• 한국지하수토양환경학회지:지하수토양환경
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• 제29권1호
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• pp.18-27
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• 2024

In this study, the pump and fertilize (PAF) was applied to reduce nitrogen infiltration into groundwater at three corn cultivation sites over a three-year period, and its effectiveness was evaluated. PAF involves pumping nitrate-contaminated groundwater and using it for irrigation, thereby replacing the need for chemical fertilizers. This method not only substitutes chemical fertilization, but also reduces nitrogen infiltration into groundwater through root zone consumption. To confirm PAF's effectiveness, an equal amount of nitrogen was applied in each cultivation plot, either through chemical fertilizer or irrigation with nitrate-contaminated groundwater. Regular monitoring of infiltrating pore water and groundwater was conducted in each cultivation plot. The linear regression slope for nitrate concentration in the pore water after repeated application of PAF ranged from -3.527 to -8.3485 mg-N/L/yr, confirming that PAF can reduce nitrate concentration in the pore water. With an increasing proportion of PAF, the infiltrating nitrate mass in pore water was reduced by 42% compared to plots fertilized with chemical fertilizer. Additionally, the linear regression slope of nitrate concentration in groundwater was calculated as -2.2999 and -9.2456 mg-N/L/yr. Therefore, continuous application of PAF in rural areas is expected to significantly contribute to reducing nitrate concentration in groundwater.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권1호
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• pp.1-8
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• 2005

This study was aimed to characterize osteogenic potential of rat bone marrow stromal cells (BMSC) isolated with standard flushing method and investigate the plasticity of transdifferentiation between osteoblastic and adipocytic lineage of cultured BMSC. Unlike aspiration method in human, rat bone marrow was extracted by means of irrigation with culture media that elevates the possibility of co-extraction of committed osteoprogenitor, or preosteoblast or other progenitor cells of several types present inside bone marrow. The cultured stromal cells showed high ALP activity which is representative marker of osteoblast without any treatment. Osteogenic inducers such as Dex and BMP-2 were examined for the evaluation of their effect on osteogenic and adipocytic differentiation of stromal cells, because they function as osteoinductive agent in stromal cells, but simultaneously induce adipogenic differentiation. Osteogenic differentiation was evaluated by measuring alkaline phosphatase activity or mRNA expression of osteoblast markers such as osteopontin, bone sialoprotein, collagen type I and CbfaI, and in vitro matrix mineralization by von Kossa staining. Oil red staining method was used to detect adipocyte and adipocytic marker, aP2 and $PPAR{\gamma}2$ expression was examined using RT-PCR. It can be supposed that irrigation procedure resulted in high portion of already differentiation-committed osteoprogenitor cell showing elevated ALP activity and strong mineralization only under the supplement of $100{\mu}M$ ascorbic 2-phosphate and 10mM ${\beta}$-glycerophosphate without any treatment of osteogenic inducers such as Dex and BMP-2. Dex and BMP-2 seemed to transdifferentiate osteoprogenitor cells having high ALP activity into adipocytes temporarily, but continuous treatment redifferentiated into osteoblast and developed in vitro matrix mineralization. This property must be considered either in tissue engineering for bone regeneration, or in research of characterization of osteogenic differentiation, with rat BMSC isolated by the standard irrigation method.

• 생물환경조절학회지
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• 제14권1호
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• pp.52-55
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• 2005

측지연속 적심과 관수부위를 확대하여 재배한 결과, 정식 후 30일경의 생육특성은 처리간 유의성이 없었다. 그러나 장측지 발생수는 측지연속 적심과 관수부위 확대 처리구가 주당 10.1개로 가장 많았고, 측지연속 적심과 관행관수 처리구는 8.9개이었으며, 측지 1줄 연장재배와 관수부위 확대 처리구는 5.7개, 대조구는 5.6개이었다. 단측지는 4.9-3.7개로 처리간 유의성이 없었지만 총측지 발생수는 측지연속 적심과 더불어 관수부위를 확대시킨 처리구와 측지연속 적심과 관행관수 방법으로 관리한 처리구가 각각 15개와 12.5개로 많았으며, 측지 1줄 연장재배와 관수부위 확대 처리구, 측지 1줄 연장 재배와 관수부위를 확대하지 않은 처리구가 각각 10.6개와 9.7개이었다. 상품수량에 있어서는 측지연속 적심과 관수부위 확대 처리구가 60,380kg/ha으로 대조구에 비해 $38\%$ 증수되었고, 측지연속 적심과 관행관수 처리구가 54,670 kg/ha으로 $25\%$ 증수되었으며, 측지 1줄 연장재배와 관수부위 확대 처리구는 46,400kg/ha으로 $6\%$ 증수효과가 있었다. 즉, 백침계 오이를 재배할 경우, 측지는 연속 적심을 하고 관수부위를 생육 중후기에 이동시켜 주는 것이 측지 1줄기를 연장재배하고 관수 부위를 확대하지 않는 처리에 비해 측지 발생도 많고 수량이 증가하는 것으로 나타났다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.90-90
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• 2022

