• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.35-35
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• 2017

How do plants take up water from soils especially when water is scarce in soils? Plants have a strategy to respond to water deficit to manage water necessary for their survival and growth. Plants regulate water transport inside them. Water flows inside the plant via (i) apoplastic pathway including xylem vessel and cell wall and (ii) cell-to-cell pathway including water channels sitting in cell membrane (aquaporins). Water transport across the root and leaf is explained by a composite transport model including those pathways. Modification of the components in those pathways to change their hydraulic conductivity can regulate water uptake and management. Apoplastic barrier is modified by producing Casparian band and suberin lamellae. These structures contain suberin known to be hydrophobic. Barley roots with more suberin content from the apoplast showed lower root hydraulic conductivity. Root hydraulic conductivity was measured by a root pressure probe. Plant root builds apoplastic barrier to prevent water loss into dry soil. Water transport in plant is also regulated in the cell-to-cell pathway via aquaporin, which has received a great attention after its discovery in early 1990s. Aquaporins in plants are known to open or close to regulate water transport in response to biotic and/or abiotic stresses including water deficit. Aquaporins in a corn leaf were opened by illumination in the beginning, however, closed in response to the following leaf water potential decrease. The evidence was provided by cell hydraulic conductivity measurement using a cell pressure probe. Changing the hydraulic conductivity of plant organ such as root and leaf has an impact not only on the speed of water transport across the plant but also on the water potential inside the plant, which means plant water uptake pattern from soil could be differentiated. This was demonstrated by a computer simulation with 3-D root structure having root hydraulic conductivity information and soil. The model study indicated that the root hydraulic conductivity plays an important role to determine the water uptake from soil with suboptimal water, although soil hydraulic conductivity also interplayed.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.64-67
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• 2006

The main purpose of this research was to investigate the effects of urbanization on the groundwater system in the Gap river basin, a sub-basin of the Geum river basin. In this analysis, we constructed a water cycle analysis system using SWAT. Then, changes in soil moisture and recharge rate due to land-use changes were investigated using different land-use data estimated in 1975 and 2000. Simulation results were analyzed for both draught (2001) and flood (2003) years to take into account different hydrologic conditions. It was shown that recharge rate in the most urbanized area (31% change) was reduced by 17% for both periods due to urbanization. The results also indicated that soil moisture decrease due to urbanization was more sensitive in the drought year (2001) than in the flood year (2003), We expect that the results of this research can contribute to providing useful information for managing urban rivers considering river restoration and flood control.

• 한국농공학회논문집
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• 제65권1호
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• pp.73-81
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• 2023

To understand salinity status of fresh water and paddy soils and the susceptibility of rice to salinity stress of Gunnae reclaimed tidelands, salinity monitoring was conducted in rainy and dry seasons. For fresh water, a high salinity was observed at the sampling location near the sluice gate and decreased with distance from the gate. This spatial pattern of fresh water salinity indicates the necessity of spatial distribution of salinity in the assessment of salinity status of fresh water. Interestingly, there was significant correlation between rainfall amount and salinity, implying that salinity of fresh water varies with rainfall and thus it may be possible to predict salinity of water using rainfall. Soil salinity also higher near the gate, reflecting the influence of high saline water. In addition, the groundwater salinity also high to threat rice growth. Though soil salinity status indicated low possibility of sodium injury, there was changes in soil salinity status during the course of rice growth, suggesting that more intensive monitoring of soil salinity may be necessary for soil salinity assessment. Our study suggests the necessity of intensive salinity monitoring to understand the spatio-temporal variations of salinity of water and soil of reclaimed tideland areas.

• 한국산림과학회지
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• 제96권4호
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• pp.438-447
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• 2007

