• Tribology and Lubricants
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• v.32 no.2
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• pp.50-55
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• 2016

Recently, a double-side machining process has been adopted in fabricating a sapphire glass to enhance the manufacturability. Double-side lap grinding (DLG) is one of the emerging processes that can reduce process steps in the fabrication of sapphire glasses. The DLG process uses two-body abrasion with fixed abrasives including pallet. This process is designed to have a low pressure and high rotational speed in order to obtain the required material removal rate. Thus, the temperature is distributed on the DLG platen during the process. This distribution affects the shape of the substrate after the DLG process. The coolant that is supplied into the cooling channel carved in the base platen can help to control the temperature distribution of the DLG platen. This paper presents the results of computational fluid dynamics with regard to the heat transfer in a DLG platen, which can be used for fabricating a sapphire glass. The simulation conditions were 200 rpm of rotational speed, 50℃ of frictional temperature on the pallet, and 20℃ of coolant temperature. The five cases of the coolant flow rate (20~36 l/min) were simulated with a tetrahedral mesh and prism mesh. The simulation results show that the capacity of the generated cooling system can be used for newly developed DLG machines. Moreover, the simulation results may provide a process parameter influencing the uniformity of the sapphire glass in the DLG process.

• Korean Journal of Organic Agriculture
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• v.27 no.3
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• pp.271-288
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• 2019

It has continuously promoted to scale up the agricultural management body in order to cope with the market-opening pressure such as the UR negotiation, the DDA negotiation, and more conclusions of FTAs and to enhance the competitiveness of our agriculture. This study evaluated the factors associated with production organization participation centered on environmentally-friendly agriculture farmers in order to improve the production efficiency of environmentally-friendly agriculture in the aspect of production. In order to achieve this objective, this study evaluated the factors that contributed to participating in an organization using the bivariate probit model focusing on environmentally-friendly agriculture farmers in Chungnam. This study examined the validity and reliability of the study model through exploratory factor analysis. The results of factor analyses identified four factors: "distribution", "production", "organization operation", and "social capital". The results of the bivariate probit model showed that distribution significantly affected production activities and distribution, organization operation, agricultural income, and gender significantly influenced sale activities. Environmentally-friendly production organization had not been able to provide the productive support that was needed for local farmers to produce environmentally-friendly agricultural products in a region. Additionally, farming education did not provide the information needed by the farmers. Although producers had a network within a production organization, it was operated mainly for administrators. Therefore, participants felt somewhat lacking. This study identified the level of organization of producer organizations in Chungnam area, where environmentally-friendly agriculture is well activated. This study suggested implications for future production organization participation by evaluating factors affecting participation quantitatively.

• Wind and Structures
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• v.25 no.2
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• pp.101-129
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• 2017

Local transient extreme wind loads caused by group tower-related interference are among the major reasons that lead to wind-induced damage of super-large cooling towers. Four-tower arrangements are the most commonly seen patterns for super-large cooling towers. We considered five typical four-tower arrangements in engineering practice, namely, single row, rectangular, rhombic, L-shaped, and oblique L-shaped. Wind tunnel tests for rigid body were performed to determine the influence of different arrangements on static and dynamic wind loads and extreme interference effect. The most unfavorable working conditions (i.e., the largest overall wind loads) were determined based on the overall aerodynamic coefficient under different four-tower arrangements. Then we calculated the one-, two- and three-dimensional aerodynamic loads under different four-tower arrangements. Statistical analyses were performed on the wind pressure signals in the amplitude and time domains under the most unfavorable working conditions. On this basis, the non-Gaussian distribution characteristics of aerodynamic loads on the surface of the cooling towers under different four-tower arrangements were analyzed. We applied the Sadek-Simiu procedure to the calculation of two- and three-dimensional aerodynamic loads in the cooling towers under the four-tower arrangements, and the extreme wind load distribution patterns under the most unfavorable working conditions in each arrangement were compared. Finally, we proposed a uniform equation for fitting the extreme wind loads under the four-tower arrangements; the accuracy and reliability of the equation were verified. Our research findings will contribute to the optimization of the four-tower arrangements and the determination of extreme wind loads of super-large cooling towers.

