• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.354-374
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• 2016

This study explored spatiotemporal variability of water quality in correspondence with hydrometeorological factors in the five stations of Paldang Reservoir located in the Han River during 4 years from May 2012 to December 2015. Variability of basic water quality factors were largely related with seasonal fluctuations of hydrology. Temperature stratification occurred in the deep dam station, and prolonged hypoxia was observed during the draught year. Nitrogen nutrients were increased with decreasing inflow in which changing pattern of $NH_4$ reversed to $NO_3$ by the effect of treated wastewater effluent. Phosphorus increase was manifest during the period of high inflow or severe drought. Chl-a variation was reversely related with both flow change and AGP(algal growth potential) variations. Our study demonstrated that water quality variability in Paldang Reservoir was largely attributed to both natural and operational changes of inflow and outflow (including water intake) based on major pollution source of the treated wastewater (total amount of $472{\times}10^3m^3d^{-1}$) entering to the water system from watershed. In the process of water quality variability, meteorological (e.g., flood, typhoon, abnormal rainfall, scorching heat of summer) and hydrological factors (inflow and discharge) were likely to work dynamically with nutrients pulse, dilution, absorption, concentration and sedimentation. We underline comprehensive limnological study related to hydro-meteorolology to understand short- and long-term water quality variability in river-type large reservoir and suggest the necessity of P-free wastewater treatment for the effective measure of reducing pollution level of Paldang drinking water resource.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.137-144
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• 2015

Kyejang is a Korean traditional beverage manufactured from medicinal plants and fruits using honey, sugar, or starch in cold water. In this study, cinnamon-containing kyejang, which is a type of beverage Jang, was reproduced based on Imwonsibyukji's method published in 1827 in the Korean literature. Kyejang made by nuruk, cinnamon, and medicinal plants was prepared at various temperatures and periods. Kyejang was assayed for physiochemical properties (pH and acidity), contents of metabolites (organic acids, sugars, and amino acids), and sensory characteristics (aroma and taste). During fermentation, content of organic acids (e.g. lactic acid, acetic acid, and shikimic acid) increased, which lowered pH, increased acidity, and increased intensity of sour taste. In the case of free sugars, fructose and maltose levels decreased while glucose and mannitol levels increased during fermentation periods, and sweetness decreased. The main amino acid in kyejang was tryptophan, followed by asparagine, proline, and arginine. The sensory evaluation score of overall preference was highest for kyejang which was fermented at $20^{\circ}C$ for 3 days. The results will be provide the basic data of fermentation conditions for standardized manufacturing process of kyejang.

• Journal of Korean Society of Forest Science
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• v.12 no.1
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• pp.13-21
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• 1971

As one part of the ecological studies of Korean white pine plantation, a synecological survey was made on the undergrowth vegetation of Korean white pine plantations of different age class i.e., 5, 15, 25, 35, and 40 year age classes under which shrub and ground vegetation were distinctly different. And, the results are summarized as follows. 1. In shrub, the important species is Corylus heterophylla var. japonica and the dominant species in each age-class stand are as follows; 5 year-class ; Quercus mongolica, Lespedeza Maximowiczi. 15 year-class ; Corylus heterophylla var. japonica, Lespedeza Maximowiczi. 25 year-class ; Corylus heterophylla var. japonica. 35 year-class ; Corylus heterophylla var. japonica, Maackia amurensis. 40 year-class ; Corylus heterophylla var. japonica. 2. The higher the age class of the plantation are, the lower the height and the density of the shrub become. 3. Dominant species of ground-vegetation under the shrub of each age-class are as follows; 5 year-class ; Arundinella hirta var. cilia, Miscanthus purpurascens. 15 year-class ; Arundinella hirta var. ciliata, Potentilla Freyniana. 25 year-class ; Physematium manchuriense, Viola xanthopetala, Rubus craegifolius. 35 year-class ; Viola xanthopetala, Rubus crataegifolius. 45 year-class ; Viola xanthopetala, Rubus crataegifolius. 4. The standing crops of ground vegetation under the shrub were decreased with increasing age-class, which also caused the decreasing height and density and changing floristic composition of the shrub. 5. The ratio of the standing crop of root to the standing crop of shoot was increased as the age class increased. 6. The floristic composition of ground vegetation has shown a change from heliophyte to sciophytes on the sere.

