• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.1
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• pp.4279-4295
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• 1977

Two types of model were established in order to product the soil moisture content by which information on irrigation could be obtained. Model-I was to represent the soil moisture depletion and was established based on the concept of water balance in a given soil profile. Model-II was a mathematical model derived from the analysis of soil moisture variation curves which were drawn from the observed data. In establishing the Model-I, the method and procedure to estimate parameters for the determination of the variables such as evapotranspirations, effective rainfalls, and drainage amounts were discussed. Empirical equations representing soil moisture variation curves were derived from the observed data as the Model-II. The procedure for forecasting timing and amounts of irrigation under the given soil moisture content was discussed. The established models were checked by comparing the observed data with those predicted by the model. Obtained results are summarized as follows: 1. As a water balance model of a given soil profile, the soil moisture depletion D, could be represented as the equation(2). 2. Among the various empirical formulae for potential evapotranspiration (Etp), Penman's formula was best fit to the data observed with the evaporation pans and tanks in Suweon area. High degree of positive correlation between Penman's predicted data and observed data with a large evaporation pan was confirmed. and the regression enquation was Y=0.7436X+17.2918, where Y represents evaporation rate from large evaporation pan, in mm/10days, and X represents potential evapotranspiration rate estimated by use of Penman's formula. 3. Evapotranspiration, Et, could be estimated from the potential evapotranspiration, Etp, by introducing the consumptive use coefficient, Kc, which was repre sensed by the following relationship: Kc=Kco$.$Ka＋Ks‥‥‥(Eq. 6) where Kco : crop coefficient Ka : coefficient depending on the soil moisture content Ks : correction coefficient a. Crop coefficient. Kco. Crop coefficients of barley, bean, and wheat for each growth stage were found to be dependent on the crop. b. Coefficient depending on the soil moisture content, Ka. The values of Ka for clay loam, sandy loam, and loamy sand revealed a similar tendency to those of Pierce type. c. Correction coefficent, Ks. Following relationships were established to estimate Ks values: Ks=Kc-Kco$.$Ka, where Ks=0 if Kc,=Kco$.$K0$\geq$1.0, otherwise Ks=1-Kco$.$Ka 4. Effective rainfall, Re, was estimated by using following relationships : Re=D, if R-D$\geq$0, otherwise, Re=R 5. The difference between rainfall, R, and the soil moisture depletion D, was taken as drainage amount, Wd. {{{{D= SUM from { {i }=1} to n (Et-Re-I+Wd)}}}} if Wd=0, otherwise, {{{{D= SUM from { {i }=tf} to n (Et-Re-I+Wd)}}}} where tf=2∼3 days. 6. The curves and their corresponding empirical equations for the variation of soil moisture depending on the soil types, soil depths are shown on Fig. 8 (a,b.c,d). The general mathematical model on soil moisture variation depending on seasons, weather, and soil types were as follow: {{{{SMC= SUM ( { C}_{i }Exp( { - lambda }_{i } { t}_{i } )+ { Re}_{i } - { Excess}_{i } )}}}} where SMC : soil moisture content C : constant depending on an initial soil moisture content $\lambda$ : constant depending on season t : time Re : effective rainfall Excess : drainage and excess soil moisture other than drainage. The values of $\lambda$ are shown on Table 1. 7. The timing and amount of irrigation could be predicted by the equation (9-a) and (9-b,c), respectively. 8. Under the given conditions, the model for scheduling irrigation was completed. Fig. 9 show computer flow charts of the model. a. To estimate a potential evapotranspiration, Penman's equation was used if a complete observed meteorological data were available, and Jensen-Haise's equation was used if a forecasted meteorological data were available, However none of the observed or forecasted data were available, the equation (15) was used. b. As an input time data, a crop carlender was used, which was made based on the time when the growth stage of the crop shows it's maximum effective leaf coverage. 9. For the purpose of validation of the models, observed data of soil moiture content under various conditions from May, 1975 to July, 1975 were compared to the data predicted by Model-I and Model-II. Model-I shows the relative error of 4.6 to 14.3 percent which is an acceptable range of error in view of engineering purpose. Model-II shows 3 to 16.7 percent of relative error which is a little larger than the one from the Model-I. 10. Comparing two models, the followings are concluded: Model-I established on the theoretical background can predict with a satisfiable reliability far practical use provided that forecasted meteorological data are available. On the other hand, Model-II was superior to Model-I in it's simplicity, but it needs long period and wide scope of observed data to predict acceptable soil moisture content. Further studies are needed on the Model-II to make it acceptable in practical use.