Nicaragua is located in Central America, climatic conditions are considered tropical dry forest. Statistics reflex that in Nicaragua exits 24,000 rice farmers. National rice production only covers 73% of the national consumption. It exists two sowing system: irrigation and rainfed. Varieties used in both systems are mid-late maturity (120-135 days), there are 14 released varieties for irrigation, eight for rainfed, and eight landraces used in rainfed. The current breeding system (introduction of lines from Colombia) has increased the national production, however, has some limitation due to the lack of enough variability, reducing the proability of finding good genotypes and therefore the possibility of satisfying 100% of the demand. The purpose of this study was to analyze the problems that must be resolved in the short and long term to improve rice productivity in Nicaragua. In this paper we explain some proposal for an improvement plan. The selection of varieties with high adaptability to various cultivation environmental conditions it is necessary, also to thoroughly manage seed purity to supply certified seeds. In rice cultivation technology, it needs to improve seedling standing and weeding effect by improving soil leveling and water-saving cultivation technology. Also, proper fertilization and planting density must be established in irrigated and rain-fed areas. Furthermore, capacity must be strengthened by collecting and training with the most recent agricultural technology information, as well as by revitalizing the union rather than the individual farmer. It is necessary to develop varieties highly adaptable to the Nicaraguan cultivation environment, as well as to expand irrigation facilities and cultivation technology suitable for weather conditions in rain-fed areas. Last, it is necessary to maintain the consistency of agricultural policy for continuous and stable rice production in response to climate change events such as drought or intermittent heavy rain.

• 생물환경조절학회지
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• 제28권4호
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• pp.376-387
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• 2019

최근 수경재배에서 가장 많이 사용되는 친환경 유기배지인 코이어 배지를 사용하였을 때 코이어 칩과 더스트 비율, 급액량에 따라 멜론의 생육과 과실 품질을 분석하고 봄 재배시 코이어 배지를 이용한 멜론 수경재배의 기초 자료를 제공하고자 본 연구를 수행하였다. 실험에 사용한 2 종류의 코이어 배지는 칩과 더스트의 비율이 각각 3:7, 5:5이었으며, 배액률 10, 20, 30% 수준으로 급액하였을 때 멜론의 생육과 품질 변화, 배지의 물리적 화학적 변화를 분석하였다. 배액률 10%를 기준으로 양액을 공급한 처리구는 총 급액량이 주당 91L로 급액량이 가장 많은 배액률 30% 처리구에 비해 약 30% 절감되었다. 총 배액량 또한 급액량이 가장 적은 배액률 10% 처리구에서 주당 10L 이하로 낮은 값을 나타내었다. 더스트 비율이 높은 칩:더스트 3:7 배지는 5:5 배지보다 총 배액량이 약 30-70% 감소하였다. 급액량이 많고 더스트 비율이 높은 3:7 배지를 사용했을 경우 엽생육과 과실 비대가 좋았고 당도는 품종 간 차이가 컸다. 배액률 30%를 기준으로 급액하면 배액률 10% 기준으로 급액하였을 때보다 과중이 21% 증가하였다. 더스트의 비율이 높은 3:7 배지는 5:5 배지보다 용기용수량, 공극률 등 배지 물리성이 우수하였고, 재배 기간 중 네트발현기 이후 배액 EC가 $3.0-6.8dS{\cdot}m^{-1}$로 높은 값을 나타내었다. 재배 품종 특성 및 재배 조건 등을 고려하여 적정한 양수분 관리를 하면 코이어 배지를 이용한 수경재배 시 고품질의 멜론을 생산할 수 있을 것으로 판단된다.

• 한국수자원학회논문집
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• 제53권12호
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• pp.1071-1079
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• 2020

하천수의 통합적인 물관리를 위해서는 농업용수의 목적으로 취수되는 하천수량과 같은 기초자료의 확보가 필수적이다. 취입보를 통해 취수되는 하천수는 농업용수로를 통해 도수되는데, 계측지점의 특성에 맞는 취수량 계측방법이 필요하다. 본 연구에서는 만경강 유역 어우보의 농업용수로 도플러 효과를 이용해 표면유속을 산정하는 전자파 표면유속계를 적용하였는데, 주로 홍수기와 같이 고유량 상황에서 사용되고 있다. 저유량이나 고풍속에서는 표면유속이 단면 전체의 평균유속을 대변하기 어렵기 때문에 연중 지속적인 활용도가 낮다고 평가받고 있어, 농업용수로에서 전자파 표면유속계를 이용한 계측이 적합한지에 대한 검증이 필요한 상황이다. 전자파 표면유속계로 계측한 자료를 실측 유량자료와의 비교를 통해 농업용수로에서의 취수량 자료를 산정하였다. 농업용수로에서 최저유속 약 0.3 m/s, 최저유량 약 1.0 m3/s 이상시 전자파 표면유속계를 이용해 산정되는 일단위 유량은 기준유량 대비 경향성과 정확도가 높은 편인 것으로 확인되었고, 특히, 고유량일때 정확도가 높은 것으로 나타났다. 저유량에서는 양적인 측면에서는 유효한 결과를 얻을 수 있으나, 자료의 경향성이 불안정한 것으로 미루어 저유량시 표면유속으로 단면의 평균유속으로 산정하는 것에는 후속적인 연구가 필요할 것으로 판단한다. 본 연구를 통해 일정 유속 이상의 인공수로에서는 전자파 표면유속계를 통해 취수량을 산정하는 것이 적정한 것으로 사료되어 하천수 사용량 계측의 방안으로서 널리 보급되길 기대한다.

