• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.285-293
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• 2016

The high velocity oxygen fuel(HVOF) thermal spray is a kind of surface modification techniques to produce the sprayed coating layer. This process is to form the coating layer after spraying the powder to molten or semi-molten state by the ultra-high speed at the high-temperature heat source and conflicting with a substrate. The efficiency of thermal spraying is dropped, however, because the semi-molten powder in a spray process become a factor that degrades the mechanical property by the formed pore within the coating layer. Therefore, it is necessary to melt completely the thermal spray powder in order to produce the coating layer with an optimal adhesive force. In this study, to improve the wear resistance, corrosion resistance and heat resistance, the plungers of high-speed and ultra-high pressure reciprocating hydraulic pumps used in ironworks are manufactured with STS $420J_2$ and are coated by the powders of WC-Co-Cr and WC-Cr-Ni including the WC of high hardness using a HVOF thermal sprayer developed in this laboratory. These are called by the surface-modified plungers. The surface roughness, hardness, and surface and cross-sectional microstructure of these two surface-modified and conventional ceramic plungers are measured and compared before operation with after operation for 100 days. It is found that the values of centerline average surface roughness and maximum height for conventional ceramic plunger are 9.5 to 10.8 and 5.2 to 5.7 times higher than those of surface-modified ones coated by WC-Co-Cr and WC-Cr-Ni because the fine tops and bottoms on surface roughness curve of conventional ceramic plunger are approximately 100 times higher than those of surface-modified ones. In addition, the pores and scratches in the surface microstructure are considerably formed in the order of conventional ceramic, WC-Cr-Ni and WC-Co-Cr surface-modified plungers. The greater the WC content of high hardness powder is less the change in the plunger surface.

• Journal of Nutrition and Health
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• v.30 no.10
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• pp.1180-1187
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• 1997

Cigarette smoking is a major risk factor of atherosclerosis and has been reported to contain an abundance of free radical species which could be expected to deplete antioxidants such as vitamin C . The present study was designed to investigate the relationship between smoking, plasma lipid and lipoprotein concentration, and plasma vitamin C level. Fifty-five healthy male smokers and 32 non-smokers were investigated in the study. Mean age, body weight , BMI and blood pressure made no differences in both smokers and non-smokers. Significantly, smokers has higher plasma total cholesterol and LDL-C , and lower HDL-C /LDL-C ratio compared with non-smokers. Plasma level of thiobartiturin acid reactive substances(TBARS), indicator of lipid peroxidation and increased susceptibility of LDL towards lipid perosidation, were elevated in smokers(p<0.001), while the plasma vitamin C level of smokers was significantly lower than that of non-smokers(p<0.05), indicating that elevated lipid peroxidation are associated with decreased plasma vitamin C content. In non-smokers a significantly positive correlation was observed between dietary vitamin C intake and plasma levels, but no such association observed in smokers. Lack of such a relationship and the decreased plasma vitamin C level in the smokers suggest that smoking may cause increased turnover of the plasma antioxidant. Consuquently, the sustained free radical load derived from smoking causes an imbalance in oxidant/antioxidant status and it could be expected that cigarette smoking renders plasma LDL more susceptible to oxidative modification . In the present study the possible explanations for that cigarette smokers have a higher risk of cardiovascular disease include the changes of blood lipid and lipoprotein concentration, and plasma vitamin C status which might have protective functions against free radicals -medaited lipid peroxidation.

• Korean Journal of Community Nutrition
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• v.16 no.4
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• pp.439-453
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• 2011

This study was performed to determine dietary and lifestyle factors associated with hypertension in Korean adolescents. Study subjects were 12~19 years (n = 521) adolescents who participated in the 2005 Korean National Health and Nutrition Examination Survey (KNHANES III). Subjects were divided into the hypertensive group (HG, n = 102) and normotensive group (NG, n = 419) by '2007 Korean children and adolescents growth standard' and the relationships between blood pressure and physical measurement, nutrients intakes, eating behaviors and health related factors were analyzed. HG showed significantly higher levels in weight, waist circumference and BMI than NG. The amount of nutrient intakes was not different between NG and HG. Index of nutritional quality (INQ) for phosphate was higher in HG compared with NG. In both male and female HG, INQ for iron was higher but INQ for vitamin B1 was lower than NG. HG revealed higher consumption frequencies of snack, yoghurt, and ice cream compared with NG. In eating and behavioral factors, 'dinner with family', 'eat proper amount', 'keep Korean traditional diet', alcohol drinking, and mean alcohol intake were significantly different between the two groups. By logistic regression method, risk factors for hypertension revealed in this study were gender (male), age (15~19 years), BMI (${\geq}\;85$ percentile), and not keeping Korean traditional diet. These results suggest that education program for hypertension prevention in adolescents should include eating habits improvement and lifestyle modification as well as weight control.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.147-156
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• 2016