• Transactions of Materials Processing
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• v.32 no.6
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• pp.311-320
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• 2023

Recently, lightweight of automotive parts has been required to solve environmental problems caused by global warming. Accordingly, research and development are proceeded on manufacturing of parts using aluminum that can replace steel for lightweight of the automotive parts. In addition, high strength aluminum can be applied to body parts in order to meet both requirements of lightening and improving crash safety of vehicle. In this study, hot blow forming of roof side rail is employed to manufacturing of the automotive parts with high strength aluminum tube. In hot blow forming, longer forming times and excessive thinning can be occurred as compared with conventional manufacturing processes. So optimization of process conditions is required to prevent excessive thinning and to uniformize thickness distribution with fast forming time. Mechanical properties of high strength aluminum are obtained from tensile test at high temperature. These properties are used for finite element(FE) analysis to investigate the effect of strain rate on thinning and thickness distribution. Variation of thickness was firstly investigated from the result of FE analysis according to tube diameter, where the shapes at cross section of roof side rail are compared with allowable dimensional tolerance. Effective tube diameter is determined when fracture and wrinkle are not occurred during hot blow forming. Also FE analysis with various pressure-time profiles is performed to investigate the their effects on thinning and thickness distribution which is quantitatively verified with thinning factor. As a results, optimal process conditions can be determined for the manufacturing of roof side rail using high strength aluminum.

• Journal of the Korea Convergence Society
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• v.6 no.3
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• pp.19-28
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• 2015

To figure out the causes of obesity against middle-aged women, this study aimed to provide basic data for setting an obesity-related policy through analysis on diverse related factors. Against the healthy middle-aged women who visited 'N' Hospital Health Center in Incheon from April to November 2014, anthropometric assessment, body composition test and abdominal fat distribution test were conducted using Fat-CT. They were carried out against 159 women who agreed with the purpose of the study, using BMD, Q-CT. According to Fat-CT, subcutaneous and visceral types accounted for 39% (76 women) and 61% (119 respondents) respectively. In terms of BMI, 'underweight ($18.5kg/m^2$)' and 'overweight ($25kg/m^2$ or above)' were 13 women (6.7%) and 60 women (30.8%) each with the average of $23.5{\pm}4.11kg/m^2$. Mean while, waist circumference, diastolic blood pressure, systolic blood pressure and neutral fat were statistically significant at the 5% significance level. As getting older, muscle weakness offsets increase in body weight with abdominal obesity. A group with low BMI should also be considered due to increase in waist circumference.

• Clinical and Experimental Pediatrics
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• v.48 no.7
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• pp.745-752
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• 2005

Purpose : Adolescent obesity is known to be associated with complications such as hypertension, coronary artery disease and insulin resistance. We measured the common carotid artery by ultrasound as a predictor of atherosclerosis, and investigated the relationship between carotid artery parameters and serum cytokines in obese adolescents. Methods : Twenty-nine obese adolescents(16-17 years old, obesity index>130 percent) and twentyseven normal controls were included. Obesity index and body mass index were calculated from their height and weight. Skin fold thickness was measured at the triceps, and fat mass and fat distribution by bioelectrical impedence analysis. Blood pressure was measured at resting state and serum lipid, insulin, and homocysteine levels after a 12-hour fasting period. Intimal wall thickness, systolic and diastolic diameters of the common carotid artery were measured by ultrasound, and compliance and distensibility calculated by equation. Results : Systolic and diastolic diameters of the carotid artery significantly correlated with arm circumference, body mass index, fat distribution and fat mass. The higher systolic blood pressure was, the larger systolic and diastolic diameter. The higher diastolic blood pressure was, the larger carotid intimal thickness. Insulin levels had positive correlations with systolic, diastolic diameters and serum homocysteine level with intimal thickness. Conclusion : The carotid artery diameter significantly increased with the degree of obesity and blood pressure. The carotid intimal wall thickness significantly correlated with diastolic blood pressure. Measurement of carotid artery thickness, insulin and homocysteine levels might be useful to predict the development of coronary artery disease.