• Archives of Plastic Surgery
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• 제45권5호
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• pp.449-457
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• 2018

Background Although previous studies have focused on determining prognostic and causative variables associated with fistula-related complications after head and neck reconstructive surgery, only a few studies have addressed preventive measures. Noting that pooled saliva complicates wound healing and precipitates fistula-related complications, we devised a continuous suction system to remove saliva during early postoperative recovery. Methods A continuous suction system was implemented in 20 patients after head and neck reconstructive surgery between January 2012 and October 2017. This group was compared to a control group of 16 patients at the same institution. The system was placed orally when the lesion was on the anterior side of the retromolar trigone area, and when glossectomy or resection of the mouth floor was performed. When the orohypopharynx and/or larynx were eradicated, the irrigation system was placed in the pharyngeal area. Results The mean follow-up period was $9.2{\pm}2.4$ months. The Hemovac system was applied for an average of 7.5 days. On average, 6.5 days were needed for the net drain output to fall below 10 mL. Complications were analyzed according to their causes and rates. A fistula occurred in two cases in the suction group. Compared to the control group, a significant difference was noted in the surgical site infection rate (P<0.031). Conclusions Clinical observations showed reduced saliva pooling and a reduction in the infection rate. This resulted in improved wound healing through the application of a continuous suction system.

• Environmental Engineering Research
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• 제16권4호
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• pp.243-252
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• 2011

Several mathematical relationships have been developed to describe bacterial responses to UV irradiation. Pseudomonas aeruginosa was taken as a bacterial model. The results obtained showed that the kinetics of disinfection is far to be as uniform. In fact, application of the model of Chick-Watson in its original form or modification, taking into account the speed change during the disinfection process, has not significantly improved results. The application of both models of Collins-Selleck and Hom constitute a major opportunity to simulate goodly the kinetics of UV disinfection. The results obtained showed that despite the major advantage held by applying the Hom model in this process of disinfection and for all strains studied, the model of Collins-Selleck gave the best results for the description of the UV inactivation process. The design of reactors, operating in continuous disinfection system, requires taking into account the hydrodynamic behaviour of water in the reactor. Knowing that a reduction of 4-log is necessary in the case of wastewater reuse for irrigation, a model integrating the expression of disinfection kinetics and the hydrodynamics through the UV irradiation room was proposed. The results highlight the interest to develop reactors in series working as four perfectly mixed reactors.

• 한국농공학회논문집
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• 제50권1호
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• pp.95-106
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• 2008

Eco-friendly material and implementation methods have become important along with the existing standardized maintenance concept for the irrigation and flood control. However, the intrinsic function of the hydraulic structure is water supply and disaster prevention. Therefore, the material and work methods should be considered both eco-friendliness, durability and safety which are prerequisite elements to maintain the engineering function. In this study eco-friendly material and work methods would be classified into the vegetation based system, eco-friendly concrete system and stone-material system according to the characteristics of material. The quality standard for durability followed KS specification and related regulations. The quality standard for safety and eco-friendliness was set after literature review, and the database was developed using the standard. The structure applicable to onsite - the eco-friendly material and work method were classified based on the function and material of the hydraulic structure. Finally, database has been established for convenient management and selection of the proper material and work method. The eco-friendly material and work method could be searched easily for the convenience of the users, and the web-based data system has been developed for continuous registration of the material and work methods to be developed in the future.

• 한국농공학회논문집
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• 제55권3호
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• pp.51-62
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• 2013

The importance of environmental water has been risen in terms of river ecosystem soundness with preventing stream flow depletion in rural area, while enlarging agricultural reservoir project is conducted under the 4 main river restoration project for supplying more water to 4 main rivers. The aim of this study was to estimate the amount of environmental water release and analyze the release pattern during non-irrigation season in enlarged agricultural reservoirs. The 4 reservoirs (Dansan, Samga, Geumbong, Changpyeong) located on the upper region of Nakdong river were simulated applying the operation rule which was determined by release criteria curves. The simulated results indicated that the more environmental water could be released than the spillway release and continuous release was achieved with smaller range of fluctuation. In case of Changpyeong reservoir, average 506.0 thousand $m^3$ environmental water could be released on Feb., and it was about twice as much as the spillway release before the enlargement, and also, the 18 thousand $m^3$/day environmental water could be supplied to a stream consistently after enlargement. From the results, it was expected that the additional environmental water release will improve stream water flow during dry season in terms of quantity and quality of water.