• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.167-173
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• 1996

Laser distance meter and x-y robot employed in the extraction of three dimensional image recognition of muskmelon net and recognized the characteristics of that. All data measured transmitted to the PC/AT in the computer room and programmed with Visual Basic(Microsoft). Alteration of the concentration and application time of nutrient solution modified the net height and width of hydroponically grown muskmelon. Net height and width which are the characteristics of muskmelon depended on the concentration of nutrient solution used. Decreasing with the concentration of nutrient solution lowered the occupying ratio of net and also observed the tendency of widening of muskmelon net.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.5
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• pp.27-35
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• 2010

The characteristics of delivered nutrient loads were analyzed and the regression equations to estimate delivery ratios of nutrients (TN and TP) were developed using HSPF simulation results at six subwatersheds within the Bochung A unit watershed during 1998-2007. TN delivery ratio was higher than TP delivery ratio because significant amounts of TP was considered to be attached at soil as ${PO_4}^-$ during delivery process from discharged point of nutrient source to main stream. As a results of correlation analysis, factors related to geomorphic characteristics had not statistical correlation with TN and TP delivery ratios. TN loading rate from living and specific stream flow had statistical negative and positive correlation, respectively, with TN delivery ratio. TP loading rates from all sources and from land cover and specific stream flow had statistical negative, negative and positive correlation, respectively. The specific stream flow represents the most strong correlation with nutrient delivery ratios. The regression equations to estimate delivery ratios for TN and TP were developed by including statistical correlated factors and showed high efficiency of 0.98 and 0.95 of coefficient of determination for TN and TP, respectively.

• Journal of Environmental Impact Assessment
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• v.9 no.2
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• pp.99-107
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• 2000

In order to solve water quality problem of domestic dam reservoir, many projects have been performed in a point of view to restoration of water quality. This study was carried out to evaluate the effect of release from sediment on water quality and release characteristics. Daecheong dam reservoir was investigated for two years, from 1998 to 1999. The nutrient release rates of Daecheong reservoir is less than foreign eutrophic reservoir at anoxic condition. For the evaluation of the effect of nutrient release on water quality, internal and external loading was calculated at Daecheong reservoir. As total phosphorus loading from sediment is calculated 9.3 ton/yr and inflow loading from Daecheong reservoir watershed 118 ton/yr, internal loading shows the portion of 7.88% to external loading. At this study, because sampling point was choosed at the point where much sediment is accumulated, experimental result is more than average release rates. Because Daecheong reservoir shows complete thermal stratification and anoxic condition below 30m from water surface in summer seasons, released phosphorus from sediment can not transfer to epilimnion and eventually resettles. Therefore sediment has insignificant impacts on water quality on Daecheong dam reservoir.

• Journal of the Korean Dietetic Association
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• v.12 no.2
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• pp.146-156
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• 2006

The purpose of this study was to analyze characteristics of the obese children in depth and provide basic information for a comprehensive educational program for the obese children. Physical and biochemical characteristics, nutrient intake, and self-esteem, etc. of 16 obese elementary school children (OC) and 14 normal weight elementary school children (NWC) were examined. Self-esteem was measured using Likert-type scales with description. Plasma levels of total cholesterol, LDL-cholesterol, and glucose of OC were higher than those of NWC. Dietary intake with a lunch provided more energy and vitamin B1 in OC than in NWC. Physical appearance and athletic competence among self-esteem in OC were lower than in NWC. However, there was no significant difference in physical activity between OC and NWC. In OC, atherogenic index was positively related with waist circumference, obesity index and BMI while athletic competence self-esteem was negatively related with them. It is recommended that the children should receive the comprehensive educational program for improving children' dietary behavior and their self-esteem.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.1-8
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• 2010

To investigate the effects of sediments on the water quality of an estuary reservoir, Asan reservoir, we analyzed physical and chemical characteristics of the sediments and estimated nutrients release rate from the sediments. The sediments characterized as sandy loam are mainly composed of Nonapatite-P(64.7%) which has strong influence on the eutrophication of the reservoir by releasing from the sediments under the condition of increasing pH and anaerobic environment. High nutrient release rates was observed in April. Negative release rates in June show that there is no significant nutrient release from the sediments. The nutrient release was active at the Site B around the confluence of tributary compared to the Site A near the embankment. Based on the information of nutrient release rates and sediments surface area, daily average nutrient release rates of Asan reservoir are estimated; TN 6,609 kg/d, TP 3,877 kg/d. Since the amount of N and P released from the sediments corresponds to the 7.06% of N and 22.04% of P incoming from the watershed, it can be concluded that there is little influence of sediments on the water quality of Asan reservoir.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3345-3350
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• 2014

