• 펄프종이기술
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• 제40권2호
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• pp.1-7
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• 2008

The trend of using more hardwood and recycled fibers, and closing more tightly of the paper mill white water system has resulted in build-up of fines as well as organic and inorganic contaminants in the white water. This changes in papermaking wet end requires developing chemical additive system that provides good fiber retention and drainage in closed white water system. In this study the effect of charge densities and chemical characteristics of microparticle systems consisted of cationic guar gums and anionic colloidal silica sols on drainage and retention have been examined. Results showed that higher charge density of cationic guar gum and anionic colloidal silica sol gave better retention and drainage. Particularly highly structured silica gave greater retention efficiency.

• 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.

• 한국조경학회지
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• 제25권1호
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• pp.62-72
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• 1997

As a site is built up, runoff increases inevitably. This results in water deficit in the site and possible downstream flooding. It may cause irreversible site ecosystem disturbance. This study examined some techniques of increasing infiltration rates in a site development. The possible effects of applying such techniques at a new town development are calculated for four types of land uses-business area, low/high density residential areas, and park area- of Bun-Dang New Town. If the higher infiltration drainage systems are introduced, there may be additional infiltration of the precipitation as much as 59.8% in business area, 74.6% in low density residential area, 51.4% in high density residential area and 32.7% in park area. This much increase of infiltration, or decrease of runoff, may improve site water balance, and thus keep the site ecosystem much healthier.

• 한국작물학회지
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• 제23권2호
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• pp.61-67
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• 1978

(1) 배수조건별 시비량과 재식밀도를 증가함에 따라 수수, 일수입수가 증가하는 경향이었고 암거배수가 무배수보다 수수는 적었으나 일수입수는 많았다. (2) 등숙비율, 등숙도, LWR도 암 영배수에서 좋았고 시비량과 재식밀도를 높일수록 단위면적당 높은 경향이었다. (3) $\alpha$-Na산화력은 암 배수가 각처리 모두 높았고 일정면적당 근활력은 다비밀식일수록 증가 경향이었으며 무배수구는 N 30kg에 80주처리에서 높았다. (4) 1일 32mm의 수직배수로 인한 양분용설로 암거 배수구가 무배수구에 비하여 초기생육은 부진했으나 후기 생육상에 호전을 보여 동화물질의 축적, 엽면적등에 높은 수치을 보였고 시비량을 증가할수록 높았으며 재식밀도를 높여줌에 따라선 주당묘수간에는 낮았으나 $m^2$당간에는 높았다. (5) 이상의 결과 10a당 수량은 암거배수가 무배수보다 8% 증수하였고 시비량 및 재식밀도를 증가함에 따라 증수하였다.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2008년도 공동추계학술대회
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• pp.151-152
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• 2008

The planning and management of the watershed environment require huge amount of information regarding almost all aspects of natural and manmade features of the area. Until lately this study could be achieved through days of exhaustive surveys map generation and tedious calculations. Remote sensing and GIS provides huge temporal database for an area and GIS provides the powerful tool for spatial and non-spatial analysis of remotely sensed data. The paper highlights the assessment of land potentiality using weighed overlay analysis with drainage density, soil, slope and lineament, LULC map was used to identify the utilization area of the watershed. The arithmetic overlay analysis was performed with potential and utilization layer to assess the availability of land for the future development.

• 한국물환경학회지
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• 제26권5호
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• pp.761-767
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• 2010

This study introduces a model of territorial analysis on Chungcheongnam-do Nonsan-chun valley area, which gives an example of a method of selecting the management area for non-point pollution source from land use to help eliminate its source. High discharge load per unit area signify high level of land ratio with high level of basic unit of development load (including factory sites, school sites, roadways), which mean that there are a significant level of urbanization. It is these areas with the examination of the water quality of the nearby river that should be considered as the management area for non-point pollution source. Thus, the management area for non-point pollution source should be sought in areas with high discharge load per unit area and high density of water pollution area. When level of drainage is high the pollution density level is relatively lower, and when the level of drainage is low the density level is relatively higher. The level of pollution from non-point pollution source is much lower with more water flowing through. The possible non-point pollution source areas that were selected with these standards were then examined with the distance from the river, the slope angle, land usage, elevation, BOD discharge density load, T-N discharge density load, T-P discharge density load, and were given a level one through five. Out of the possible areas Nonsan-si Yeonmu-eup Anshim-li was the densest area, and it was given level one. The level one area should be examined further with the field analysis to be selected as the actual management area for non-point pollution source.

