• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.168-172
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• 1996

The soil moisture content and its relation to plants may be important in determining the crop growth and yield. The present study was undertaken to evaluate the leaf water potential and photosynthetic activity in soybean plants as affected by the timing of soil water stress. The soybean variety, 'Tachinagaha', was grown in a pot. The 15 day-old seedlings were subject to the three levels of soil moisture content(25, 40 and 55%) for 25 days. Then the treated soybean plants were placed again at the level of 25% soil moisture content for 25 days, and were compared with the control which was well-watered at 40% level for whole growth period. Soybean plants grown under continuous drought showed higher apparent photosynthetic rate(AP) than those under well-watering /drought in the first /second water treatment, suggesting that AP was adjusted after previous acclimation to drought. Over a wide range of photosynthetic photon flux densities(PPFD), drought or excessive water stress resulted in the decrease in AP when compared with the control. AP and stomatal conductance were decreased in soybean plants subject to water deficit stress, suggesting that AP and stomatal conductance were more sensitive to drought than excessive water stress.

• Journal of Korea Water Resources Association
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• v.57 no.1
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• pp.21-33
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• 2024

Recently, the patterns of climate change-induced disasters have become more diverse and extensive. To develop an effective flood control plan, Korea has incorporated the concept of Potential Flood Damage (PFD) into the Long-Term Comprehensive Water Resources Plan to assess flood risk. However, concerns regarding the PFD have prompted numerous studies. Previous research primarily focused on modifying and augmenting the PFD index or introducing new indices. This study aims to enhance the existing flood control safety evaluation method by utilizing a flood risk map that incorporates risk indices, specifically focusing on the Yeong-Seomjin river basin. The study introduces three main evaluation approaches: risk and potential analysis, PFD and flood management level analysis, and flood control safety evaluation. The proposed improved evaluation method is expected to be instrumental in evaluating various flood control safety measures and formulating flood control plans.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5D
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• pp.533-540
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• 2010

Dam is very important facility in water supply and flood control. Therefore study needs to analyze reservoir capacity accurately to manage Dam efficiently. This study compared time series reservoir capacity using multi-dimensional spatial information to Chungju Dam reservoir and major conclusions are as follows. First, LiDAR and multi beam echo sounder survey were carried out in land zone and water zone of Dam reservoir area. And calibration process was performed to enhance the accuracy of survey data and it could be constructed that multi dimensional spatial information which was clearly satisfied with the standard of tolerance error by validation with ground control points. Reservoir capacity by water level was calculated using triangle irregular network from detailed topographic data that was constructed by linked with airborne LiDAR and multi beam echo sounder data, and curve equation of reservoir capacity was developed through regression analysis in 2008. In the comparison of the reservoir capacity of 2008 with those of 1986 and 1996, the higher water level goes, total reservoir capacity of 2008 showed decrease because of the increase of sediment in reservoir. Also, erosion and sediment area could be analyzed through calculating the reservoir capacity by the range of water level. Especially the range of water level as 130.0~135.0 which is the upper part of average water level, showed the highest erosion characteristics during 1986~2008 and 1996~2008 and it is considered that the erosion of reservoir slant by heavy rainfall is major reason.

• Journal of Biosystems Engineering
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• v.15 no.4
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• pp.328-338
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• 1990

The objective of this study was to develop automatic systems of nutrient solution management for optimal nutrient solution environment and labor saving in water culture which enables factory crop production. In this study, an automatic control system and its driving program are developed to prepare, supply, and recover nutrient solution and to keep the optimal solution concentration level using microcomputers. Based on this study, the following conclusions are obtained: 1. The concentration measured by the system using oscillating circuit designed and built in this study, gave good agreements with the actual nutrient solution. 2. In water culture, the period of 12 hours for measuring concentration, pH, and temperature of the nutrient solution was optimum. Addition of control solution due to the decrease of the nutrient solution concentration is required in every 3 to 5 days. 3. It is estimated that the period of the whole solution change is 15 days, however, further research is needed to assure it. In addition, this period must be shortened in the future. 4. Both the hardware and software of the developed optimal nutrient solution control system in the water culture are working very well, however, it is necessary to develop a more economical one-chip micro controller to substitute for the microcomputer.