• Development and Reproduction
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• v.11 no.3
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• pp.167-177
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• 2007

In the present study, we isolated three human adult stem cells including adipose tissue-derived stem cells(HAD), umbilical cord-derived stem cells(HUC), and amnion-derived stem cells(HAM) and analysed their characteristics. And we examined whether HAD could be used as therapeutical cells for the heart diseases. Both HAM and HUC appeared very similar morphology but HAD was different. Doubling time of HUC was most fast, but total doubling numbers of HUC was same with HAM. Total doubling numbers of HAD was much more than others. Expression patterns of genes and proteins of three human adult stem cells were very similar. Also they were differentiated into adipocytes, osteocytes, and chondrocytes. In addition, they expressed many cardiomyocyte-related genes. But expression pattern of genes is a little different. When HAD were cultivated in the presence or absence of various combinations of BMP and FGF after 5-azacytidine expose for 24 h, expression of Cmlc-1, and ${\alpha}1c$ genes was significantly increased. However, expression of troponin T, troponin I and Kv4.3 genes was not changed. Based on these observations, it is suggested that HAD, HUC, and HAM might be used as potentially therapeutical cells for clinical application.

• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.157-163
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• 2012

BACKGROUND: For the safety of imported agricultural products, the study was conducted to develop the analytical method of unregistered pesticides in domestic. The analytical method of 6 pesticides, chlorthal-dimethyl, clomeprop, diflufenican, hexachlorobenzene, picolinafen, and propyzamide, for a fast multi-residue analysis were established for two different type crops, orange and brown rice by GC-ECD and confirmed by mass spectrometry. METHODS AND RESULTS: The analytical method was evaluated to limit of quantification, linearity and recoveries. The crop samples were extracted with acetonitrile and performed cleanup by liquid-liquid partition and Florisil SPE to remove co-extracted matrix. The extracted samples were analyzed by GC-ECD with good sensitivity and selectivity of the method. The limits of quantification (LOQ) range of the method with S/N ratio of 10 was 0.02~0.05 mg/kg for orange and brown rice. The linearity for targeted pesticides were $R^2$ >0.999 at the levels ranged from 0.05 to 10.0 mg/kg. The average recoveries ranged from 74.4% to 110.3% with the percentage of coefficient variation in the range 0.2~8.8% at two different spiking levels (0.02 mg/kg and 0.2 mg/kg, 0.05 mg/kg and 0.5 mg/kg) in brown rice. And the average recoveries ranged from 77.8% to 118.4% with the percentage of coefficient variation in the range 0.2~6.6% at two different spiking levels (0.02 mg/kg and 0.2 mg/kg, 0.05 mg/kg and 0.5 mg/kg) in orange. Final determination was by gas chromatography/mass spectrometry/selected ion monitoring (GC/MS/SIM) to identify the targeted pesticides. CONCLUSION: As a result, this developed analytical method can be used as an official method for imported agricultural products.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.664-671
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• 2019

This study was conducted to investigate the environmental impact of the construction of the Yeongju Dam, located near the upper stream of the Nakdong River, on benthic macroinvertebrates. The investigation was conducted four times from 2015 to 2016 and the composition of the benthic macroinvertebrate fauna from the four surveyed sites was compared. After the dam construction, the number of benthic macroinvertebrate species decreased and the species composition ratio of the E.P.T taxa(Ephemeroptera, Plecoptera, and Trichoptera) decreased, which favored the previous environment and the large riverbed structure. However, the species composition ratio of the O.C.H taxa (Odonata, Coleoptera, and Hemiptera), which favored the reservoir environment, increased. For the pattern of changes in the functional habitat groups, the proportion of 'Clinger(CL)' taxa decreased and the 'Burrower(BU), Climber(CB), Sprawler(SP), Swimmer(SW)' taxa increased in all surveys after the dam construction. A cluster stability comparison showed that the 'Stability Group II' species of St.2 and St.3 showed a drastic decrease. The average Benthic Macroinvertebrate Index(BMI) of all the survey sites in 2016 was lower than that in 2015. This research confirmed the temporal and spatial changes in the habitat type and community structure of the benthic macroinvertebrates resulting from the dam construction.