• Journal of Korean Neurosurgical Society
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• 제43권1호
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• pp.11-15
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• 2008

Objective : Burr hole drainage has been widely used to treat chronic subdural hematoma (CSDH). However, the incidence of recurrent CSDH varies from 3.7 to 30% after surgery. The authors attempted to elucidate the risk factors associated with the recurrence of CSDH in one burr hole drainage technique. Methods : A total of 255 consecutive cases who underwent one burr hole drainage for CSDH were included in this study. Twenty-four patients (9.4%) underwent a repeated operation because of the recurrence of CSDH. We analyzed retrospectively the demographic, clinical and radiologic factors associated with the recurrence of CSDH. Results : In this study, two risk factors were found to be independently associated with the recurrence of CSDH. The incidence of CSDH recurrence in the high- and mixed-density groups was significantly higher than those in the low- and iso-density groups (p<0.001). Bleeding tendency such as in leukemia, liver disease and chronic renal failure was also significantly associated with recurrence of CSDH (p=0.037). Conclusion : These results suggest that high- and mixed- density shown on computed tomographic scan was closely relates with a high incidence of recurrence. Therefore, the operation could be delayed in those cases unless severe symptoms or signs are present. Reoperation using the previous burr hole site is a preferred modality to treat the recurrent CSDH.

• Journal of Korean Neurosurgical Society
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• 제40권4호
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• pp.262-266
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• 2006

Objective : Chronic subdural hematoma[CSDH] is usually treated by burr hole trephination and hematoma evacuation with closed drainage and the surgical result is relatively good in most reported series. But, some patients experience the recurrence of CSDH. We study the clinical factors related to the recurrence of CSDH. Methods : 213 consecutive patients with CSDH who were treated with burr hole trephination and hematoma evacuation with closed drainage. The medical records, radiologic findings were reviewed retrospectively and clinical factors associated with the recurrent CSDH were analysed statistically. Results : 8.4%[18 cases] of the 213 patients who were treated due to CSDH were recurred. The demographic variables such as age, sex, coexisting diseases were not related to the recurrence. The preoperative hematoma thickness and postoperative hematoma thickness were not associated with the recurrence. The only factor related to the recurrence is postoperative hematoma density in this study. Conclusion : This study shows that postoperative hematoma density was strongly related to the recurrence of CSDH. However, several factors associated with the recurrent CSDH were reported in the liletrature. Thus, further study will be needed to uncover the factors related to the recurrence of CSDH.

• Journal of Trauma and Injury
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• 제25권4호
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• pp.209-216
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• 2012

Purpose: The objectives of this study are to classify chronic subdural hematomas based on brain computerized tomographic scan (CT scan) findings and to determine the mechanism of evolution and treatment methods. Methods: One hundred thirty-nine patients who were diagnosed with a chronic subdural hematoma and who available for follow up assessment 6 months post-surgery were analyzed retrospectively. The presence of trauma and past medical history were reviewed and evaluation criteria based on brain CT scan findings were examined. Results: Initial brain CT scans revealed a chronic subdural hematoma in 106 patients, a subdural hygroma in 24 patients, and an acute subdural hematoma in 9 patients. In all cases where the initial acute subdural hematoma had progressed to a chronic subdural hematoma, final was a hypo-density chronic subdural hematoma. In case where the initial subdural hygroma had progressed to a chronic subdural hematoma, the most cases of hematoma were hyper-density and mixed-density chronic subdural hematoma. In total, 173 surgeries were performed, and they consisted of 97 one burr-hole drainages, 70 two burr-hole drainages and 6 craniotomies. Conclusion: This study demonstrates that rebleeding and osmotic effects are mechanisms for enlarging of a chronic subdural hematoma. In most cases, one burr-hole drainage is a sufficient for treatment. However, in cases of mixed or acute-on-chronic subdural hematomas, other appropriate treatment strategies are required.

• 한국지하수토양환경학회지:지하수토양환경
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• 제28권6호
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• pp.45-57
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• 2023

To assess land subsidence estimation and preparedness in the Geum River basin, this study applied GIS techniques and identified six key areas. The Geum River basin has experienced an increase in heavy rainfall since late 2010, and four study areas have shown an increase in groundwater levels. Land subsidence primarily occurred from June to September, with higher rainfall years in 2020 and 2023. Approximately 83.6% of land subsidence in Chungcheongbuk-do province occurred in Cheongju-si, mainly attributed to aging sewage pipes. The regions experiencing population growth have likely led to the construction of underground infrastructures and sewer pipes. Thus, it is considered that various factors, including sewage pipe leaks, precipitation, slope gradient, low drainage density, and groundwater level fluctuations, have contributed to land subsidence. Improving land subsidence estimation involves incorporating additional natural factors and human activities.