• The Journal of Society for e-Business Studies
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• v.20 no.4
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• pp.1-17
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• 2015

A river water level monitoring system which prevents salt water damages and effectively excludes floods has been developed to contribute efficient operation of Nakdong river estuary barrage. The system can be used for monitoring upstream conditions more quickly and do appropriate responses over changes. Telemetry and telecontrols using PLCs have been built at the three sites that directly influence on the operation of barrage gates, and are linked to Nakdong river estuary barrage's IOS (Integrated Operation System) through public communication networks. By using PLC, the system can achieve even higher reliability and versatility than before as well as easy management. By power control devices, we can remotely control the power of PLCs to treat the minor troubles instantly without going on-sites. The power control devices also save data in preparation for the cases of communication failures. The system uses ADSL (FTTH) as a main network between SCADA server and PLCs, and CDMA (M2M) as a secondary network. In order to compensate security vulnerabilities of public communication network, we have installed the VPNs for secure communication between center and the observation stations, just like a dedicated network. Generally, river water level observations have been used custom-manufactured remote terminals to suit their special goals. However, in this case, we have established a system with open architecture considering the interface between different systems, the ease of use and maintenance, security, price, etc.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.3
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• pp.79-95
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• 2015

To suggest ecological management plans for invasion of Salix gracilistyla, stepwise environmental sieve of seed dispersal, germination, seedling and juvenile stages were investigated. About 84% of total seeds were released between May 6 and 10. Germination rates significantly declined with decrease of light intensity from 100% to 30% and 0% (p<.001), but above 60% of seeds germinated in all treatments. Difference of germination rates with 0 and 2cm water level was not significant (p = .571). With increase of elapsed time after seed dispersal, germination rates significantly decreased (p<.001), and seed viability was lost within 16 days. Considering both germination rate of seed and survival rate of seedling, survival rate of all dispersed seeds was only 5% when 8 days passed after seed dispersal. All 22-day-old seedlings (height: 1cm) died under flooding of twice level as its height. With decrease of light intensity from 100% to 30%, survival rates of seedling decreased from 90% to 33% (p<.001). In the case of 45-day-old juvenile (height: 20cm), survival rate was 70% under the water level same as its height. There was significant interactive effect of water level and light intensity on the growth of juvenile (height: p<.001, dry weight: p<.01), and survival rate of juvenile was 10% under +20cm-water level and 30%-light intensity condition. The following management plans for invasion of S. gracilistyla are recommended from these results. (1) Dry condition should be maintained at fringe of wetlands for about two weeks at seed dispersal and germination stage (early May~mid May). (2) Water level should be raised to about 5cm at fringe of wetlands for about two weeks at seedling stage (mid May~early June). (3) Water level should be raised to over 20cm at fringe of wetlands for a long time at juvenile stage. Planting trees for shading can raise management effectiveness (mid June~). (4) As water level manipulating is performed as fast as possible for controlling seedling and juvenile, management become easier and more effective.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.255-277
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• 1998

