• Korean Journal of Food Science and Technology
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• v.14 no.3
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• pp.257-264
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• 1982

In the present stud changes of some chemical and physical properties of a soybean oil, aerated at 120 ml/min through a porous gas distributor and oxidized at $45^{\circ}C{\sim}180^{\circ}C$, was investigated. The results of the study were as follows: The peroxide, thiobarbituric acid, and iodine value of the soybean oil which was aerated at 120 ml/min increased rapidly as oxidation temperature exceeded over $80^{\circ}C$. The acid value of the oil increased very rapidly as the oxidation temperature passed over $160^{\circ}C$. The content of the unsaturated fatty acid of the oil decreased considerably as the oxidation temperature exceeded over $80^{\circ}C$, whereas that of the saturated fatty acid did not change appreciably. This related well to the changes of the iodine value of the oil subjected to the same experimental conditions. The viscosity and refractive index of the oil increased rapidly as the oxidation temperature passed over $180^{\circ}C$. The following linear relationship hold for the viscosity and refractive index of the oil in the present study. $$V=Aexp({\frac{E}{RT}})$$ where V=viscosity(poise), A=constant, E=activation energy for viscous flow, R=gas constant, T=oxidation temperature$(^{\circ}K)$. The following relationship also hold for the viscosity and refractive index$({n^{20}}_D)$ of the oil at the present experimental conditions. $${n^{20}}_D=1.4614+7.333{\times}10^{-5}t+2.9612{\times}10^{-3}\;InV$$ where t=temperature$(^{\circ}C)$ at which the viscosity was measured.

• Tunnel and Underground Space
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• v.25 no.4
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• pp.320-331
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• 2015

This paper presents a case study of an enhanced geothermal system(EGS) demonstration project conducted in $Gro{\ss}$ $Sch{\ddot{o}}nebeck$, Northerm Germany, focusing on hydraulic stimulation. The project was conducted with doublet system in sandstone and volcanic formations at 4 - 4.4 km depth. Under normal faulting to strike-slip faulting stress regime, hydraulic stimulations were conducted at injection and production wells by massive waterfrac and gel-proppant fracturing. Injectivity index increased from $0.97m^3/(hr^*MPa)$ to $7.5m^3/(hr^*MPa)$ and productivity index increased from $2.4m^3/(hr^*MPa)$ to $10.1m^3/(hr^*MPa)$ by a series of hydraulic stimulations at both wells. After circulation tests through injection and production wells, however, productivity index decreased from $8.9m^3/(hr^*MPa)$ to $0.6m^3/(hr^*MPa)$ in two years. Slip tendency analysis for the stimulation in volcanic layer estimated the required pressure for shear slip and its preferred orientations and it showed reasonable match with actual stimulation results. Through the microseismicity observation for the stimulation of volcanic formation, only 80 seismic events with its moment magnitudes in -1.8<$M_W$<-1.0 were observed, which are unexpectedly low for EGS hydraulic stimulation.

• Journal of Nutrition and Health
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• v.31 no.4
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• pp.729-738
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• 1998