The purpose of this study was to identify the factors associated with the improvement of metabolic syndrome, and provide basic data for the health management of clients. The subjects were 280 adults who were diagnosed with metabolic syndrome in 2013, and who were examined from January 2013 to December 2014. The data were analyzed by descriptive statistics, t-test, ${\chi}^2$-test, and logistic regression analysis with SPSS WIN 18. The change rate from 3 to 2 risk factors was 60.6% among those clients whose metabolic syndrome improved. The improvement group showed a decrease in their waist circumference, systolic blood pressure, triglycerides and increase in their HDL cholesterol in 2014 compared to 2013, as well as decreased drinking, increased exercise, proper calorie, protein and carbohydrate uptake, and increased consumption of a lipid lowering agent. Exercise, calorie uptake and maintenance of an oral hypoglycemic drug influenced the improvement of the metabolic syndrome. In conclusion, it is necessary to have an intervention program including exercise enhancement and diet modification and to reinforce the health education for continuing health management.

• Journal of Korean Academy of Rural Health Nursing
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• v.7 no.1
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• pp.5-17
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• 2012

Purpose: The objectives of this study were to investigate the prevalence of the metabolic syndrome (MetS) and to identify associated factors with MetS among rural residents. Methods: Data were collected from 1,196 subjects over aged 30 years by a self-administered questionnaire, physical measurement, and blood test in a rural area. The prevalence of MetS was determined by the criteria of the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) and 2005 the Korean society for the study of obesity. Results: The prevalence of MetS was 40.5% for men, 49.2% for women. The prevalence of risk factors of MetS was 57.4% for elevated blood pressure, 49.0% for low HDL-cholesterol, and 48.6% for abdominal obesity. Unemployment and higher Body mass index (BMI) were associated factors for MetS regardless of gender. And higher age and physical inactivity in women only increased the odds of the MetS. Especially, BMI was a strong risk factor of MetS in both men and women. Conclusion: The prevalence of metabolic syndrome was higher in a rural area. Therefore, health care providers should develop lifestyle modification program to increase physical activity level and to prevent the obesity among rural residents in order to decrease the prevalence of MetS.

• Fire Science and Engineering
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• v.31 no.4
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• pp.95-102
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• 2017

The fires in the traditional markets often occur recently with the most of them expanded into great fires so that the damage is very serious. The status of traditional markets handling the distribution for ordinary people is greatly shrunk with the aggressive marketing of the local large companies and the foreign large distribution companies after the overall opening of the local distribution market. Most of the traditional markets have the history and tradition from decades to centuries and have grown steadily with the joys and sorrows of ordinary people and the development of the local economy. The fire developing to the large fire has the characteristics of the problem that the fire possibility is high since all products can be flammable due to the deterioration of facilities, the arbitrary modification of equipment, and the crowding of the goods for sale. Furthermore, most of the stores are petty with their small sizes so that the passage is narrow affecting the passage of pedestrians. Accordingly, the traditional markets are vulnerable to fire due to the initial unplanned structural problem so that the large scale fire damage occurs. The study is concerned with systematically classifying and analyzing the result by applying the TRIZ tool to the fire risk factors to extract the fundamental problem with the fire of the traditional market and make the active response. The study was done for preventing the fire on the basis of it and the expansion to the large fire in case of fire to prepare the specific measure to minimize the fire damage. On the basis of the fire expansion risk factor of the derived traditional market, the study presented the passive measures such as the improvement of the fire resisting capacity, the fire safety island, etc. and the active and institutional measures such as the obligation of the fire breaking news facilities, the application of the extra-high pressure pump system, the divided use of the electric line, etc.