이 연구의 목적은 송이산 소나무림생태계의 구조와 기능, 그리고 토양 수분동태를 이해하는 것이다. 연구는 충북 괴산군 칠성면 속리산국립공원내 쌍곡의 송이산 소나무림에서, 생태계 구조에 속하는 식생구성 및 엽면적지수 그리고 기능에 속하는 광합성, 증산, 목부수분포텐셜과 토양수분변동을 측정분석하였다. 송이산의 수직적 구조로써 주요 상층식생은 소나무였고, 중층은 신갈나무, 하층은 진달래, 철쭉, 신갈나무, 쇠물푸레나무였다. 송이산의 엽면적지수는, 6월~9월에 3.8, 10월에 2.6, 11월~4월에는 2.1로 연중 변하였다. 수목들의 광합성은 8월말에 $6.0{\sim}7.0{\mu}mol\;CO_2/m^2/s$였으나, 10월 말경에는 소나무 $4.0{\mu}mol\;CO_2/m^2/s$, 신갈나무 $2.0{\mu}mol\;CO_2/m^2/s$, 철쭉은 마이너스 값이었고, 쇠물푸레나무는 낙엽되었다. 수목들의 증산량은 8월말경에 $2.5{\sim}3.5mmol\;H_2O/m^2/s$, 10월 중순경에는 약 $1.0 mmol\;H_2O/m^2/s$로 감소하였다. 신갈나무는 다른 활엽수보다 늦게까지 광합성과 증산작용을 하였다. 각 수종의 목부수분포텐셜은 소나무가 -10~ -22 bars, 진달래와 철쭉, 신갈나무, 쇠물푸레나무는 -5~-12 bars의 범위로 변화하였는데, 8월 말경이 -12 bars로 가장 낮았고, 10월 중순경에 -3 bars 정도였다. 송이산의 토양수분은 지형과 관련이 깊었다. 수분함량은 산능선부에서 7~11%, 중간인 산복에서 8~15%, 산록은 11~19%의 범위였다. 송이균환내부의 온도는 비균환보다 약 0.2~0.4 높은 경향이었고 송이원기 형성온도인 $19.0^{\circ}C$는 9월 중순경에 도달한 것으로 추정되었다. 송이균환의 수분은 비균환보다 약 0.5~2.0% 낮았다. 이것은 송이균환이 대사작용을 하면서 열이 발생하고 수분을 소비하고 있음을 나타낸다. 송이 발생에는 생태계의 구조와 기능이 복합적으로 관여하므로 이들의 관계에 대한 연구가 더욱 필요하다고 생각한다.

• 한국지반환경공학회 논문집
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• 제11권5호
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• pp.53-60
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• 2010

불포화토의 역학적 성질을 규명하기 위한 가장 기본적인 요소인 함수특성곡선을 연구하기 위하여 대구 팔공산 지역의 화강풍화토를 대상으로 함수특성곡선시험을 수행하였다. 기존의 함수특성곡선 실험은 상재하중과 체적변형의 고려없이 실시하였지만, 본실험은 두요소를 고려하기 위하여 기존의 실험장비인 압력판 추출기를 개량하여 함수특성곡선 실험을 실시하였다. 시험과정에 있어 상재하중은 0, 25, 50, 75, 100kPa을 가하였으며, 체적변형은 각 단계마다 측정하였다. 본 실험의 시료를 통한 함수특성곡선 실험 결과는 상재하중의 증가에 따라 동일한 모관흡수력에서 낮은 체적함수비를 가졌으며, 공기함입치는 증가하였다. 또한 전이영역 구간의 기울기는 감소하는 결과를 나타내었으며 이력현상은 줄어드는 결과를 보였다. 포화도는 상재하중의 증가에 따라 동일한 흡수력에서 큰 값을 나타내었으며 건조과정보다는 습윤과정이 큰 값을 나타내었다. 체적변화를 고려한 함수특성곡선은 미고려한 함수특성곡선보다 미세하게 큰 값을 나타낸다. 본 실험의 실측치와 Fredlund와 Xing(1994)의 이론식은 잘 부합하는 결과를 나타내었으며, 상수값 a, n, m값은 상재하중에 따라 기존의 연구결과와 비슷한 양상을 보였다.

• Journal of Applied Biological Chemistry
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• 제43권3호
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• pp.170-175
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• 2000

A pot-lysimeter experiment was conducted with 3-year-old 'Tsugaru' apple (Malus domestica Borkh) trees to examine the changes in oxygen diffusion rate (ODR) with lateral flow velocity of water through soil. The influence of lateral water flow velocity on water relations and elemental content in leaf, and sap temperature distribution patterns of the xylem of trees were also determined. Trees were grown under four soil water regimes: (1) fast laterally flowing (FWT, $2.50{\times}10^{-4}cm\;s^{-1}$), (2) slow laterally flowing (SWT, $0.25{\times}10^{-4}cm\;s^{-1}$), and (3) stagnant water table (WLT) at 60-cm, and (4) drip-irrigation at -40 kPa of soil matric potential as a control. The rate of $O_2$ diffusion converged near $2{\times}10^{-3}g\;m^{-2}\;min^{-1}$ for FWT and control soils, but decreased below $1{\times}10^{-3}g\;m^{-2}\;min^{-1}$ 40 days after treatment (DAT) for WLT soils. For SWT soils, however, the ODR at 15 cm below the soil surface was similar to that of control, but at 45 cm below the soil surface, ODR was similar to that of the WLT treatment. Leaf water potential of FWT and SWT plants was similar to that of control plants, but the values for SWT plants declined by 98 DAT. Leaf water potential of WLT plants decreased from -1.86 MPa (9 DAT) to -2.41 MPa (59 DAT) and finally down to -2.70 MPa. The sap temperature measured at 1100-hr was lowest at top and highest at bottom for FWT and control plants, but this pattern of SWT and WLT plants was disturbed from 29 DAT. However, for SWT plants, such thermal disturbance of sap temperature disappeared from 63 DAT.