Antioxidants such as vitamin C and E may play a preventive role in the development of cancer and coronary heart disease. The status of vitamins C and E may be affected by lifestyle habits such as smoking , drinking, and exercise. These habits can modify the dietary requirements of vitamin C and vitamin E. the purpose of this study was to determine whether Korean young healthy men and women consume vitamins C and E in sufficient quantities relative to their lifestyle habits. Among the participants in this study, 52% of the men and none of the women were smokers. ; 84% of all subjects drank alcohol more than once a week ; and the men exercised more often than the women. The concentrations of serum total , HDL-, and LDL- cholesterol were higher in the women than in the men, but the serum triglyceride concentrations were higher in the men than in the women. The men consumed less satuated fat than the women (p<0.05) . The daily intakes of vitamin C for the men and the women were 47.1mg and 65.6mg, respectively. On the other hand , the daily vitamin E intake was higher in the men (11.8mg) than women(6.9mg). The serum $\alpha$-tocopherol concentrations of all subjects were in a normal range, and in no subjects were they below the minimum value of ranges. However, about 19% of male subjects and 10% of female subjects showed deficient status, although the mean serum vitamin C levels were normal . Lifestyle habits fo the sort mentioned above have little influence on the serum vitamin C and $\alpha$-tocopherol concentrations. The serum $\alpha$-tocopherol concentration had a positive correlation with total fat and alcohol consumption. The serum vitamin C concentration was positively associated with regular exercise, but it was negatively correlated with the number of cigarettes smoked. Meanwhile, the serum lipid persoxide concentration , the indirect index of oxidative stress, was influenced by certain variable such as body mass index , the number of cigarettes smoked , alcohol consumption, energy expenditure, vitamin C intake, and serum ${\gamma}$-tocopherol concentration. Serum lipid peroxide concentration was positively associated with body mass index, the number of cigarette smoked , serum triglyceride , and HDL-cholesterol concentration. In conclusion , the vitamin E requirements of the subjects were met by the Recommended Daily Allowance (RDA) regardless of lifestyle habits. However, serum vitamin C concentrations showed individual variation and was below the normal ranges. Smoking and exercise influenced serum vitamin C concentration. Therefore, a reevaluation of the requirements of vitamin C relative to lifestyle habits is necessary.

• Journal of Nutrition and Health
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• v.31 no.9
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• pp.1481-1497
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• 1998

The purpose of this study was to determine the relation between serum lipid profiles, apolipoprotein E phenotype, and dietary patterns in a cross-section of healthy individuals from Cheju-Do. Age, gender, anthropometric measurements, blood pressure, dietary consumption, drinking / smoking habits and menopausal status were surveyed. Total cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride, fasting blood glucose, and insulin levels were measured from overnight fasting blood. The study involved a total of 286 individuals(147 men and 139 women) between the ages of 20 and 60 years old. All of the subjects were recruited from a population of healthy individuals living in Cheju-Do. The results of the study are as follows : 1) Among the males, those in their 20's had the maximum food intake, while those in their 40's had the minimum food intake. For the females, food intake was the highest for those in their 30's. Energy and nutrient intakes were directly proportional to the amount of food intake. Men in their 30's were heavier than other men and women in their 40's were heavier than other women. The activity index for men in their 20's and 30's appeared to be lower than that of men above 40. The activity index of women in their 20's appeared to be lowest among all aged groups, and the index appeared to increase from the age of 30 onwards. 2) In terms of changes In serum constituents with age, men in their 40's appeared to have the highest levels of serum constituents such as lipids, glucose, and insulin. Men in their 50's showed the highest levels of serum LDL-cholesterol and glucose. Men in their 30's showed peak levels of serum triglycerides. On the other hand, women in their 50's appeared to have peak levels of serum total cholesterol, LDL-cholesterol, and triglycerides. There was no ch:ange with age in HDL-cholesterol and insulin levels for men and women. The percentage of the subjects had the following apo E phenotypes : E3/3, 91.3% ; E3/2, 5.4% ; E4/3, 2.5% ; E4/2, 0.7%. Lee's reserch with Korean female college students showed that the percentage of ApoE3/3, E3/2, E 4/2, E4/3, and E4/4 were 84.8%, 6.7%, 6.7%, 0.9%, 0.9%, respectively. The number of samples with ApoE mutation was so small that there was no statistical significance in the relation between apolipoprotein E phenotype and se겨m lipids. 3) To investigate the relati onship between weight and serum constituents, the subjects of this study were divided into three groups by BMI underweight, normal weight, and overweight. The serum constituents of men and women below the age 40 in the overweight groups belonged to the normal domain. On the other hand, serum cholesterol levels of both men and women above the age 40 in the overweight groups remained in the borderline-high region(above 200mg/dl), and the mean value of LDL-cholesterol(above 130mg/dl) and triglycerides of men were above normal. Fasting blood glucose levels also remained in the borderline-high region. Total cholesterol levels of women above the age 40 in the overweight group was in the borderline-high region. (Korean J Nutrition 31(9) : 1481-1497, 1998)

