• 한국농공학회지
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• 제32권3호
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• pp.31-38
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• 1990

The power water flowed out from the multipurpose darn influences the ecosystem approximately because of the low water temperature. An appropriate counter measure to the rising water temperature is needed for growing crops especially when the temperature is below 18˚C in the source of the irrigation water This observational study is practiced in Yong-Doo water warming canal and pond in the down stream of Choong-Ju multipurpose dam and is practiced for analyse and compare the rising effects in actural water temperature by actual measurement with the rising effects of planned water temperatuer by the basic theoritical method and for the help to present the direction in plan establishment through investigate the results afterwards. The results are as follows. 1.The degree of the rise of the water temperature can be decided by $\theta$x=$\theta$o +K L--v.h (T-$\theta$˚)Then, K values of a factor representing the characteristics of the water warming canal were 0.00002043 for the type I. and 0.0000173 for the type II. respectively. 2.A variation of water temperature which produced by the difference effective temperature and water temperature in the water warming canal was $\theta$x1 = 16.5 + 15.9(1-e -0.00018x), $\theta$x2 =18.8 + 8.4( 1-e -0.000298x)for the type I. and $\theta$x, = 19.6 + 12.8 ( 1-e -0.00041x) for the type II. 3.It was shown that the effects of the rise of water temperature for the type I. water warming canal were greater than that of type II. as a resultes of broadening the surface of the canal compared with the depth of water, coloring the surface of water canal and installing the resistance block. 4.In case of the type I. water warming canal, the equation between the air temperature and the degree of the rise of water temprature could be made ;Y= 0.4134X + 7.728 In addition, in case of the type II. water warming canal, the correlation was very low. 5.A monthly variation of the water temperature in the water warming canal was the highest in August during the irrigation period and the water temperature rose with the air temperature until August. However, it was blunted after then. 6.A rising degree of water temperature of the practical value in the water warming pond was higher than that of the theoritical equation by 69% for the type I. and 57% for the type II. Accordingly, it was possible to acquire the result near the practical value.$\theta$w-$\theta$o=[1-exp{ -h(1+2$\psi$) . X($\theta$w-$\theta$0)XC Here, C values are 1.69 for the type I. and 1.57 for the type II. 7.It was shown that the effect of the rise of water temperature was favorable when the thermal absorption was to be good by coloring the surface of the water warming pond and removing the bottom osmosis. 8.By enlarging the surface of water in comparison with the depth, and by having dead area of water in the water warming pond, this structure in the water warming pond is helpful for the rise of water temperature.

• 한국습지학회지
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• 제9권1호
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• pp.69-78
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• 2007

Constructed wetlands and other aquatic systems have been successfully used for waste and wastewater treatment in either temperate or tropical regions. To treat waste or wastewater in a sustainable manner, the integrated eco-engineering designs are explained in this paper with 2 case studies: (i) a combination of vertical-flow constructed wetland (CW) with plant irrigation systemfor fecal sludge management and (ii) integrated CW units with landscaping at full-scale application for domestic wastewater treatment. The pilot-scale study of fecal sludge management employed 3 vertical-flow CW units, each with a dimension of $5{\times}5{\times}0.65m$ (width ${\times}$ length ${\times}$ media depth) and planted with cattails (Typha augustifolia). At the solid loading rate of 250 kg total solids (TS)/$m^2.yr$ and a 6-day percolate impoundment, the CW system could achieve chemical oxygen demand (COD), TS and total Kjeldahl nitrogen (TKN) removal efficiencies in the range of 80 - 96%. The accumulated sludge layers of about 80 - 90 cm was found at the CW bed surface after operating the CW units for 7 years, but no clogging problem has been observed. The CW percolate was applied to 16 irrigation Sunflower plant (Helianthus annuus) plots, each with a dimension of $4.5{\times}4.5m$ ($width{\times}length$). In the study, the CW percolate were fed to the treatment plots at the application rate of 7.5 mm/day but the percolate was mixed with tap water at different ratio of 20%, 80% and 100%. Based on a 1-year data of 3-crop plantation were experimented, the contents of Zn, Mn and Cu in soil of the experimental plots were found to increase with increasing in CW percolate ratios. The highest plant biomass yield and oil content of 1,000 kg/ha and 35%, respectively, were obtained from the plots fed with 20% or 50% of the CW percolate, whereas no accumulation of heavy metals in the plant tissues (i.e. leaves, stems and flowers) of the sunflower is found. In addition to the pilot-scale and field experiments, a case study of the integrated CW systems for wastewater treatment at Phi Phi Island (a Tsunami-hit area), Krabi province, Thailand is illustrated. The $5,200-m^2$ CW systems on Phi Phi Island are not only for treatment of $400m^3/day$ wastewater from hotels, households or other domestic activities, but also incorporating public consultation in the design processes, resulting in introducing the aesthetic landscaping as well as reusing of the treated effluent for irrigating green areas on the Island.