• Geomechanics and Engineering
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• 제22권3호
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• pp.245-254
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• 2020

The interaction between the frozen soil and building structures deteriorates with the increasing temperature. A nuclear magnetic resonance (NMR) stratification test was conducted with respect to the unfrozen water content on the interface and a shear test was conducted on the frozen soil-structure interface to explore the shear characteristics of the frozen soil-structure interface and its failure mechanism during the thawing process. The test results showed that the unfrozen water at the interface during the thawing process can be clearly distributed in three stages, i.e., freezing, phase transition, and thawing, and that the shear strength of the interface decreases as the unfrozen water content increases. The internal friction angle and cohesive force display a change law of "as one falls, the other rises," and the minimum internal friction angle and maximum cohesive force can be observed at -1℃. In addition, the change characteristics of the interface strength parameters during the freezing process were compared, and the differences between the interface shear characteristics and failure mechanisms during the frozen soil-structure interface freezing-thawing process were discussed. The shear strength parameters of the interface was subjected to different changes during the freezing-thawing process because of the different interaction mechanisms of the molecular structures of ice and water in case of the ice-water phase transition of the test sample during the freezing-thawing process.

• 한국의류학회지
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• 제41권2호
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• pp.341-351
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• 2017

This study evaluates a cleaning method to maintain and minimize the change of blood soil for the selective removal of stains from textiles with historical significance and special meaning. Cotton and silk fabrics were soiled with blood, aged artificially and then washed by wet cleaning or dry cleaning (water, nonionic surfactant; Triton, natural surfactant; saponin, organic solvent; n-Decane). The washed fabrics were stored at room temperature for four years. The change of the blood soil was evaluated by SEM, weight, thickness, and color differences. Subsequently, the shape and the amount of blood adsorption on the fabric varied depending on fiber type and fabric structure characteristics; in addition, long term storage affected changes to blood soil. It was difficult to remove artificially aged blood soil from fabrics by wet or dry cleaning. However, the changes of the blood soil by these cleanings can be explained by the changes on SEM, weight, thickness and fabric color. The changes (especially color) showed over time. Wet cleaning showed that the changes of those factors were slightly lower than those by dry cleaning.

• 생물환경조절학회지
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• 제12권1호
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• pp.38-44
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• 2003

플라스틱 하우스 내에서 토성과 재배조건을 달리하여 라이시메터를 이용한 용적법으로 고추의 증발산량을 구하고자 하였다. 멀칭과 사질 또는 점질양토는 무멀칭과 모래에 비하여 고추의 증산량이 높았으며, 고추의 생장과 수량을 증가시켰다. 그히고 총 관수량의 약53%∼72%가 고추의 증산에 소모되었고, 증발산량의 약 91%∼94%가 증산에 이용되었으며 증발량은 시기에 따라 크게 변하지 않았으나 생장 초기에 증산량보다 높은 편이었다. 고추의 전 생장기간 동안 증발산량은 기상조건과 생장량에 따라 다르지만, 점질양토에서 337.7∼774.3 mm, 사질양토에서 910.6 mm, 모래에서 253.1 m의 증산량을 보였다.

• 한국지반공학회논문집
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• 제26권4호
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• pp.15-26
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• 2010

폐타이어 파우더 혼합에 따른 동상억제 메커니즘을 규명하기 위해, 부동수, 열전도율, 동상실험 등 3종류의 실내실험을 수행하였다. 본 연구에서는 폐타이어 혼합에 따른 투수계수 변화에 주목하여 먼저 마동결토의 불포화 투수계수를 계산하였고 ice-impeding factor, 혼합토내 토립자와 폐타이어 단면적을 고려하여 동결토frozen fringe내의 온도변화에 따른 투수계수 특성을 분석하였다. 그 결과 흡수속도와 투수계수 사이에는 비례관계가 존재함을 확인하였고, 동상성 저하의 주된 원인은 폐타이어 파우더 혼합에 따른 부동수분량과 투수계수의 감소임을 알 수 있었다. 또한 폐타이어 파우더 혼합토 구성성분의 체적비를 이용하여 흙과 폐타이어 간극내의 수분량을 정량적으로 산출하였다.