• Korean Journal of Community Nutrition
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• v.7 no.1
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• pp.76-85
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• 2002

Since the 1970s, the average life expectancy of Koreans has been increasing. Our concerns are not simply about longevity, but also about disability-free life. lately, Sasang constitutional medicine has attracted public attention, especially with respect to the elderly. The purpose of this study was to investigate the food habits, nutrients intake, and disease distribution among the elderly, according to their Sasang constitutions. The results are as follow : The distribution of constitutions of the subjects were Tae-eum 48.8%, So-yang 27.4%, So-eum 22.6%, and So-yang + So-eum 1.2%. In both elderly men and women, body weight, percent ideal body weight, and diastolic pressure of the Tae-eum were significantly higher than those of other constitutions. In both men and women, the level of hemoglobin in the Tae-eum was significantly higher than those of other constitutions. The level of LDL-cholesterol was higher, and the level of HDL-cholesterol was lower in the So-eum elderly women. Food habits of the So-eum were the most irregular, and nutrients intake of the So-eum was lower than that of other constitutions in both elderly men and women. In elderly men, the incidence of hypertension was the highest in the Tae-eum, and the incidence of gastritis was the highest in both So-yang and So-eum. In elderly women, the incidence of fatty liver was the highest in the Tae-eum and So-yang, and gastritis and hypertension were the highest in the So-eum. In the elderly, obese and anemic persons were significantly more in the Tae-eum and the So-eum, respectively. The results of this study showed that there were significant differences of physical, characeristics, food, habits, and distributions of disease for the subjects according to each Sasang constitutions. Intake of nutrient was poor, regardless of Sasang constitutions, in both men and women.

• The Korean Journal of Pharmacology
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• v.31 no.2
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• pp.251-259
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• 1995

Pharmacokinetics and pharmacodynamics of metoprolol, a selective beta-l blocker, were examined for 360 minutes after intravenous bolus administration of metoprolol to 6 dogs. Plasma concentration and excreted amount in the urine metoprolol were measured by liquid chromatography with fluorescence detection. PR interval and heart rate were measured by ECG monitoring. Blood pressure was monitored through intraarterial catheter in femoral artery and cardiac output by thermodilution method using Swan-Ganz catheter. To analyze the effect site concentration-response relationship, plasma concentration and pharmacological effects were simultaneously fitted to a two pharmacokinetic compartment linked to pharmacodynamic model with NONLIN program. Results are as follows. 1) The plasma concentration of metoprolol after intrvenous injection decreased biexponentially. The terminal half-life estimated was $1.33{\pm}0.40$ hours and the volume of distribution at steady state (Vdss) and the total body clearance were $1.04{\pm}0.4\;L/kg,\;6.55{\pm}2.21\;L/hr$, respectively. The central compartment volume of distribution and peripheral compartment volume of distribution were $0.35{\pm}0.14L/kg\;and\;0.69{\pm}0.34L/kg$. The renal clearance and intercompartment clearance were $0.53{\pm}0.25\;L/min\;and\;0.35{\pm}0.19\;L/min$. 2) Simulated biophase concentration-response curve shows hyperbolic relationship and the estimated concentration-effect relationship was best explained by Emax model when the prolongation of PR interval and the reduction of the heart rate were used as pharmacodynamic parameters. Emax and EC50 were estimated to be $26.3{\pm}4.7\;msec\;and\;88.8{\pm}82.3\;g/ml$ for PR interval, and $48.7{\pm}18.8\;beats/min\;and\;113.5{\pm}78.7\;ng/ml$ for heart rate, respectively. 3) The changes of cardiac output-effect site concentration relationship was best fitted by a linear model and the slope of the relationship was $0.005{\pm}0.003$. Diastolic blood pressure-effect site concentration relationship was also explained by the linear model and the slope of the relationship was $0.038{\pm}0.034$.