• Journal of agriculture & life science
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• v.46 no.5
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• pp.143-152
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• 2012

This study was performed to reduce the operating cost of a greenhouse by securing electric energy required for greenhouse operation. Therefore, it experimentally reviewed the performance analysis of photovoltaic system in terms of maximum amount of generated electric power based on the amount of horizontal solar radiation during daytime. That is to say, the maximum solar radiation at 300, 400, 500, 600, 700, 800 and 900 W. $m^{-2}$, respectively. The amount of momentary electric power of the photovoltaic system at any was about 970 W and we found that the momentary efficiency of the photovoltaic system that was used for this experiment was 97%. In the case of this system, we found that electric power will be generated when amount of horizontal solar radiation is more than 200 W. $m^{-2}$, at minimum. If the amount of horizontal solar radiation is increased, the maximum power generation is also increased. At that time, the maximum efficiencies were 30, 78, 86 and 90%, respectively. However, when the amount of insolation was about 800 W. $m^{-2}$, the maximum power generation tended to be lower than 700 W. $m^{-2}$. The efficiency which caused the maximum electric power was decreased to less than 97% of the momentary generated electric power. When the total amounts of horizontal solar radiation per day were 3.24, 8.10, 10, 90, 12.70, 14.33, 19.53 and $21.48MJ{\cdot}m^{-2}$ respectively, the total amounts of power energy were 0.03, 0.40, 3.60, 4.37, 4.71, 4.70 and 4.91 kWh. And it represented that the total amounts of power energy were either decreased or increased a bit on the border between some solar radiations. The temperature at the back of the array tended to be higher than the temperature at the front but it demonstrated an increased when the amount of solar radiation increased. In the case of this system, the performance of the module in terms of degradation has not been shown yet.

• Journal of the Geological Society of Korea
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• v.54 no.5
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• pp.477-488
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• 2018

Fluid muds commonly occur in estuarine environments, but their ancient examples have rarely been studied in terms of depositional characteristics and processes. Cores of estuarine channel deposits of the Early Cretaceous McMurray Formation, Alberta, Canada show various mudstone layers that possess depositional characteristics of high clay-concentration flows. These mudstone layers are examined in detail through microscopic observation of thin sections and classified into three microfacies (<1 to 25 mm thick) on the basis of sedimentary texture and structures. Structureless mudstone (Microfacies 1) consists mainly of clay particles and contains randomly dispersed coarser grains (coarse silt to fine sand). This microfacies is interpreted as being deposited by cohesive mud flows, i.e., fluid muds, which possessed sufficient strength to support suspended coarser grains (quasi-laminar plug flow). Silt-streaked mudstone (Microfacies 2) mainly comprises mudstone with dispersed coarse grains and includes very thin, discontinuous silt streaks of coarse-silt to very-fine-sand grains. The texture similar to Microfacies 1 indicates that Microfacies 2 was also deposited by cohesive fluid muds. The silt streaks are, however, suggestive of the presence of intermittent weak turbulence under the plug (upper transitional plug flow). Heterolithic laminated mudstone (Microfacies 3) is characterized by alternation of relatively thick silt laminae and much thinner clay laminae. It is either parallel-laminated or low-angle cross-laminated, occasionally showing low-amplitude ripple forms. The heterolithic laminae are interpreted as the results of shear sorting in the basal turbulent zone under a cohesive plug. They may represent low-amplitude bed-waves formed under lower transitional plug flows. These three microfacies reflect a range of flow phases of fluid muds, which change with flow velocities and suspended mud concentrations. The results of this study provide important knowledge to recognize fluid-mud deposits in ancient sequences and to better understand depositional processes of mudstones.