The aim of this experiment was to investigate the effects of Aqua-Acupuncture of Yukmijiwangtang(六味地黃湯) and Palmijihwang-tang(八味地黃湯) water extracts applied at the meridian points BL 23(賢兪) and GV 4(命門) to test the renal function in normal rats. The results obtained were as follows; 1. Among the effects of Aqua-Acupuncture of Yukmijihwangtang water extract at the merdian point BL 23 group, there were significant changes in water balance and urine volume over a 1 week period; Both decreasing and decreasing trends were exihibited. Urinary excretion of sodium and free water clearance changed significantly over a 2 week period; Both decreasing and increasing trends were exihibited, Urinary excretion of potassium, chloride and creatinine, plasma renin activity, plasma levels of aldosterone and atrial natriuretic peptide showed no significant differences compared to the contral group. 2. Among the effects of Aqua-Acupuncture of Palmljihwangtang water extract at the merdian point BL 23 group, there were significant changes in water balance and free water clearance over a 2 week period; a decreasing trend. Urinary excretion of creatinine changed significantly over a 2 week period; an increasing trend. Urinary excretion of chloride changed significantly over 1 week period; an increasing trend. The plasma levels of atrial natriuretic peptide changed significantly over 1 and 2 week period; an increasing trend. Urine volume, urinary excretion of sodium and pottasium, plasma renin activity and plasma level of aldosterone showed no significant differences compared to the control group. 3. Among the effects of Aqua-Acupuncture of Yukmijihwangtang water extract at the meridian point GV 4 group, there was significant decrease in water balance over a 2 week period; there was significant decrease in urine volwne and urinary excretion of sodium and creatinine over a 1 week period, followed by an increasing trend after 2 weeks. Urinary excretion of free water clearance demonstrated significant changes over both 1 and 2 week period; both increasing and decreasing trends were exihibited. Urinary excretion of chloride and plasma levels of aldosterone increased significantly over 1 and 2 week period. Plasma levels of atrial natriuretic peptide also decreased significantly. Plasma renin activity showed no significant differences compared to the control group. 4. Among the effects of Aqua-Acupuncture of Palmijihwangtang water extract at the meridian point GV 4 group, water balance and urinary excretion of chloride, plasma levels of aldosterone decreased significantly over both 1 and 2 week period. Urine volume and urinary excretion of pottasium decreased significantly. Urinary excretion of creatinine and urinary excretion of sodium changed significantly over both 1 and 2 week period. Urinary excretion of free water clearance, plasma renin activity and plasma level of atrial natriuretic peptide showed no significant differences compared to the control group. Seeing these results, I come to know that the effects Aqua-Acupuncture of Yukmijihwangtang and Palmijihwangtang water extracts at the meridian point BL 23 and GV 4 have affected the renal function differently. Seeing the results that BL 23 is a meridian point for Aqua-Acupuncture directly related to the kidney, I think, we can use Aqua-Acupuncture of Yuk-mijihwangtang and Palmijihwangtang water extracts to prevent and to treat the diseases related to kidney.

• Korean journal of food and cookery science
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• v.20 no.1
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• pp.81-85
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• 2004

This study was conducted to investigate the antioxidant activities of clove extracts in water, methanol and ether. The clove extracts, BHA and ${\alpha}$-tocopherol were added to each oil at a level of 200 ppm. The activities of the substrate oils and controls were tested under autoxidation and thermal oxidation conditions. The degree of the effects of the antioxidant activities under autoxidation condition were in the following order; ether extract 〉 methanol extract 〉BHA 〉 ${\alpha}$-tocopherol 〉 water extract = control group. The induction periods of the control, water, methanol and ether extracts, and BHA and ${\alpha}$-tocopherol were 9.5, 9.6, 10.7 11.8, 10.4 and 9.7 days, respectively. Under thermal oxidation condition, the methanol extract showed stronger antioxidant activity than those of the water and ether extracts. The antioxidant activity of the methanol extract was attributed to ${\alpha}$-tocopherol and BHA.

• Journal of Environmental Health Sciences
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• v.16 no.1
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• pp.29-43
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• 1990