• Korean Journal of Food Science and Technology
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• v.46 no.6
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• pp.750-756
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• 2014

This study was performed to understand the effect of cultivation periods on the physicochemical characteristics of the starch of five sweetpotato cultivars, cultivated in Muan, Korea. Starch, protein, and ash contents increased with increased cultivation period, whereas amylose content decreased. Rapid viscosity analysis showed that the pasting temperature, peak viscosity, breakdown, setback and final viscosity increased with increased cultivation period. However, trough and final viscosity decreased. Although the onset temperature and peak temperature values increased, the conclusion temperature did not show any consistent patterns by differential scanning calorimetry. X-ray diffraction showed that the starch samples had C-type crystallinity irrespective of the cultivation period and cultivar. The starch granules were dominantly round and oval, or polygonal irrespective the cultivation period. The bigger the particle size was, the longer the cultivation period was.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.2
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• pp.141-149
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• 2004

The aim of this study was to test the validity of the hypothesis that the karyotypes of four species of Lepilemuridae were formed spontaneously from their ancestral hybrid karyotype. Hypothetical ancestral haploid Karyotype of Lepilemuridae is composed of 18 autosomes and X chromosomes. Lepilemur mustelinus karyotype has four tandem fused chromosomes and one Robertsonian translocated chromosome pairs. Lepilemur septentrionalis septentrionalis karyotype has only two pairs of translocated chromosomes. We reconstruct and suggest ancestral karyotype of LMU(ancLMU) and LSS(ancLSS), from which all four studied species were derived. Hybrids of ancLMU and ancLSS were formed and produce differently fused equilibrated gametes via circular form arrangement during gametogenesis. Five unit of trivalent homologous chromosome pairs were engaged in a circular form to give new gamete corresponding to the karyotype of L. dorsalis, orientation of one unit of trivalent was inversed in the circle to gave new gamete corresponding to the karyotype of L. leucopus. Seven homologous chromosome pairs were engaged in circular form to give haploid karyotype of Lepilemur ruficaudatus. Only one homologous chromosome pair is dissociated and the other chromosome pairs rearranged in the circle to form haploid karyotype of Lepilemur edwardsi. The new gametes could be produced from these circular forms. When the new gamete fertilized with the same type of gamete, The new homozygote is produced as existing L. dorsalis, L. leucopus, L. edwardsi and L. ruficaudatus. These results support the theory that new species could be formed in hybrid population through activated chromosome fusion, chromosome rearrangement in circular from at zygotene stage and production of equilibrated gametes to form homozygote new species.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.336-344
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• 2015

BACKGROUND: This study was carried out to collect occurrence data on aluminum in 12 type agricultural products and assess dietary exposure risk to the Korean population health for aluminum concentration in agricultural products.METHODS AND RESULTS: Aluminum analysis samples were performed using microwave device and Inductively Coupled Plasma Optical Emission Spectrometer. The LOD(Limit of Detection) for aluminum was 0.851 μg/kg, while the LOQ(Limit of Quantitation) was 2.838 μg/kg and recovery was 97.6% for aluminum. The average levels of aluminum in mg/kg were 0.526 for rice, 0.546 for Korean cabbage, 1.316 for corn, 6.207 for soybean, 0.549 for sweet potato, 0.257 for potato, 6.963 for spinach, 1.213 for carrot, 0.524 for garlic, 0.950 for radish, 1.015 for leek, and 3.511 for Welsh onion. The dietary exposures of aluminum through usual intake were polished rice 89.31 μg/day, Korean cabbage 33.14 μg/day, corn 0.66 μg/day, soybean 3.72 μg/day, sweet potato 6.86 μg/day, potato 4.96 μg/day, spinach 45.96 μg/day, carrot 6.79 μg/day, garlic 2.36 μ g/day, radish 7.32 μg/day, leek 2.23 μg/day and Welsh onion 43.89 μg/day, taking 0.57%, 0.21%, 0.00%, 0.02%, 0.04%, 0.03%, 0.04%, 0.04%, 0.02%, 0.05%, 0.01% and 0.28% of PTWI(2 mg/kg b.w./week), respectively.CONCLUSION: The levels of overall dietary exposure to aluminum for Korean population through intake of agricultural product was far below the recommended JECFA level, indicating of least possibility of risk.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.450-461
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• 2006