• Journal of Korean Society on Water Environment
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• v.36 no.2
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• pp.125-136
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• 2020

In this study, we identified the major pollution-zones of the mainstream and its tributaries of Gongneung stream and investigated their pollution sources based on water quality, flowrate and pollution-load data of the stream having the characteristics of the urban-rural complex to examine the effect of the tributaries on the water quality changes in the mainstream. The water quality and flowrate data were collected for 10 months (2018 ~ 2019) at 3 points of mainstream and ten tributaries. Water quality index (WQI), load duration curve (LDC), discharge load density (DLD)and delivery ratios for each tributary were obtained so as to investigate the pollution characteristics and some of the information visualized on GIS. The main pollution-zone in the Gongneung stream was in the middle and lower streams, and the tributaries that may affect the pollution of the area were JS, JY, SL and SM. JS and SL had low WQI levels (34.7/37.5) and DLD (kg/d/㎢) of BOD and T-P were relatively high in JY (99.2/6.00) and SL (60.0/2.07). BOD and T-P delivery ratios in JS were high (0.94/0.83), suggesting that JS had significant influence on the water quality of the main pollution-zone in the Gongneung stream. Meanwhile, SM having a high T-P delivery ratio (0.97) was found to be more affected by the non-point source due to the higher LDC excess rate (%) in the low flow compared to high flow. This study provides basic data on the water quality and pollution characteristics of the Gongneung stream, and the analysis results are expected to be used as examples for identifying the main pollution-zone and tributaries of stream and their pollution sources.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1603-1610
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• 2012

The effects of moisture content on the physical properties of cereal extrudates were investigated. Cereal flours (rice, wheat, corn, barley, and oat) were extruded at a barrel temperature of $130^{\circ}C$, feed rate of 120 g/min, and various moisture contents (20, 22.5, 25, 27.5, and 30%). Proximate content, expansion index, specific length, bulk density, breaking strength, apparent elastic modulus, water absorption index (WAI), water solubility index (WSI), specific mechanical energy (SME) input, paste viscosity, and color values were analyzed. Expansion ratio of extruded corn flour was higher than that of other extrudates at low moisture content. Bulk density, specific length, and elastic modulus in all cereals decreased with an increase in moisture content. The WAI increased with an increase in moisture content, whereas WSI decreased. SME input of extruded corn flour was higher than those of other cereal flours at lower moisture content, whereas that of oat flour extrudate was lower than those of other cereals at higher moisture content. Lightness of extruded rice flour was lighter than those of other cereals while that of extruded barley flour was darker.

• Journal of the Korean Geotechnical Society
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• v.33 no.4
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• pp.35-46
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• 2017

Most of high carbon fly ashes (HCFA) are discarded in landfills with high costs due to low recycling rate. This study aims to explore the geotechnical behaviors of HCFA mixtures reinforced with fiber and sand. A series of compaction test, unconfined compressive strength test and modified 1D consolidation test with bender element were performed. Specimens were prepared at their optimal moisture contents based on the results of compaction tests. The results of this study demonstrate that the inclusion of fibers to the matrix of HCFA increases unconfined compressive strength (UCS), strain at UCS, and maximum shear modulus ($G_{max}$) at a given void ratio. Reinforcement with sand increases UCS of HCFA; while the strain at UCS is irrelevant with sand fractions. Sand particles may disrupt the direct contacts between HCFA particles at low sand content, resulting in a decrease in $G_{max}$. However, it can be expected that the mixtures with sand content larger than 20% are in dense state; thus, $G_{max}$ of HCFA reinforced with sand shows greater value than that of unreinforced HCFA compacted with the same energy. Regardless of types of reinforcement, the compression index ($C_c$) of both fiber and sand reinforced HCFA is mainly determined by initial void ratio.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.4
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• pp.567-576
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• 2017