We investigated to assess the relationships between the major nutrients and phytoplankton dynamics during the spring season in 2010 and 2011 at 23 stations in Jinhae Bay, Korea. The bay is divided into four different zones based on pollutant sources and geographical characteristics. Nutrient limitation (>80%) was significant in Zone II, which is located in central bay and is influenced by the water well mixed from outer bay. The limited nutrient was followed in Zone III and IV that was occupying between 17% and 83%. However, the low levels are being kept below 35% in Zone I, which is characterized by the semi-enclosed eutrophic area of Masan and Haegam bays. Based on the PCA (principle component analysis) analysis, the nitrogen (N) sources in 2010 were particularly dominant and it may be due to the water mixing and wastewater formed from bottom layers and sewage. In 2011, major nutrients including nitrogen, silicon and phosphorus were dominant in the bay and are supplied by the river discharge after rainfalls with low salinity conditions. In particular, the N nutrients being supplied in 2010 are correlated with pennate diatoms Pseudo-nitzchia spp. and is not related to the phytoplankton population densities in 2011. The present study suggests that N sources play an important role in the proliferation of diatom, and the rapid nutrient uptakes by them are potential nutrient limitation factors in the bay.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1300-1305
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• 2011

The study was conducted to investigate the characteristics of flower quality and yield of gerbera 'Sunny Lemon' by mutrient solution strength and media of nutrient solution. The plant growth of 'Sunny Lemon' showed the highest values in the media of rockwool and perlite 1: peatmoss 2. Especially the yield of cut flowers for a year was more than 60 flowers and the flower longevity was over 10 days irrespective of nutrient solution concentration in the two media. There were no significant differences of plant characteristics in the nutrient concentration of 1/2 and 1 times, and the mineral nutrient contents showed similar values. Therefore, we recommended the media of perlite1: peatmoss2 with the concentration of 1/2 times for economical use. The rockwool media was not appropriate because of the weak buffer capacity like EC and pH.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.6
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• pp.1055-1061
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• 1996

This study was conducted to assess meal management and nutrient intake of 357 elderlies in Ulsan. 114 male and 243 female elderlies over 65 year old were recruited from July 5 to August 13, 1995. Questionnaires for general characteristics of the subjects(such as family size, living cost, pocket money and health condition) and for meal management were used. The levels of depression and anxiety were measured by CED-S and Spielbuger's STAI-S, respectively In addition, nutrient intakes were conducted by convenience methods. Nutrient intake of male and female showed the average daily intake of energy, Protein, vitamin A, vitamin $B_2, $ and vitamin C were lower than Korean recommended dietary allowances(RDA). But other nutrient intake were higher than RDA except that calcium intake of female was lower. Most nutrient intakes were positively correlated with family size, living cost, pocket money and health condition. Depression and anxiety scores were also negatively correlated with most of nutrient intakes. The pattern of meal management could predict nutrient intakes as expected : regularity and pleansantness of eating were positively correlated with nutrient intakes, whereas unbalanced meal and eating lonely were negatively correlated with them.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.28-33
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• 2001

Lettuces were grown hydroponically in three different nutrient solutions, normal and 30 or 50 mM $KNO_3-added$ nutrient solutions, and the electrical conductivities of the nutrient solutions were 1.0, 4.5, and 6.5 dS/m, respectively. Lettuces grown in the $KNO_3-added$ nutrient solutions showed a decrease in the germination ratio and the lower indices of growth, such as plant height, stem diameter, leaf length, and leaf width. Microsomes were prepared from the roots of lettuce and characteristics of microsomal ATPases were investigated. The activities of microsomal ATPases grown in the 30 mM and 50 mM $KNO_3-added$ nutrient solutions were higher than that grown in the normal nutrient solution. The highest activities of microsomal ATPases were observed at pH 7.0 in all culture conditions. The activities of microsomal ATPases were increased in a reaction buffer solution containing high concentration of $K^+$, whereas they were decreased in a reaction buffer containing $Na^+$. The stimulating effect of $K^+$ in the reaction buffer was greater on the microsomal ATPases of lettuces grown in the $KNO_3-added$ nutrient solutions than that grown in the normal nutrient solution. These results imply that the activities of microsomal ATPases in the root tissue are increased as increasing the $KNO_3$ concentration in the hydroponical nutrient solution.

• Journal of Bio-Environment Control
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• v.1 no.2
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• pp.123-134
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• 1992

In order to verify the usability of the greenhouse for aquaculture with nutrient culture synchronously and to obtain the fundamental data fir the establishment of efficient farming technology, the characteristics of microclimate and the growth of leafy vegetables were examined. Tilapia averaged 428.6 g grew to 784 g(1.83 times) for 147 days from May 29 to Oct. 21 and fingerlings averaged 12.9 g grew by 1.37 times for 61 days from Sep. 13 to Nov. 12. The growth of vegetables such as water dropwort, leaf lettuce, Chinese cabbage, and Welsh onion in the greenhouse was better for aquaculture with nutrient culture than for nutrient culture only. Between above two greenhouses, pH and EC of nutrient solution was same but the temperature different by about 2$^{\circ}C$. Average day temperature, relative humidity, and $CO_2$ concentration were higher by 2.9$^{\circ}C$, 6%, and 200 ppm in the greenhouse for aquaculture with nutrient culture, respectively. Net assimilation rate of vegetables in the greenhouse was a little higher for aquaculture with nutrient culture than for nutrient culture only. Therefore, provided aquaculture and nutrient culture are carried out in the same greenhouse, the saving effect of heating cost as well as the additional promotive effects of vegetable and tilapia growth can be obtained.