• 한국토양비료학회지
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• 제49권4호
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• pp.355-367
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• 2016

Soil salinization refers to the buildup of salts in soil to a level toxic to plants. The major factors that contribute to soil salinity are the quality, the amount and the type of irrigation water used. The presented review discusses the different sources and causes of soil salinity. The effect of soil salinity on biological processes of plants is also discussed in detail. This is followed by a debate on the influence of salt on the nutrient uptake and growth of plants. Salinity decreases the soil osmotic potential and hinders water uptake by the plants. Soil salinity affects the plants K uptake, which plays a critical role in plant metabolism due to the high concentration of soluble sodium ($Na^+$) ions. Visual symptoms that appear in the plants as a result of salinity include stunted plant growth, marginal leaf necrosis and fruit distortions. Different strategies to ameliorate salt stress globally include breeding of salt tolerant cultivars, irrigation to leach excessive salt to improve soil physical and chemical properties. As part of an ecofriendly means to alleviate salt stress and an increasing considerable attention on this area, the review then focuses on the different plant growth promoting bacteria (PGPB) mediated mechanisms with a special emphasis on ACC deaminase producing bacteria. The various strategies adopted by PGPB to alleviate various stresses in plants include the production of different osmolytes, stress related phytohormones and production of molecules related to stress signaling such as bacterial 1-aminocyclopropane-1-carboxylate (ACC) derivatives. The use of PGPB with ACC deaminase producing trait could be effective in promoting plant growth in agricultural areas affected by different stresses including salt stress. Finally, the review ends with a discussion on the various PGPB activities and the potentiality of facultative halophilic/halotolerant PGPB in alleviating salt stress.

• 한국수자원학회논문집
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• 제48권11호
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• pp.915-923
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• 2015

본 연구에서는 유역 물수지 방법을 기반으로 제주도 지역에 적합한 용수량 산정방법을 제안하고, 이를 기반으로 4개 하천유역에 대해 지역 및 고도에 따른 증발산량, 용수량 특성을 평가하였다. SWAT-K 유역모형을 적용하여 1992~2013년 기간에 대해 잠재증발산량과 실제증발산량을 산정하고, 이로부터 유역의 순물소모량을 추정하였다. 고도증가에 따라 잠재증발산량은 선형으로 감소하는 반면, 실제증발산량은 강수량에 의한 토양내 가용수분의 증가로 인해 약 400m 고도까지는 증가하다가 이후 고도에서는 식생, 가용수분의 감소, 저온현상 등으로 인해 감소하는 것으로 나타났다. 고도에 따른 순물소모량은 강정천유역을 제외한 3개 유역에서 고도증가에 따라 순물소모량이 선형적으로 감소하는 것으로 나타났으며, 고도 200m 이하 작물경작지에서의 순물소모량은 연간 559~680m로 분석되었다. 추정된 용수량을 실제 관정 이용량과 비교한 결과, 여름철(6~8월) 양수량은 급수관행으로 인해 크게 증가하는데 비해, 작물경작에 따른 순물소모량은 오히려 감소하는 것으로 나타났다. 이에 대해서는 향후 더 많은 관정 이용량과 추가적인 대상지역을 반영하여 분석이 필요할 것으로 판단된다.

• 대한임상독성학회지
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• 제7권2호
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• pp.121-126
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• 2009

Purpose: We investigated the clinical characteristics and demographics of patients who suffered from hydrofluoric acid chemical injury and the mechanism of damage. Methods: We retrospectively reviewed the medical records of patients who were exposed to hydrofluoric acid from March 2004 to March 2009 and who were seen at the emergency centers in two university teaching hospitals. Results: Forty four patients out of 47 patients suffered from chemical burn, while the injuries of the remaining 3 could not be identified by the medical records. A total of 17 hydrofluoric acid chemical injury patients were enrolled during the study period, and their mean age was $29.6{\pm}7.0$. All the patients were accidentally injured by contact with the material and none of them inhaled or ingested the material. Only 6 patients wore appropriate protective equipments and 5 underwent the water irrigation for more than 10 minutes. The most common exposure area was the hand and forearm (70.5%). Less than 1% of all of the patients had their total body surface (TBS) exposed to hydrofluoric acid (mean=0.35%). The mean time interval from calcium gluconate administration to pain relief was $33.6{\pm}8.8$ hours. Conclusion: When exposed to hydrofluoric acid, it is important to wear protective equipment and undergo water irrigation for more than 10 minutes. Pain and skin damage were observed in all the patients. After treatment, we concluded that administration of calcium gluconate and pain killers was successful in relieving pain, and the prognosis was also positive for the admitted and followed up patients when less than 1% of the TBS was exposed.