In a performance-based design, the structural safety is estimated from pre- defined damage states and corresponding damage indices. Both damage states and damage indices are well defined for above-ground structures, but very limited studies have been performed on underground structures. In this study, we define the damage states and damage indices of a cut-and-cover box tunnel which is one of typical structures used in metro systems, under a seismic excitation from a series of inelastic frame analyses. Three damage states are defined in terms of the number of plastic hinges that develop within the structure. The damage index is defined as the ratio of the elastic moment to the yield moment. Through use of the proposed index, the inelastic behavior and failure mechanism of box tunnels can be simulated and predicted through elastic analysis. In addition, the damage indices are linked to free-field shear strains. Because the free-field shear strain can be easily calculated from a 1D site response analysis, the proposed method can be readily used in practice. Further studies are needed to determine the range of shear strains and associated uncertainties for various types of tunnels and site profiles. However, the inter-linked platform of damage state - damage index - shear wave velocity - shear strain provides a novel approach for estimating the inelastic response of tunnels, and can be widely used in practice for seismic designs.

• Journal of Nutrition and Health
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• v.47 no.6
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• pp.403-415
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• 2014

Purpose: This study was conducted in order to investigate the nutrient and food intake status, and dietary quality in Korean adults according to abdominal obesity based on waist circumference. Methods: We analyzed data from the combined 2010~2012 KNHANES (Korean National Health and Nutrition Examination Survey). The analysis included 6,974 adults aged 40 to 64 years. In this study, according to abdominal obesity based on waist circumference (male ${\geq}$ 90 cm, female ${\geq}$ 85 cm), we classified the subjects into the obesity group (male, n = 775, female, n = 1,113) and control group (male, n = 2,038, female, n = 3,048). The nutrient and food group intake, ND (nutrient density), NAR (nutrient adequacy ratio), MAR (mean adequacy ratio), INQ (index of nutritional quality), DDS (dietary diversity score), and DVS (dietary variety score) were analyzed using data from the 24-recall method. Results: For male, no significant difference in quality index of the diet was observed between the obesity group and the normal group. In female, in diet quality (ND, NAR, and INQ), vitamin $B_2$ (ND, NAR, and INQ) calcium (NAR), phosphorous (ND, INQ) and potassium (ND) of the obesity group was significantly lower than those of the control group. DDS and DVS in the obesity group (3.57, 30.95) were significantly lower than those of the control group (3.68, 32.84) (p = 0.0043, 0.0002). DVS (DVS ${\geq}$ 39.9) showed association with lower risk of waist obesity in a logistic regression model after adjustments for multiple confounding factors including age, education, income, alcohol intake frequency, smoking, physical activity, energy intake, and body mass index (OR: 0.616, 95% CI: 0.420-0.903). Conclusion: In conclusion, females with abdominal obesity had lower micronutrient intake quality, DVS than those of the control group. In Korean females, food intake variety can adversely affect waist circumference.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.46-56
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• 2017

The Youngsan River estuary was physically changed by the construction of a sea embankment at near the mouth of estuary. Weirs were also constructed recently in the freshwater zone and it was reported that algal blooms occur more frequently. The freshwater introduced into saltwater zone from sluice gates of the embankment affects water quality but it has not been addressed that how the freshwater inputs influence the health of marine ecosystem. In this study, we used the data of water properties and phytoplankton communities collected at three stations for 4 days including before the freshwater discharge, during the discharge and after 1 and 2 days of discharge events. WQI(water quality index), TRIX (trophic status index) and P-IBI(phytoplankton index of biotic integrity) were used to evaluate the ecosystem health and long-term data were also utilized to determine the criteria for P-IBI. The results showed that grades of the ecosystem health assessed by the indices were low at the station near the gates and increased as downstream. However, the temporal pattern of grades was different depending on methods. Grades of WQI and TRIX decreased during the discharge and restored after the discharge whereas the grades of P-IBI decreased slightly even after the discharge. This suggests that P-IBI is more applicable to estuarine systems where experience extreme change of water properties than WQI and TRIX since P-IBI includes phytoplankton that can respond quickly to the change.