• 한국농공학회지
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• 제44권7호
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• pp.64-73
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• 2002

This study was performed to evaluate effects of physical characteristics of both watershed and reservoir on nutrient-chlorophyll relationship in Korean reservoirs. Simple linear models were developed with published data in Korea including 415 reservoirs and 11 multi-purpose dams, and physico-chemical parameters of reservoirs and characteristics relationship of models were analyzed. Theoretical residence time in Korean reservoirs was strongly correlated with the ratio of TA/ST (drainage area + surface area / storage volume) in the logarithmic function. As a result of monthly nutrients-chlorophyll-a regression analysis, significant Chl-a-TP relationship appeared during May～July. The high Chl-a yields per total phosphorus appeared during this time (R$\^$2/=0.51, p<0.001, N= 1088). Chlorophyll-a demonstrated much stronger relationship with TP. than TN. Seasonal algal-nutrient coupling were closely related with N:P ratio in the reservoir water, and it was, in turn, dependent on the monsoon climatic condition (precipitation). Based on the results of regression analysis and high N:P ratio, a major limiting factor of algal growth appeared to be phosphorus during this time. Unlikely TA/ST ratio, DA/SA ratio (drainage area f surface area) was likely to influence directly on the nutrient-Chl-a relationship, indicating that if storage volume and inflowing water volume were the same, algal biomass could be developed more in reservoirs with large surface area. Thus, DA/SA ratio seemed to be an important factor to affect the development of algal biomass in Korean reservoirs. With low determination coefficient of TP-Chl-a relationship, our findings indicated not only nutrient (phosphorus) but also other physical factors, such as DA/SA ratio, may affect algal biomass development in Korean reservoirs, where actual residence time appears to be more closely related to reservoir surface area rather than storage volume.

• 한국수자원학회논문집
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• 제51권2호
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• pp.121-129
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• 2018

도시 지역의 불투수층에 내린 강우는 지표면을 따라 흐르다가 대부분 우수관으로 유입되어 유역에서 배출된다. 그러므로 도시 우수관의 설계빈도를 결정하고 설계홍수량을 결정하는 일은 도시 홍수 저감을 위한 구조적인 대책 중 가장 우선적으로 고려되어야 하고, 또 가장 중요한 대책이기도 하다. 그러나 최근 들어 기후변화 등으로 인해 짧은 시간에 큰 강우강도의 호우가 발생하는 일이 잦아지고 있다. 이런 형태의 호우는 불투수면이 많은 도시 지역에서 갑작스럽게 유출량을 증가시켜 증가된 유출량이 일시에 우수관으로 유입되지 못하고 일시적이고 국부적인 홍수를 야기하기도 한다. 그러므로 도심지의 홍수 저감을 위해 우수관망의 적절한 설계가 매우 중요하다. 그러나 무한정 큰 관경의 우수관을 건설하는 것은 경제적으로 타당한 방법이 될 수 없으므로, 적절한 크기의 우수관을 설계하고 유출해석의 신뢰도를 높이기 위한 노력이 필요하다. 그러므로 본 연구에서는 과거 홍수피해가 빈번히 발생했던 도시유역들 중 유역면적과 우수관망의 구조가 다른 4개의 도시를 서울과 부산지역에 선정하여 다양한 강우에 따른 유출해석을 실시하였다. 서울과 부산 기상관측소의 과거 호우 자료에 대한 EPA-SWMM 모형에서의 유출해석 결과, 첨두강우량의 변화에 따른 첨두유출량의 변화를 선형회귀모형으로 분석하였다. 회귀모형의 결정계수와 95% 신뢰구간 및 변동계수를 비교하고, 수계밀도 개념을 적용하여 첨두유출량의 변화를 해석한 결과, 우수관망이 조밀하게 건설되어 수계밀도가 높을수록 증가된 첨두강우량에 따라 함께 증가하는 첨두유출량의 예측이 상대적으로 정확하게 가능함을 확인하였다. 이는 수계밀도가 높을수록 유출응답이 빨라지고 국부적인 우수관의 통수능 부족으로 발생하는 침수의 발생 가능성이 낮아지기 때문인 것으로 보이며, 갑작스러운 강우에 대한 대응이 수월함을 의미한다. 이러한 우수관의 구조적인 특성에 따른 유출 응답 속도를 고려하여 우수관을 설계한다면, 보다 효율적인 우수관 설계가 가능할 것으로 판단된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권6호
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• pp.544-549
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• 2009

