• 한국토양비료학회지
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• 제50권5호
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• pp.369-382
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• 2017

Accurate and optimal water supply to cereal crop is critical in growing stalks and producing maximum yields. Recently, upland crops are cultivated in paddy field soils to reduce overproduced rice in Korea. In order to increase productivity of cereal crops in paddy fields which have poor percolation and drainage properties, it is necessary to fully understand crop response to excessive soil water condition and management of soil drainage system in paddy field. The objectives of this study were to investigate effects of excessive soil water to sesame growth and to quantify stress response using groundwater levels. Two cultivars of sesame were selected to investigate; Gunbak and Areum. These sesames were planted in paddy fields located in Miryang, Gyeongnam with different soil drainage levels and drainage systems. The experiment site was divided into two plots by drainage class; very poorly and somewhat poorly drained. Two different drainage systems were applied to alleviate excessive soil water in each plot: open ditch and pipe drainage system. Soil water contents and groundwater levels were measured every hour during growing season. Pipe drainage system was significantly effective to alleviate wet injury for sesame in paddy fields. Pipe drainage system decreased average soil moisture content and groundwater level during sesame cultivation. This resulted in greater yield and lignan contetns in sesame seeds than ones from open ditch system. Comparison between two cultivars, Gunbak had greater decrease in growth and yield by excessive soil water and high groundwater level than Areum. Seed components (lignan) showed decrease in seeds as soil water increased. When soil moisture content was greater than 40%, lignan content tended to decrease than ones from less soil moisture content. Based on these results, pipe drainage system would be more effective to reduce wet injury to sesame and increase lignan component in paddy field cultivation.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.216-221
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• 2005

Many tanks such as a fresh water tank, an aft peak tank and oil tanks are arranged in the engine room and aft part areas of the ship. By added mass effect of the fluid inside the tanks, the natural frequency will be changed according to filling height of the tank. For this reason, there is possibility of occurrence of excessive vibration by resonance between natural frequencies of local structure and excitation frequencies of the propeller or main engine. Therefore, calculation of natural frequencies is required for structure for many types of tank which are contacting with water or oil to consider added mass effect for anti-resonance design at design stage. In this study, a case of structure damage on the fresh water tank for 2600 TEU container vessel is introduced. In addition, natural frequency analysis and vibration measurement have been performed to investigate vibration characteristics for excessive vibration control.

• 대한지하수환경학회지
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• 제7권3호
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• pp.133-140
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• 2000

초정지역은 세계 3대 광천수 생산지의 하나로서 지하수 이용업체들이 집중적으로 지하수 개발을 하고 있어 지하수자원의 고갈이 우려되고 있다. 본 연구에서는 초정지역의 지속적인 개발로 인해 장래 예측되는 지하수 장애에 대처하기 위해 수치모형을 이용하여 초정지역의 지하수 유통해석을 수행하였다. 해석 결과 동북쪽에 위치한 산간유역의 수위의 변화에 비하여, 하류 구릉지역에서는 양수정들을 중심으로 수위 강하가 급격하게 일어나고 있다. 이는 하류 구릉지역에 공장들이 밀집하여 있고 생활용수와 농업용수 또한 많은 양을 양수를 하는데 기인한다. 따라서 향후 지하수자원의 고갈이 우려되며, 이에 대한 대책이 심각하게 요구된다.

• 한국물환경학회지
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• 제29권1호
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• pp.66-73
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• 2013

Total Maximum Daily Loads (TMDLs) system was introduced to manage pollution load of watershed and to improve water quality of unit watershed so that it is possible to protect dringking water soureces. Load allocation observation is the most important factor in TMDLs system. Because if load allocation is not observed, it is difficult to achieve water quality goal of unit watershed. Also it is impossible to improve water quality of the drinking water sources. Therefore it is necessary to apply some kind of sanctions (penalty) in case of excess of load allocation. The sanctions have to be, however, applied differently based on various reduction plan types, i.e., using the reduction load planed in 2nd phase, delay the completion, additional reduction in 2nd phase, error of the pollution sources, etc. Moreover, the penalty load should be properly imposed, lest it should be overburden the provence. The reduction load trade inter province must be restrictively permmitted only the same unit watershed.

• 멤브레인
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• 제30권6호
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• pp.433-442
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• 2020

본 연구에서는 수전해용 ionomer의 분자동역학 전산모사 모델 제작을 위하여, 과량의 물 분자가 존재하는 수전해 시스템의 특성을 반영한 ionomer 모델을 제작한 후, 기존 연료전지용 전해질막 전산모사 조건에 맞춰 제작한 ionomer 모델과 비교하였다. 최종적으로 얻어진 모델은 과불소계 ionomer의 중요 특징 중 하나인 명확한 상분리 및 수화채널이 관찰되었으며, 과량의 물 및 높은 운전 온도 조건에서도 물에 녹지 않고 안정된 구조를 나타내었다. 제조된 ionomer 모델에서는 과량의 물분자로 인한 이온 희석 효과로 이온 전달 성능 감소가 나타났으며, 반대로 수소 기체의 투과는 더 증가할 것으로 분석되었다. 따라서 이러한 수전해 시스템의 특성을 반영한 수전해용 ionomer 분자 구조 설계 전략이 필요하고, 분자동역학 전산모사 연구 시에도 이를 감안한 수전해용 ionomer 모델 제작이 필요하다.