In this study, sorption kinetics of lead (Pb) and cadmium (Cd) onto coastal sediments were investigated at pH 5.5 using laboratory batch adsorbers. Four different models: one-site mass transfer model (OSMTM), pseudo-first-order kinetic model (PFOKM) ,pseudo-second-order kinetic model (PSOKM) and two compartment first-order kinetic model (TCFOKM) were used to analyze the sorption kinetics. As expected from the number of model parameters involved, the three-parameter TCFOKM was better than the two-parameter OSMTM, PFOKM and PSOKM in describing sorption kinetics of Pb and Cd onto sediments. Most sorption of Pb and Cd was rapidly completed within the first three hours, followed by slow sorption in the subsequent period of sorption. All models predicted that the sorbed amount at the apparent sorption ($q_{e,s}$) equilibria increased as the CEC and surface area of the sediments increased, regardless of initial spiking concentration ($C_0$) and heavy metal and the sediment type. The sorption rate constant ($k_s,\;hr^{-1}$) in OSMTM also increased as the CEC and BET surface area increased. The rate constant of pseudo-first-order sorption ($k_{p1,s},\;hr^{-1}$) in PFOKM were not correlated with sediment characteristics. The results of PSOKM analysis showed that the rate constant of pseudo-second-order sorption ($k_{p2,s},\;g\;mmol^{-1}\;hr^{-1}$) and the initial sorption rate ($v_{o,s},\;mg\;g^{-1}\;hr^{-1}$) were not correlated with sediment characteristics. The fast sorption fraction ($f_{1,s}$) in TCFOKM increased as CEC and BET surface increased regardless of initial aqueous phase concentrations. The sorption rate constant of fast fraction ($k_{1,s}=10^{0.1}-10^{1.0}\;hr^{-1}$) was much greater than that of slow sorption fraction ($k_{2,s}=10^{-2}-10^{-4}\;hr^{-1}$) respectively.

• KDI Journal of Economic Policy
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• v.34 no.2
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• pp.55-93
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• 2012

In Korea, energy policies are actualized through various energy-related plans. Recently, however, as high-ranking plans, which are very vision-oriented, continually set higher sector-by-sector goals, subordinate action plans, which require consistency, encounter distortions in their establishment process. Also, each subordinate action plan reveals limitations in terms of securing flexibility of the plan in responding to uncertainties of the future. These problems pose potential risks such as causing huge social costs. In this regard, with an aim to provide empirical evidence for discussions on improving the procedure for developing and executing Korea's energy plans, this study mainly analyzes the Basic Plan on Electricity Demand and Supply-one of the most important subordinate action plans-in order to explain the problems of the Basic Plan in a logical manner, and potential problems that could occur in the process of sustaining consistency between the Basic Plan and its higher-ranking plans. Further, this paper estimates the scale of social costs caused by those problems assuming realistic conditions. According to the result, in the case of where maximum electric power is estimated to be 7% (15%) less than the actual amount in the Basic Plan on Electricity Demand and Supply, the annual generation cost will rise by 286 billion won and (1.2 trillion won) in 2020. Such social costs are found to occur even when establishing and executing the Basic plan according to the target goal set by its higher-ranking plan, the National Energy Master Plan. In addition, when another higher-ranking GHG reduction master plan requires the electricity sector to reduce emissions by additional 5% in the GHG emissions from the right mix in electricity generation with 'zero' cost of carbon emission, the annual generation cost will rise by approximately 915 billion won in 2020. On the other hand, the analysis finds that since economic feasibility of electric powers in Korea varies significantly depending on their type, Korea is expected to face very small potential social costs caused by uncertainties over the future price of carbon dioxide in the process of establishing the Basic Plan.

• Food Science and Preservation
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• v.24 no.7
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• pp.923-933
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• 2017

This study was carried out to examine the quality characteristics of Doenjang manufactured with or without soaking Meju in brine according to salt concentrations (8 and 12%) during fermentation for 6 months. The moisture content and salinity of Doenjang fermented for 6 months were 54.9-60.3% and 7.8-12.5%, respectively. Doenjang using soaking Meju in brine had higher pH and lower titratable acidity than that using non-soaking Meju. The reducing sugar content in all samples was increased until 2 months and then decreased regardless of soaking Meju, especially that of non-soaking 8% Doenjang was the highest. The 8% low-salt Doenjang was shown the highest amino-type nitrogen content, especially the soaking Doenjang was higher than the non-soaking Doenjang. ${\alpha}$-amylase activity of all samples during fermentation were continuously decreased from 0.91-0.94 Unit/g to 0.01-0.06 Unit/g, especially the 8% soaking Doenjang was shown the highest activity after 2 months. Total bacterial count of the soaking Doenjang at the 6 months was in range of 7.8-8.0 log CFU/g and that of the non-soaking Doenjang was in range of 7.2-7.5 log CFU/g. By taste analysis, the 8% soaking Doenjang was shown the similar taste pattern with commercial Doenjang. In conclusion, the 8% low-salt Doenjang manufactured with soaking Meju in brine was a suitable concentration in order to reduce salt intake.