Failure to use effective methods of reduction, fixation and immobilization may lead to osteomyelitis with the exposed necrotic bone, as the overzealous use of transosseous wires & plates that devascularizes bone segments in the compound comminuted fractures of mandible. Once osteomyelitis secondary to fractures has become established, intermaxillary fixation should be instituted as early as possible. Fixation enhances patient comfort and hinders ingress of microorganisms and debris by movement of bone fragments. Teeth and foreign materials that are in the line of fracture should be removed and initial debridement performed at the earliest possible time. Grossly necrotic bone should be excised as early as possible ; no attempt should be made to create soft tissue flaps to achieve closure over exposed bone. The key to treatment of chronic osteomyelitis of the mandible is adequate and prolonged soft tissue drainage. If good soft tissue drainage is provided over a long period, sequestration of infected bone followed by regeneration or fibrous tissue replacement will occur so that appearance and function are not seriously altered. Localization and sequestration of infected mandible are far better performed by natural mechanism of homeostasis than by cutting across involved bone with a cosmetic or functional defect. As natural host defenses and conservative therapy begin to be effective, the process may become chronic, inflammation regresses, granulation tissue is formed, and new blood vessels cause lysis of bone, thus separating fragments of necrotic bone(sequestra) from viable bone. The sequestra may be isolated by a bed of granulation tissue, encased in a sheath of new bone(involucrum), and removed easily with pincettes. This is a case report of the long-term conservative drainage care in osteomyelitis associated with mandibular fractures.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1798-1802
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• 2007

The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation.The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall.The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

• 산업기술연구
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• 제27권A호
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• pp.95-102
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• 2007

The practice of business estimate flood discharge by rainfall-flow relation that is easy collection of observation data. The important factor is rainfall, coefficient of runoff, and drainage area for analysis of runoff-flow relation. The practice of business usually use probability rainfall that use a weighted average value after each observation post estimate probability of non-same time. It has more error than same time probability rainfall, and it can excess of estimation because it can't consider space distribution of rainfall. The study of result showed similar aspect with existing ARF but width of coefficient become smaller. And the comparison of peak flow did not different what used by ARF and same time probability rainfall(A group). But non-same time probability rainfall is bigger 25% more than another(B group). Between A group and B group of the difference increased with the lapse of time.

• Journal of Korean Neurosurgical Society
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• 제49권4호
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• pp.217-221
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• 2011

Objective : This paper presents data from a retrospective study of endoscopic third ventriculostomy (ETV) in patients with shunt malfunction and proposes a simple and reasonable post-operative protocol that can detect ETV failure. Methods : We enrolled 19 consecutive hydrocephalus patients (11 male and 8 female) who were treated with ETV between April 2001 and July 2010 after failure of previously placed shunts. We evaluated for correlations between the success rate of ETV and the following parameters : age at the time of surgery, etiology of hydrocephalus, number of shunt revisions, interval between the initial diagnosis of hydrocephalus or the last shunt placement and ETV, and the indwelling time of external ventricular drainage. Results : At the time of ETV after shunt failure, 14 of the 19 patients were in the pediatric age group and 5 were adults, with ages ranging from 14 months to 42 years (median age, 12 years). The patients had initially been diagnosed with hydrocephalus between the ages of 1 month 24 days and 32 years (median age, 6 years 3 months). The etiology of hydrocephalus was neoplasm in 7 patients; infection in 5; malformation, such as aqueductal stenosis or megacisterna magna in 3; trauma in 1; and unknown in 3. The overall success rate during the median follow-up duration of 1.4 years (9 days to 8.7 years) after secondary ETV was 68.4%. None of the possible contributing factors for successful ETV, including age (p=0.97) and the etiology of hydrocephalus (p=0.79), were statistically correlated with outcomes in our series. Conclusion: The use of ETV in patients with shunt malfunction resulted in shunt independence in 68.4% of cases. Age, etiology of hydrocephalus, and other contributing factors were not statistically correlated with ETV success. External ventricular drainage management during the immediate post-ETV period is a good means of detecting ETV failure.

• Journal of Chest Surgery
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• 제49권6호
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• pp.421-426
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• 2016

Background: Median sternotomy is the standard approach for atrial septal defect (ASD) closure. However, minimally invasive cardiac surgery (MICS) has been introduced at many centers in adult/grown-up congenital heart patients. We retrospectively reviewed the results of right anterolateral thoracotomy compared with conventional median sternotomy (CMS) for ASD closure at Seoul National University Hospital. Methods: We retrospectively analyzed 60 adult patients who underwent isolated ASD closure from January 2004 to December 2013 (42 in the CMS group, 18 in the MICS group). Preoperative, operative, and postoperative data were collected and compared between the 2 groups. Results: The MICS group was younger (44.6 years vs. 32.4 years, p=0.002) and included more females (66.7% vs. 94.4%, p=0.025) than the CMS group. Operation time (188.4 minutes vs. 286.7 minutes, p<0.001), cardiopulmonary bypass time (72.7 minutes vs. 125.8 minutes, p<0.001), and aortic cross-clamp time (25.5 minutes vs. 45.6 minutes, p<0.001) were significantly longer in the MICS group. However, there were no significant differences in morbidity and mortality between groups. Only chest tube drainage in the first 24 hours (627.1 mL vs. 306.1 mL, p<0.001) exhibited a significant difference. Conclusion: MICS via right anterolateral thoracotomy is an alternative choice for ASD closure. The results demonstrated similar morbidity and mortality between groups, and favored MICS in chest tube drainage in the first 24 hours.