• 아시안잔디학회지
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• 제23권2호
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• pp.229-240
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• 2009

여름철 고온 다습한 우리나라 기온에서 토양 온도와 수분은 잔디의 생리학적 변화를 초래하며, 특히 한지형 잔디생육은 우리나라 여름철 기후의 특이성에 많은 영향을 받는다. 본 실험은 크리핑 벤트그래스(Agrostispalustris Huds.)를 이용하여 고온의 조건에서 각기 다른 토양 수분함량 조건에서의 한지형 잔디생육을 관찰하였다. 구체적인 실험 방법으로는 수분함량과 온도에 따른 bentgrass의 생육 및 생리적 스트레스 반응을 평가하였다. 모의 USGA(United State of Golf Association) 그린 조건에서의 토양 온도 및 열 특성 실험 결과 수분이 거의 없는 건조 상태에서의 토양 온도는 $34^{\circ}C$로 발열 했을 때 토양 표면 온도가 $80^{\circ}C$까지 올라가는 것을 알 수 있었다. 반면, 과수분 조건에서 $34^{\circ}C$ 발열을 했을 때에는 건조 조건에 비해 상대적으로 $10^{\circ}C$가 낮은 것을 알 수 있었다. 실험 포장에서의 온도와 수분에 따른 열 특성 변화는 관수시기와 무관하게 처리구 모두에서 관수 후에 열전도도(thermal conductivity), 열 확산성(thermal diffusivity), 및 토양 온도가 증가하였다. 이는 수분이 공기에 비해 상대적으로 높은 열전도도를 갖기 때문으로 사료된다. 또한, 본 실험에서 관수 초기에는 과수분 조건에 비해 수분 결핍 조건에서 토양 온도의 증가를 보였으며, 시간이 지남에 따라 과수분 조건에서 더 높은 토양 온도의 증가를 확인하였다. 즉, 토양 온도는 과수분 조건에서 열전도에 의해 높아져 잔디의 생육에 영향을 미친다. 이는 잔디 표면부 온도가 높은 시각대의 과도한 관수는 여름철 잔디의 생육에 부정적 영향을 미치며, 소나기 등에 의한 일시 침수 시 지반배수의 불량은 잔디 생육에 치명적인 요인이 될 수 있다는 것을 의미한다.

• 한국작물학회지
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• 제51권1호
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• pp.26-31
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• 2006

This study was conducted to determine the optimum number of inter-rows according to distance of drainage furrow (DF) for running-off excessive-water stress (EWS) in paddy field. The most soil water potential was shown in high ridge (distance of DF by 70 cm) cultivation and the soil water potential showed increasing tendency in over four inter-rows cultivation by DF. The growth of soybean reduced by extended inter-row and its reducing level was high, especially, over four inter-rows (DF distance by 2.8 m) because of EWS. The photosynthetic rate decreased in the more extensive field by distance of DF at V5 and R2 stages, especially, in over four interrows cultivation. Also, root activity decreased at wider DF. The yield was reduced with wider distance of DF more extensively, the highest yield of 270 g per $m^2$ at the every row, but yield showed decreasing tendency at over the $4^{th}$ row (2.8 m) cultivation. Soybean cultivation in paddy field could be founded with DF of every other or $4^{th}$ row.

• 한국약용작물학회지
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• 제28권6호
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• pp.412-420
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• 2020

Background: Measurement of chlorophyll fluorescence (CF) is useful for detection the ability of plants to tolerate environmental stresses such as drought, and excessive sunlight. Cnidium officinale Makino is highly sensitive to water stress and excessive sunlight. In this study, we evaluated the effect of soil water and shade treatment on the photosynthesis and leaf temperature change of C. officinale. Methods and Results: C. officinale was cultivated under uniform irrigation for 1 week drought stress (no watering) for 6 days. A significant decrease in CF was observed on the 5th day of withholding water (approximately 6% of soil water content) regardless of shading. Notably, the Rfd_lss parameter (CF decrease rates) with and without shade treatment was reduced by 73.1% and 56.5% respectively, at 6 days compared with those at the initial stage (0 day). The patterns of the degree of CF parameters corresponded to those of the soil water content and difference between leaf temperature (Ts) and air temperature (Ta). Meanwhile, CF parameters recovered to the 3 - 4 days levels after re-watering, while the soil water potential was completely restored. The suitable soil water content for C. officinale optimal growth was between -5 kPa and -10 kPa in this experiment. Conclusions: Lack of soil water in the cultivation of C. officinale, even with shading, decreased latent heat cooling through transpiration. As a result, heat dissipation declined, and the plant was subjected to drought stress. Soil water content plays a major role in photosynthesis and leaf temperature in C. officinale.

