spring.

• ALGAE
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• 제19권4호
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• pp.339-347
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• 2004

Seaweed community of the sub tidal rocky habitats along the coast of Geumo Archipelago in the central South Sea of Korea is described. This area is characterized by archipelago in which islets are separated by shallow bottom sediments (primary, muddy sand), and turbidity is generally high due to the resuspension of bottom sediments. The hard substrata available for algal attachment are limited to less than 10 m in depth. Thirty sites were randomly chosen along the coast from August 2003 to September 2003 and a 50 m long transect was established at each site. The transect began at a depth of 1 m and ended at the depth of 9 m. The percent cover of all species other than crustose coralline algae was estimated at 2 m depth intervals along the transect using a 0.25 m$^2$ PVC quadrat with 25 squares. Thirty-six species were identified including 6 Chlorophyta, 10 Phaeophyta and 20 Rhodophyta. Species with more than 5% mean bottom cover were Gelidium amansii, Corallina pilulifera, Amphiroa dilatata and Carpopeltis cornea, which formed dense turf-forming algal assemblages at 1-5 m depth. At all sites except S11-S15 located in the western coast of Sorido, bottom covers of seaweed species at the depth deeper than 7 m were less than 6%. The lower limit of algal assemblages was 9 m in depth. We speculate that the limited water clarity and vertical extent of hard substrata available for the settlement of seaweed species are the direct cause of reducing the diversity, abundance and distributional extent of algal assemblages in the area.

• Journal of Chest Surgery
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• 제21권3호
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• pp.488-496
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• 1988

Thirty-seven patients of aortic aneurysm underwent operations during January 1984 December 1987 at our hospital. Twenty-six patients had aneurysms involving ascending aorta, three patients had aneurysms involving both ascending aorta and abdominal aorta. and eleven patients had aneurysms involving descending thoracic or abdominal aorta. Among the patients who had aneurysms involving ascending aorta, annuloaortic ectasia with aortic regurgitation were thirteen and all of these underwent ascending aorta graft replacement + AVR with composite graft. The patients who had aortic regurgitation due to ascending aortic dissection were three and all of these underwent intraluminal ringed graft insertion at ascending aorta + aortic valve resuspension. Intraluminal ringed graft insertion was safe, simple, and fast method in the operation for aortic aneurysm. Eleven patients were underwent this operation and the results were good. Major causes of death of the patients who underwent aortic aneurysm operation are underlying cardiovascular diseases or delayed rupture of the aneurysm or complications related newly appeared aneurysm. Among our patients, dissection progressions were appeared in two but neither severe nor complicated. And no patient died from delayed rupture of aneurysm or complications related newly appeared aneurysm. All patients were followed up via OPD and were controlled hypertension or heart failure if present. Operative mortality is 18.9\ulcornera in all, 23% in patients who had aneurysms involving ascending aorta and 7.6` who had aneurysms involving descending thoracic or abdominal aorta. Comparing with other reports, our operative mortality is still high but improved steadily. So we recommend aggressive surgical management of the aortic aneurysm.

• Journal of Chest Surgery
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• 제21권3호
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• pp.497-509
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• 1988

Current therapy of aortic dissections remains unstandardized because of the relative rarity of these catastrophic events and conflicting reported results of various therapeutic strategies. Hence, we reviewed our current results and planned to purify our method of interpretation of results and so, to standardize therapeutic managements. This study comprised unselected, consecutive 27 patients with aortic dissections who were operated at Seoul National University Hospital from Jan 1983 to March 1988. The results from analysis of their preoperative, operative and postoperative finding were as follows: 1] 7 patients had acute type A, 14 had chronic type A, 4 had acute type B, and 2 had chronic type B. 2] The causes of dissections were unclear, but 8 patients had Marfan`s syndromes, 2 had previous operative histories on cardiovascular systems and 2 had congenital heart diseases. 3] Multiple preoperative variables were found to correlate significantly with operative mortality and complications. The prevalences of such preoperative major complicating factors were significantly more frequent in acute than chronic [P < 0.05] and type A than type B [P < 0.01]. 4] Operations were performed according to the type of the dissections and whether it was acute or chronic. Usually dacron tube graft replacements were performed[25/26]. Intraluminal sutureless graft replacement was performed in 11 patients. Of the 14 patients with combined aortic regurgitation, concomitant aortic valve resuspension in 4, seperative aortic valve replacement in 1, and aortic valve replacement with coronary reimplantation were performed in 9 patients. 2 patients had concomitant arch vessel managements. 5] Over-all operative mortality rate was 33% and 54% for acute type A, 25% for acute type B, 29% for chronic type A, 0% for chronic type B respectively. The main causes of operative mortality were cardiovascular complications [mainly CPB-weaning failure] in acute cases and hemorrhagic complications in chronic cases.

• 한국농공학회논문집
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• 제47권5호
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• pp.87-97
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• 2005

The field scale experiment was performed to examine the effect of physical design parameters on the constructed wetland performance and recommend the feasible design of constructed wetland in Korean polder areas. Four sets (each set of 0.85 ha) of wetland (0.8 ha) and pond (0.08 ha) systems were used. Two different wetland systems, a wetland-pond system and a pond-wetland system, were studied to examine the effect of wetland and pond configuration. And two different length-to-width ratios were used, 2: 1 and 0.8: 1, to examine the effect of aspect ratio. A pond-wetland system was more preferable than a wetland-pond system, and also requires a smaller area than a wetland-pond system or a wetland system to reduce T-P. There was no difference in effluent concentration between the 2:1 system and the 0.8:1 system. Although the linear velocity of the 2:1 aspect was higher than the 0.8:1 aspect, resuspension was not a factor in this study due to a very low linear velocity. From this study and other literature review, it was found that design method of paddy rice field could be applied and expanded to the design of constructed wetland in Korea. Further investigation for the detailed design parameters of constructed wetland needs be continued for design method of paddy rice to be applied in full scale.

• 한국농공학회논문집
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• 제49권5호
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• pp.57-65
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• 2007

The objective of this study was to evaluate chemical water quality by hourly monitoring(25hr) of Saemangeum esturary. For this study, we selected 2 sites like a Mangyong Bridge(St. 6) and Dongjin Bridge(St. 7). Inflow of salt water was not detected during low tide(maximum 553, 508cm) of all stations, while the salinity rises were detected in spring tide(750cm). When 602m of maximum tide was reached, salinity concentration was increased at St. 7, while there was no change in St. 6. Therefore, We know that salinity variation is greatly influenced by tide height at survey site. Also, significant variance of salinity(p<0.05) was found between St. 6 and St. 7 because dike construction made the flood tide move into the Dongjin river. Total suspened solids(TSS) concentration was increased because of the river runoff at St. 6, and also the turbulance and resuspension according to salt intrusion at St. 7. During the high tide, the water discharge from the sea seemed to dilute the nutrient but to elevate TSS concentration in St. 7. Silicate and nitrate concentrations in the studied site were decreased by the mixing of sea water, whereas the evident trend of phosphate concentration was not found. This result can be explained by the phosphorus condition. Phosphorus exists inactive when it is affected by hydrated iron and adsorbed onto suspended matters. Compared to the environmental conditions of the St. 6 and St. 7, physical factors such as temperature, dissolved oxygen and TSS have statistically no significant difference(p<0.001), but nutrient concentrations were higher at St. 6 than St. 7. It could be suggested from these results that it is important to control the discharge of fresh water by sewage treatment plants located in St. 6 for water quality management.