• 한국토양비료학회지
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• 제47권4호
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• pp.284-289
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• 2014

Farmers in highlands in South Korea pile up 20 to 30 cm of saprolites, mostly granite- or granite-gneiss-weathered materials, on surface of arable lands every three to five years to compensate eroded soil and sometimes to discontinue soil-borne diseases. Immediate increases of infiltration and percolation rates are expected with coarse textured saprolites while soil drainage becomes poorer in a long-term. In this study, we analyzed mineralogical characteristics and micro-morphology of plow pan to investigate processes making impermeable layers. Soil samples were collected from plow pan, usually located at approximately 20 cm soil depth and at the lower part of piled saprolites, in arable lands in Hoenggye 5-ri, Daekwanryeong-myeon, Gangwon-do (N37.7, E128.7) in which saprolites were added 2, 4, and 8 years ago; saprolites were transported from similar areas. The saturated hydraulic conductivity decreased over time. Based on soil thin section pedography, quartz and feldspar accounted for a majority of minerals. The size of feldspar decreased and macropores became filled with clay or silt particles over time, which implies that macropores were packed with particles weathered from feldspar. The X-ray diffraction (XRD) analysis indicated that intensity of feldspar decreased over time and the reverse was true for kaolinite and illite, indicating that feldspar and mica weathering induced formation of kaolinite and illite. Conclusively, deteriorated drainage by formation of impermeable layers in farms with piled saprolites was caused by accumulation of clay minerals such as kaolinite and illite in macropores; illite and kaolinite can be formed by weathering of mica and feldspar, respectively.

• The International Journal of Costume Culture
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• 제4권2호
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• pp.86-93
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• 2001

Agricultural drainage salt generated during irrigation of crops in San Joaquin Valley, California exceeds 600,000 tons annually and cumulates in the field in a rapid rate. As a result, the waste is taking out more farmlands for salt storage and disposal, imposing serious concerns to environment and local agricultural industry. in searching for a potential solution to reduce or eliminate the waste, this research explored feasibility of producing a value-added product, sodium sulfate, from the waste and utilizing the product in textile dyeing. The result indicated that sodium sulfate could be produced the salt and could be purified by a recrystalization method in a temperature range within the highest and lowest daily temperatures in summer in the valley. Re recovered sodium sulfate samples, with purifies ranging from 67% to 99.91, were compard with commercially available sodium sulfate in directive dyeing of cotton fabrics. Direct Yellow 27 and direct Blue 1 had similar exhaustions among Na₂So₄Ⅰ, Na₂So₄Ⅱ, Na₂So₄Ⅲ and V which had similar ratios of sodium sulfate and sodium chloride in recovered salts. Na₂So₄Ⅳ had high exhaustion despite low ratios of sodium sulfate and sodium chloride. In direct Red 80, exhaustion depends more on the ratios of sodium sulfate and sodium chloride than sodium chloride. Na₂SO₄Ⅳ and Na₂SO₄V with high ratios of sodium chloride had more exhaustion than Na₂So₄and Na₂So₄Ⅲ with low ratios of sodium chloride. Generally, directive dyeing using recovered salts from farm drainage has similar or more excellent exhaustion than directive dyeing using commercial sodium sulfate.

• 한국토양비료학회지
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• 제46권6호
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• pp.458-462
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• 2013

A drainage ditch is normally a component of drainage networks in farming systems to remove surplus water, but at the same time, it may act as a major conduit of agricultural nonpoint source pollutions such as sediment, nitrogen, phosphorus, and so on. The hybrid turbidity reduction system using biodegradable check dam and synthetic polymer was developed in this study to manage pollutant discharge from agricultural farmlands during rainfall events and/or irrigation periods. The performance of this hybrid system was assessed using a laboratory open channel sized in 10m-length and 0.2m-width. Various check dams using agricultural byproducts (e.g., rice straw, rice husks, coconut fiber and a mixture of rice husks and coconut fiber) were tested and additional physical factors (e.g., channel slope, flowrate, PAM dosage, turbidity level, etc.) affecting on turbidity reduction were applied to assess their performance. A series of lab experiments clearly showed that the hybrid turbidity reduction system could play a significant role as a supplementary of Best Management Practice (BMP). Moreover, the findings of this study could facilitate to develop an advanced BMP for minimizing nonpoint source pollution from agricultural farmlands and ultimately to achieve the sustainable agriculture.