• Journal of the Korean Home Economics Association
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• v.24 no.4
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• pp.57-68
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• 1986

The present survey was designed to investigate correlations among blood pressure, nutritional intakes, and various environmental factors in Korean adult males, and to observe the difference in dietary intakes between hypertensive patients and normotensive subjects. Two hundred forty-three adult men from Seoul and rural areas were interviewed about their food intakes, dietary patterns, food habits, and general environmental factors from December 20, 1982 to February 15, 1983. Their dietary intakes were surveyed by means of 24-hour recall diet method. Dietary score card was used in order to evaluate the quality of routine diet of the subject. Variables of environmental factors and factors related to hypertension were expressed as percentage, and the differences in nutrient intake and food score of each sub-group were examined by means of t-test. Correlation of all the variables were analyzed by Pearsons Correlation Coefficient. The results obtained are summarized as follows: 1. 38% of the subjects were between the ages of 40~49, and about one-half of the subjects were middle or high school graduates. 28% of the subjects earned 210, 000~350, 000 Won per month, and income distribution was almost identical to that of the urban population of Korea. 2. There was more overweight or obese found in the hypertensive patients than in the normotensive subjects. About 40% of the hypertensive patients reported a family history of hypertension, and their knowledge about hypertension was rather poor, but slightly better than the normotensive subjects. The patient group had less adherence to smoking and alcohol compared with the normotensive subjects, but no difference was observed in coffee drinking. The mean value of the blood pressure for the normotensive subjects was 127/86mmHg and 175/109mmHg for the hypertensive group. 3. Nutrient intake for the hypertensive group was lower for most of nutrients than in the healthy group. Hypertensive patients on diet therapy consumed less calories and carbohydrates compared with those who do not follow diet therapy. 4. There was no difference intake of these food groups between patients and the healthy group. Food score was strongly related to consumption of animal protein, saturated fats, Calcium, Iron, Vitamin A, Riboflavin, and Vitamin C, which are prone to be deficient in the typical Korean diet. 5. Blood pressure had a strong positive correlation with age, body weight, and socioeconomic level. In addition, monthly income was positively related with age and education level. 6. Three was a positive relationship between blood pressure and consumption of vegetable protein, and a negative relationship with consumption of Calories, Carbohydrates, Calcium, Iron, Vitamin A, Vitamin B1, Niacin, and Vitamin C. Animal protein intake increased as income and education levels increased, but this tendency was opposite for carbohydrates. In summary, nutritional intakes are strongly correlated with various environmental factors and the level of blood pressure. There was no difference between normotensive and hypertensive subjects with respect to the quality of food consumed except restricting energy and carbohydrate in the patient group.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.1
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• pp.11-18
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• 2010

Purpose: In every time radiation therapy set up errors occur because internal anatomical organs move due to breathing and change of patient's position. These errors may affect the change of dose distribution between target area and normal structure. This study investigates the usefulness of body-fix in clinical treatment. Materials and Methods: Among 55~60 aged male patients who has hepatocellular carcinoma in area of liver's couinaud classification, we chose 10 patients and divided two groups by using body-fix or not. When applying body-fix, we maintained a vacuum of 80 mbar pressure by using vacuum pump (Medical intelligence, Germany). Patients had free breathing with supine position. After working to fuse and consist MV-CT (megavoltage computed tomography) with KV-CT (kilovoltage computed tomography) obtained by 5 times treatments, we compared and analyzed set up errors occurred to (Right to Left, RL) of X axis, (Anterioposterio, AP) of Z axis, (Cranicoudal, CC) of Y axis. Results: Average Set up errors through image fusion showed that group A moved $0.3{\pm}1.1\;mm$ (Cranicoudal, CC), $-1.1{\pm}0.7\;mm$ (Right to Left, RL), $-0.2{\pm}0.7\;mm$ (Anterioposterio, AP) and group B moved $0.62{\pm}1.94\;mm$ (Cranicoudal, CC), $-3.62{\pm}1.5\;mm$ (Right to Left, RL), $-0.22{\pm}1.2\;mm$ (Anterioposterio, AP). Deviations of X, Y and Z axis directions by applying body-fix indicated that maximum X axis was 5.5 mm, Y axis was 19.8 mm and Z axis was 3.2 mm. In relation to analysis of error directions, consistency doesn't exist for every patient but by using body-fix showed that the result of stable aspect in spite of changes of everyday's patient position and breathing. Conclusion: Using body-fix for liver cancer patient is considered effectively for tomotherapy. Because deviations between group A and B exist but they were stable and regular.