• Weed & Turfgrass Science
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• 제4권4호
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• pp.405-412
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• 2015

학교 운동장은 체육활동 외에도 학생들과 지역 주민들의 다양한 여가 활동이 이루어지는 중요한 공간이다. 본 연구는 운동장 조성 및 잔디관리 현황 조사를 통하여 천연잔디학교 운동장의 문제점을 파악하고 앞으로 학교 운동장 잔디의 품질향상을 위한 기초자료로 활용하고자 수행되었다. 경기도내에 천연잔디 학교 운동장 40개소를 방문하여 운동장관리 관계자와의 질문 답변과 현장조사 결과 학교당 운동장 면적은 평균 $3,890m^2$, 1인당 운동장 면적은 평균 $12m^2$로 나타났다. 운동장 잔디관리는 학교 관계자에 의한 자체 관리가 조사 대상 학교의 95%로 나타났고, 잔디관리 비용은 조사된 학교의 대부분인 90%가 5백만원 이하의 적은 비용으로 유지 관리되고 있었다. 천연잔디 학교 운동장의 문제점으로는 잔디관리의 어려움과 잔디관리에 소요되는 비용 부담 등으로 나타났다. 운동장 잔디관리의 가장 큰 어려움으로 잡초관리와 관수작업으로 나타났다. 학교 운동장은 조사대상의 97.5%가 한국잔디로 조성되어 있었으며 시비 년2회, 깎기 년6회, 잡초방제 월2회, 관수는 위조발생시 처리하는 수준으로 나타나 많은 학교가 최소관리 수준에서 잔디관리가 이루어지고 있는 것으로 조사되었다. 학교 운동장의 잔디상태는 양호한 곳이 14개소, 개선을 요하는 수준에 있는 학교가 26개소로 관배수시설 확충과 함께 기본적인 잔디관리 수준을 높임과 동시에 잔디보식, 통기, 배토 등과 같은 적극적인 갱신작업을 통하여 운동장 잔디 품질 향상이 필요한 것으로 판단되었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권2호
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• pp.7-15
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• 2014

This study was conducted to understand the chemical characteristics of groundwater in carbonate areas of Korea. In this study, data on pH, electric conductivity (EC), $Ca^{2+}$, $Mg^{2+}$, $Na^+$, $K^+$, $Cl^-$, $SO_4{^{2-}}$, and $HCO_3{^-}$ were collected from 97 wells which were installed in various carbonate rock regions of Korea. The pH values ranged from 5.7 to 9.9, and the average value was 7.3. The concentration range showed differences between the maximum value of $HCO_3{^-}$ and the medium to minimum values of $Ca^{2+}$, $Mg^{2+}$, $Na^+$, $Cl^-$, $SO_4{^{2-}}$, and $K^+$ in the study area. The average value of EC was $374{\mu}S/cm$, higher than in granite and gneiss areas, where the value is $176{\mu}S/cm$. Most of the groundwater was type $Ca-HCO_3$, and some was type $Mg-HCO_3$. The relationship between $Ca^{2+}$, $Cl^-$, and $HCO_3{^-}$, respectively, and EC showed relatively significant positive correlations compared to the other dissolved components. However, the determination coefficients for $Mg^{2+}$, $Na^+$, $SO_4{^{2-}}$, and $K^+$ were very low less than 0.2. These results indicate that the source of $Ca^{2+}$ and $Mg^{2+}$ is relatively simple (carbonate dissolution) compared to other sources. The sources of $Na^+$, $K^+$, $Cl^-$, $SO_4{^{2-}}$, and $HCO_3{^-}$ might be not only water-rock interactions, but also irrigation return flow, because many groundwater wells had been developed for irrigation purposes. Subsequently, the influence of agriculture on groundwater chemistry was evaluated using a cumulative plot of $SO_4{^{2-}}$. The threshold value of $SO_4{^{2-}}$ calculated from the cumulative frequency curve was 29.2 mg/L. Therefore, 12.4% of all the groundwater wells were affected by agricultural activity.