• Korean Journal of Remote Sensing
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• v.14 no.1
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• pp.53-68
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• 1998

Observation of hydrometeors' behavior in the atmosphere is important to understand weather and climate. By conventional observations, we can get the distribution of water vapor at limited number of points on the earth. In this study, the precipitable water has been estimated from the split window channel data on GMS-5 based upon the technique developed by Chesters et al.(1983). To retrieve the precipitable water, water vapor absorption parameter depending on filter function of sensor has been derived using the regression analysis between the split window channel data and the radiosonde data observed at Osan, Pohang, Kwangiu and Cheju staions for 4 months. The air temperature of 700 hPa from the Global Spectral Model of Korea Meteorological Administration (GSM/KMA) has been used as mean air temperature for single layer radiation model. The retrieved precipitable water for the period from August 1996 through December 1996 are compared to radiosonde data. It is shown that the root mean square differences between radiosonde observations and the GMS-5 retrievals range from 0.65 g/$cm^2$ to 1.09 g/$cm^2$ with correlation coefficient of 0.46 on hourly basis. The monthly distribution of precipitable water from GMS-5 shows almost good representation in large scale. Precipitable water is produced 4 times a day at Korea Meteorological Administration in the form of grid point data with 0.5 degree lat./lon. resolution. The data can be used in the objective analysis for numerical weather prediction and to increase the accuracy of humidity analysis especially under clear sky condition. And also, the data is a useful complement to existing data set for climatological research. But it is necessary to get higher correlation between radiosonde observations and the GMS-5 retrievals for operational applications.

• Journal of the Korean Society of Child Welfare
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• no.56
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• pp.133-164
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• 2016

This study investigated the effect of housing poverty in childhood on adolescents' subjective well-being. Specifically, this study examined whether the major factors that have been known to affect adolescents' well-being (i.e., family relationships, peer relationships, school adjustment etc.) mediated the relationship between housing poverty and adolescents' well-being. And then this study aimed to present an empirical evidence for establishing policies against housing poverty in order to enhance adolescent's subjective happiness. Data were derived from the $1^{st}$, $4^{th}$, and $7^{th}$ surveys of the Korea Welfare Panel Study(KOWEPS), and the sample included. 512 high school children in the $7^{th}$ survey. This study utilized structural equation modeling. Housing poverty was measured by the sub-minimum standard housing condition and the household's burden of housing expenditure. Family relationship, as a mediator, was measured by parental involvement in education, parental monitoring, and family conflicts. Another mediator, school adjustment was measured by school environment and school bonding, and the last mediator, peer relationship was measured by friend attachment and peer attachment. The results showed that housing poverty had significant negative effects on the adolescents' subjective well-being. The sub-minimum standard housing condition with inadequate size and facilities negatively affected adolescents' relationships with family directly and subjective well-being indirectly. In addition, the negative family relationships due to the sub-minimum standard housing condition negatively affected adolescents' subjective well-being through school adjustment and peer relationships. The greater the proportion of income a household spends on housing expenditure, the less likely for adolescents to report positive well-being. The sub-minimum standard housing condition had indirect effects through family relationships, whereas the household's housing expenditure directly affected adolescents' subjective well-being. This study suggested the necessity of interventions to alleviate housing poverty for adolescents' families and lays the groundwork for housing poverty policies in Korea.

• The Journal of Korean Obstetrics and Gynecology
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• v.29 no.1
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• pp.14-34
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• 2016