The purpose of this study is to investigate the vairous change in the toxicity of cadmium by the simultaneous administration of selenium and zinc, which have been reported to change -the toxicity of cadmium through the interaction with cadmium, to rat. For the experiment, 42 rats of Sprague-Dawley strain were used. The experimental groups were divided into 6 groups: a control group, a cadmium (100ppm) alone treatment group, a cadmium (100ppm) and zinc (100ppm) combined treatment group, and three cadmium (100ppm), zinc (100ppm) and selenium (1, 4, and 8ppm) combined treatment groups. The rats were allocated seven to each group and observed for seven weeks. The results of experiment are as follows: 1. The food consumptions of each group were reduced, compared with a control group, especially, in a cadmium and zinc combined treatment group and a cadmium $\cdot$ zinc and selenium(1ppm) combined treatment group to the significant level compared with a control group (p < 0.05). The water consumptions of each group were reduced to the very significant level compared with a control group (p < 0.01). The feed efficiencies of each group were lower than a control group, and among them the highest group was cadmium $\cdot$ zinc and selenium (8ppm) combined treatment group as 90% of a control group. 2. In all groups, the weight gains were highest in the second week and the total weight gains were reduced to the very significant level compared with a control group (p < 0.01). 3. In all groups, the relative weights of liver were reduced, compared with a control group, especially, a cadmium alone treatment group was reduced to the significant level (p < 0.05). The relative weight of kidney was high to the significant level in a cadmium alone treatment group (p < 0.05) compared with a control group. In all groups, the relative weights of testis were reduced, compared with a control group, but the levels were not significant. 4. The accumulation of cadmium was highest in the kidney and the order of height was in liver, testis and blood, respectively. In all groups, the amount of cadmium accumulation was high to the very significant level compared with a control group (p < 0.01). In liver, the amount of acdmium accumulation in. a cadmium alone treatment group was high to the significant level compared with a cadmium $\cdot$ zinc and selenium (8ppm) combined treatment group (p < 0.05), and in kidney, the amount of cadmium accumulation in a cadmium alone tretment group was high to the very significant level compared with the cadmium $\cdot$ zinc and selenium (4, 8ppm) combined treatment groups (p < 0.01). However, in testis, among the treatment groups the level was not significant and in blood, a cadmium alone treatment group was low to the significant level compared with the cadmium $\cdot$ zinc and selenium (4, 8ppm) combined treatment groups (p < 0.05). 5. According to the histopathological finding on the testis, some of the seminiferous tubules of a group treated with cadmium alone showed severe necrosis and atrophy. But the testis of cadmium $\cdot$ zinc and selenium (8ppm) combined treatment group was similar to that of a control group. From the results of this study, it can be concluded that the repeated simultaneous oral administration of large doses of selenium with the cadmium produces the partial amelioration of cadmium toxicity, whereas zinc does not.

• The Korean Journal of Physiology
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• v.2 no.1
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• pp.47-52
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• 1968

Twenty white rabbits anesthetized with nembutal (30 mg/kg) were employed in this experiment. Five of them served as controls; the remaining rabbits as experimental group were subjected to irreversible hemorrhagic shock. Shock was induced by bleeding the animals until mean blood pressure decreased to a level of 50-40 mmHg. This level of pressure was maintained for 3-4 hours, after which the drawn blood was reinfused. The reinfusion of blood caused the elevation of arterial pressure almost the control level for some minutes, after which a gradual and progressive decline of blood pressure became evident. This decline was thought to be the result from irreversible hemorrhagic shock. When mean blood pressure declined to less than 50 mmHg, chest was opened and samples of arterial blood and left ventricular muscle were taken. Left ventricular muscle and blood plasma were analyzed for potassium, sodium, chloride and water content. Blood glucose concentration was determined by Somogyi-Nelson's method. Extracellular and intracellular myocardial water and electrolyte content were calculated on the basis that electrolytes are distributed between plasma water and interstitial water according to Gibbs-Donnan equilibrium. In this calculation extracellular water was substituted for Na space. The findings obtained were as follows: 1. The concentration of blood glucose was 87mg% in the controls and it rose to 222 mg% in shock (P<0.01). 2. Plasma potassium elevated significantly from 3.3 mEq/l in controls to 8.0 mEq/l in shock (P<0.01), while small decreases in sodium (151-146 mEq/l) and chloride (102-96 mEq/l) were observed (P<0.3, P<0.1), 3. The changes of blood water content (83.1-84.3%) and cardiac water content (77.5-78.3 gm/100gm WT) were observed. 4. In control animals myocardial potassium levels which averaged 30.2 mEq/100 gmDT rose significantly to 40.3 mEq/100 gmDT in shock (P<0.01), while moderate decreases in sodium(16.3-14.3 mEq/100 gmDT) were observed in shock. 5. The calculated transmembrane resting potential of left ventricular muscle of control animals averaged 95 mV, while rabbits in shock averaged 77 mV. (P <0.01). The findings of this experiment do not correspond with the conclusions that myocardial depression seems to be the cause of irreversible hemorrhagic shock, because the excitability of heart muscle is elevated. From the point of view that the lowered transmembrane resting potential, the cause of death in terminal stage of irreversible hemorrhagic shock may be ventricular fibrillation. It can't be said, however, that the lowered transmembrane resting potential is responsible for the transition from reversible to irreversible hemorrhagic shock. The marked increase in blood glucose suggested that glycogenolysis in the liver is favorably active in shock.