• 원예과학기술지
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• 제34권3호
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• pp.414-423
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• 2016

본 연구는 환경오염 감소와 암면 배지의 대체를 위해 새롭게 개발된 생육배지인 phenolic foam의 토마토 육묘용 배지로써의 이용가능성을 구명하기 위해 수행되었다. 토마토 'Madison' 품종을 4종류의 펠릿형 Grodan rockwool(GRW), UR rockwool(URW), phenolic foam LC(LC), phenolic foam LC-lite(LC-lite) 인공배지에 파종하여 육묘 후 19일 후에 4종류의 큐브형 인공배지에 이식하였다. 종자는 식물생장 챔버에($25{\pm}2^{\circ}C$, 상대습도 $90{\pm}5%$, 암발아) 4일 동안 발아시켰고, 발아가 시작 된 후에는 유리온실로 옮겨 두상 관수로 양액을 관수하였다. 토마토의 초장, 엽수, 엽면적, 생체중 및 건물중은 LC-lite 펠릿에서 육묘한 후 URW 큐브로 이식한 묘에서 생육이 우수하였다. 뿌리 등급은 LC 펠릿에서 육묘 후 LC와 LC-lite 큐브로 이식한 처리에서 가장 우수하였다. 배지의 화학성은 모든 배지에서 토마토의 생육에 안정적인 범위였다. URW의 물리성은 용기 용수량, 기상률, 총 공극에서 높은 값을 나타냈다. 그러므로, 신개발 배지인 phenolic foam은 토마토 묘의 초기 육묘와 뿌리 발달에 적합하여 암면 대체 가능성을 입증하였다.

• Restorative Dentistry and Endodontics
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• 제31권3호
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• pp.186-191
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• 2006

본 연구의 목적은 근관내 약제로 사용되는 수산화칼슘의 제거방법이 근관충전 후 치근단 미세누출에 미치는 영향을 알아보기 위함이다. 70개의 발거된 단근치를 엔진구동형 ProFile로 근관형성한 후 수용성 수산화칼슘 제제를 1주일간 적용하고 두 군으로 나누어 각기 다른 방법으로 제거하였다. A군은 NaOCl로 근관세정만을 시행하였으며, B군은 근관형성 시 사용된 file보다 한 단계 큰 크기의 ProFile을사용하여 근관을 재형성한 후 NaOCl로 세척하였다. 근관충전 후 전기화학적 방법으로 24일 동안 치근단 누출을 측정, 비교하였다. 본 연구의 결과 수산화 칼슘 제거를 위한 두가지 방법은 근관충전후 치근단 미세누출에 있어서 차이가 없음을 알 수 있었다.

• 한국수자원학회논문집
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• 제54권10호
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• pp.779-793
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• 2021

총일차생산량은 물 스트레스와 환경 변수에 의해 크게 영향을 받는다. 총일차생산량과 환경변수의 상관관계는 Moderate Resolution Imaging Spectroradiometer (MODIS) 알고리즘과 process-based model에 적용되어 총일차생산량을 계산하는데 활용된다. 그러나 MODIS 알고리즘에서는 물 스트레스를 수증기압차이(vapor pressure deficit)로만 고려하고 있으며, process-based model에서도 제한된 변수만으로 물 스트레스를 표현하여 총일차생산량을 산출하고 있다. 본 연구에서는 에디 공분산 기법, MODIS 알고리즘, 그리고 Community Land Model 4 (CLM 4) 시뮬레이션 결과에서 얻어진 총일차생산량이 환경 변수와 가지는 상관관계를 평년과 가뭄연도를 대상으로 분석하였다. 물 스트레스를 대표하는 지수는 수증기압차이와 evaporative fraction (EF)가 사용되었다. 본 연구에서는 structural equation modeling (SEM)을 활용하여 환경 변수와 EF가 총일차생산량에 끼치는 영향을 수치화하여 평가하였다. SEM을 통해 상관성을 분석한 결과, 수증기압차이가 과소평가될 경우 MODIS 알고리즘과 CLM 4 시뮬레이션에서 생산된 총일차생산량이 수증기압차이로부터 받는 영향이 제한적임을 확인하였다. 에디 공분산 기법으로 산출한 총일차생산량의 상관성 분석 결과, 경작지에서는 관개작업으로 인해 수증기압차이가 총일차생산량에 끼치는 영향이 감소하였으나 MODIS와 CLM 4에서 산출된 총일차생산량 데이터는 이러한 관개작업의 영향을 설명하는데 제한적이었다. 본 연구결과는 MODIS와 CLM 4에서 산출된 총일차생산량의 특성을 이해하고 한계를 분석하는 연구에 도움을 줄 것으로 예상된다.