• 한국작물학회지
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• 제42권3호
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• pp.367-372
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• 1997

토성 및 지하수위에 따른 콩 품종의 생육 및 수량반응을 알아보기 위하여 라이시미터에 식양토와 사양토를 채운 후 표면으로부터 10, 30, 50cm로 지하수위를 조절하고 전 생육기간에 걸쳐 처리하여 조사한 결과는 다음과 같다. 1. 토성에 따라 지상부 건물중과 지하부 건물중, 뿌리혹수는 유의적인 차이를 보이고 있으나 엽면적과 엽녹소함량은 차이를 보이지 않았다. 토성, 지하수위, 품종의 각 상호작용에 있어서는 개화기에 조사된 생육형질들 모두 유의적인 차이를 보였다. 2. 수량은 품종과 지하수위에 따라 유의적인 차이를 보이고 있으나 토성에 따라서는 유의적인 차이를 보이지 않았다. 3. 수량안정도 계수는 소백나물콩이 $b_i=1.09$로 지하수위 처리 조건에서 가장 수량 안정성이 높은 품종으로 나타났으며 화엄풋콩은 $b_i=0.38$로 비교적 안정성이 낮은 품종으로 나타났다. 4. 유망도지수는 초다근류계통인 nts1116이 D_i=228$로 가장 높은 값으로 조사되었으며 큰올콩은 $D_i=77$로 가장 낮은 값을 나타냈다. 5. 생육과 수량과의 다중회귀분석에 의하면 지상부 건물중과 지하부 건물중, 뿌리혹수가 수량에 영향을 미치는 주요요인으로 나타났으며 지상부 건물중과 지하부 건물중은 사양토에서, 지상부 건물중과 뿌리혹수는 식양토에서 수량에 유의적인 영향을 미쳤다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.337-337
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• 2017

Accurate and optimal water supply to cereal crop is critical in growing stalks and producing maximum yields. Excessive soil moisture may cause nutrient deficiencies and oxygen deficiency. Excessive soil water during crop growth stages results in decrease of yields. In Korea, the largest agricultural lands are paddy fields. Recently, upland crops are cultivated in paddy field soils to reduce overproduced rice in Korea. In order to success this policy, it is necessary to fully understand crop response to excessive soil moisture condition from paddy field soils. Adzuki bean is one of major legumes which provide protein in daily diet. Adzuki bean has been well know its weakness to excessive soil moisture condition, In order to obtain optimal yields of adzuki bean from paddy field cultivation, it is necessary to understand response of adzuki bean under different soil moisture conditions. This study investigated characteristics of growths, yields and response degree of water stress from adzuki bean. Three cultivars were selected for this study; Chungju, Hongeon, and Arari. All adzuki beans were cultivated in a paddy field which was divided into three sections with different soil moistures. The paddy field was located in Milyang, Gyeongsangnam during 2016. One section of the paddy field had the greatest average soil moisture content as 35.1% during adzuki bean cultivation (very poor). The second greatest soil moisture section had 32.6% (somewhat poor) and the smallest soil moisture section had 28.9% of soil moisture (somewhat well). During cultivation of three cultivar adzuki beans, soil moisture contents and groundwater levels were monitored. All the characteristics of growth and yield components were measured; height, thickness, 100 seed weights etc. Stress index values were calculated by Stress Day Index (SDI). All cultivars had the greatest yields from somewhat well section. Chungju had the greatest yields throughout all three sections compared to other cultivars. Chungju had 81% greater yield than Hongeon which had the smallest yield from somewhat well section. Arari set in middle from all sections. However there was no significant differences yields from very poor and somewhat poor sections. Leaf SPAD values tended to decrease and stable carbon isotope values increased as soil moisture increased. However, Chungju had no difference across different soil moistures in SPAD and stable carbon isotope values, while Hongeon had the greatest differences across sections. These trends followed by SDI values. Chungju had the smallest SDI values compared to other cultivars, which meant that Chungju was the strongest tolerance against excessive soil moisture than other cultivars. All three cultivars showed severe decrease of yields from very poor and somewhat poor sections. Arari and Hongeon showed great decrease from somewhat well section compared to yields from upland soil. These two cultivars may not be proper cultivating in paddy fields. In conclusion, adzuki bean is very sensitive to soil moisture condition and detailed soil managements are required to obtain optimal yields of adzuki bean from paddy field cultivation.