Objectives: The objective of this study was to evaluate the effects of cytotoxicity, skin regeneration, anti-wrinkle, whitening and skin moisturizing of Oncheongeum (OCE).Methods: The cytotoxicity of OCE lyophilized aqueous extracts (yield=13.82%) was observed against human normal fibroblast cells and B16/F10 murine melanoma cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium Bromide (MTT) assay, and skin regeneration and anti-wrinkle effects were also evaluated through the assay of collagen type I synthesis compared to the transformation of the growth factor (TGF)-β1, hyaluronidase, collagenase and matrix metalloproteinase (MMP)-1 inhibitory assays compared to oleanolic acid (OA), and elastase inhibitory effects compared to phosphoramidon disodium salt (PP). In addition, OCE’s whitening effects were measured by a tyrosinase inhibitory assay and melanin formation test in B16/F10 murine melanoma cells compared to arbutin, and skin moisturizing effects were observed through a mouse skin water content test, respectively. Results: No OCE treatment-related cytotoxic effects appeared on human normal fibroblasts and B16/F10 murine melanoma cells. OCE concentration-dependently increased the collagen Type I synthesis on human normal fibroblast cells, and also effectively inhibited hyaluronidase, elastase, collagenase and MMP-1 activities. In addition, OCE inhibited melanin production of B16/F10 murine melanoma cells and activity of tyrosinase. And significant and dose-dependent increases of skin water content were detected in OCE-treated mouse skin compared to vehicle control skins. Conclusions: OCE showed favorable and sufficient effects in skin regeneration, anti-wrinkle, whitening and skin moisturizing in this experiment. But more detail mechanisms and studies on the skin protective efficiency of in vivo are needed with the screening of active biological compounds in individual OCE herbs.

• Food Science and Preservation
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• v.12 no.4
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• pp.329-335
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• 2005

Storage quality characteristics of low fat salad dressing with spirulina($0.28\%$) was evaluated. After 2 wks of storage, viscosity decreased according to the prolonged storage time. After 8 wks storage, emulsion stability decreased to $30\%$, which was $25\%$ of freshly made dressing. The fat globule size distribution was not different from that of control until one month of storage, but after 75 days of storage, the fat globule size distribution pattern changed into the increase of larger size($15{\sim}2.0\;{\mu}m$: $11.4\%$ for control, $30.1-32.3\%$ for 75 days of storage). Hunter color of L value decreased, whereas a and b value increased according to the prolonged storage time. TBARS value at 8 wks of storage was increased upto $10\%$ for storage at $5^{\circ}C$ and $15\%$ for storage at $10^{\circ}C$. Antioxidant activity of salad dressing decreased according to the storage temperature and time: $IC_{50}$ values of DPPH radical scavenging activity of 8 wk storage was 157.4 mg/mL at $5^{\circ}C$ and 194.6 mg/mL at $10^{\circ}C$. Total microbial number of salad dressing was increase to 7.9 log(CFU/mL), but E. coli was not detected Based on present condition, low temperature storage was favorable for better quality of spirulina salad dressing.

• Journal of Soil and Groundwater Environment
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• v.14 no.4
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• pp.23-32
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• 2009

The sorption of europium (Eu (III)) onto kaolinite and the influence of humic acids over a range of pH 3 ~ 11 has been studied by batch adsorption experiment (V/m = 250 : 1 mL/g, $C_{Eu(III)}\;=\;1\;{\times}\;10^{-5}\;mol/L$, $C_{HA}\;=\;5{\sim}50\;mg/L$, $P_{CO2}=10^{-3.5}\;atm$). The concentrations of HA and Eu(III) in aqueous phase were measured by UV absorbance at 254nm (e.g., $UV_{254}$) and ICP-MS after microwave digestion for HA removals, respectively. Results showed that the HA sorption onto kaolinite was decreased with increasing pH and their sorption isotherms fit well with the Langmuir adsorption model (except pH 3). Maximum amount ($q_{max}$) for the HA sorption at pH 4 to 11 was ranged from 4.73 to 0.47 mg/g. Europium adsorption onto the kaolinite in the absence of HA was typical, showing an increases with pH and a distinct adsorption edge at pH 3 to 5. However in the presence of HA, Eu adsorption to kaolinite was significantly affected. HA was shown to enhance Eu adsorption in the acidic pH range (pH 3 ~ 4) due to the formation of additional binding sites for Eu coming from HA adsorbed onto kaolinite surface, but reduce Eu adsorption in the intermediate and high pH above 6 due to the formation of aqueous Eu-HA complexes. The results on the ternary interaction of kaolinte-Eu-HA are compared with those on the binary system of kaolinite-HA and kaolinite-Eu and adsorption mechanism with pH was discussed.