• 한국신재생에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.554-554
• /
• 2009

지구온난화는 범지구적 환경문제로 매우 빠른 속도로 진행되면서 그 심각성을 더해가고 있다. 특히 해수면 상승이나 대형 태풍, 홍수, 가뭄 등의 이상기후가 빈번하게 발생되며 생태계에도 심각한 타격을 주고 있다. 이러한 지구온난화를 유발하는 물질들에 대해 도쿄의정서(Annex A)에 6대 온실가스($CO_2$ (이산화탄소), 메탄($CH_4$), $N_2O$(아산화질소), PFC(불화탄소), HFC(수소화불화탄소), $SF_6$(육불화황))로 정의 하여 규제대상으로 분류하고 있다. $CO_2$를 제외한 Non-$CO_2$ 온실가스들은 배출량이 $CO_2$에 비해 매우 낮지만 GWP(지구온난화지수)가 매우 커 지구온난화에 미치는 영향이 상당하다. 최근 이산화탄소 이외에 지구온난화 문제를 일으키는 온실가스에 대한 많은 관심으로 대상가스의 처리 또는 재활용을 위한 신기술 및 신공정 개발에 박차를 가하고 있다. 온실가스 중 HFCs는 GWP가 1300으로 미량의 배출로도 심각한 기후변화를 일으킬 수 있는 물질로, 우리나라의 경우 1990년 이후 HFCs 배출량 증가율은 연 평균 4.9% ~ 13.8%이다. 국내외 온실가스 처리기술은 대부분 CO2에 대한 연구개발 및 실증화가 지배적이고, non-CO2에 대한 처리기술 개발수준은 미흡할 뿐만 아니라 본 연구 대상인 HFCs 의 경우에는 처리기술 연구개발이 전무하다. 특히 HFCs는 냉매 또는 발포제로 사용되는데 일반적으로 사용 후 특별한 처리과정 없이 대기중으로 배출된다. 본 연구에서는 non-CO2 가스인 HFC-134a 를 대상으로 혼합가스에서 분리 회수를 위해 하이드레이트 기술을 접목시켜 경제적, 친환경적인 기술개발을 목적으로 한다. kinetic 반응장치와 고압반응기 및 magnetic drive system 을 이용하여 stirring speed와 driving force에 따른 HFC-134a 하이드레이트 형성속도의 상관관계를 제시하고자 한다.

• Journal of Society of Preventive Korean Medicine
• /
• v.21 no.2
• /
• pp.35-44
• /
• 2017

Objectives : The purpose of this study was to investigate the association between quality of life and Mibyeong index of abnormal symptoms by the Mibyeong state. Methods : A total of 1,100 people were recruited into this study and were collected by specialized research company. The data were collected by personal information using MBI(Mibyeong Index) and SF-12 (Short form-12) and were analyzed with SPSS (version 21.0) computer program, and included Pearson's chi-square test, ANOVA, Pearson's correlation coefficient, and multiple regression analysis. Results : The Mibyeong Index which represents abnormal symptom type showed significant difference for Mibyeong state (p<.001). In Total subject, fatigue, pain, low sleep quality and indigestion were found to be significant predictors of PCS(Physical Component Summary). In Healthy group, pain was found to be significant predictor of PCS. In MI 1 group, fatigue, pain, indigestion and anxiety were found to be significant predictors of PCS. In MI 2 group, fatigue, pain and low sleep quality were found to be significant predictors of PCS. In Total subject, fatigue, depression, anger and anxiety were found to be significant predictors of MCS (Mental Component Summary). In Healthy group, indigestion and anxiety were found to be significant predictors of MCS. In MI 1 group, depression and anger were found to be significant predictors of MCS. In MI 2 group, fatigue and depression were found to be significant predictors of MCS. Conclusions : The relationship between Quality of life and MBI changes according to Mibyeong state. We expect that this result could be contribute to health management of people in Mibyeong state.

• Journal of Korea Foundry Society
• /
• v.31 no.1
• /
• pp.11-17
• /
• 2011

The effect of CaO addition to AM60B Mg alloy on tensile properties has been investigated, with focus on strength and ductility at room and elevated temperatures. The 0.25-0.65wt% CaO added AM60B Eco-Mg diecastings were prepared by high pressure die casting using Buhler 1,450-ton cold chamber machine without $SF_6$ and $SO_2$ gases. The microstructures and tensile properties of each alloy were tested. The results show that the grains of AM60B are refined and the mechanical properties increase with CaO addition at room temperature. The improvement of strength and ductility is prominent at 0.45-0.55wt% CaO addition. Also, improved mechanical properties are maintained at elevated temperature of $150^{\circ}C$. CaO addition results in $Al_2Ca$ phase formation mostly on the grain boundaries. This phase leads to the refinement of grain structures and improvement of ductility as well as strength. The suppression of ${\beta}-Mg_{17}Al_{12}$ phase as well as the decrease of fracture surface porosity and other casting defects caused by melt cleanliness also contribute to the enhancement of mechanical properties of AM60B Eco-Mg at room and elevated temperature.

• Korean Journal of Health Education and Promotion
• /
• v.26 no.4
• /
• pp.71-81
• /
• 2009

Objectives: This study furthers the currents understanding of alcohol use disorders, stress, mental health status and suicide among Seoul citizens. This study is to identify differences according to socio-demographic variables and variables which affect stress, mental status and suicide for developing mental health programs. Methods: The study subjects using cluster-stratified sampling method were 1234 adults over 19 years old from 17 dong, S-Ku in Seoul City. A cross-sectional study with face-to-face interview was used to collect data. A questionnaire measuring socio-demographic variables, Symptom Checklist-90-Revised (SCL-90-R) and psychosocial wellbeing index-short form (PWI-SF) was utilized. Results: Three findings in this study were discussed: (1) The prevalence of problem drinking and alcohol dependence and AUDIT score were significantly higher among male, younger age, and high level of education and income; (2) AUDIT score were related with stress, all 9 symptoms of SCL-R and suicide plan; (3) Problem drinkers were more likely to have 2.5 times of anxiety, 3.0 times of hostility, and 2.4 times psychoticism than non alcohol problem drinkers. Alcohol dependence drinkers were more likely to have 1.9 times of high risk group of stress, 4.1 times of obsessive-compulsive, 4.7 times of anxiety, 5.5 times of hostility, and 2.3 times psychoticism than non alcohol dependence drinkers. Conclusion: The findings suggest that the future intervention of Mental Health programs should be carefully designed and tailored by socio-demographic variables.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.30 no.1
• /
• pp.72-78
• /
• 2016

In terms of power components which use environmentally-friendly dry air that can substitute SF6, there have been studies on the electrical properties of the solid insulation "spacer" for the purpose of securing dielectric strength as they become smaller. This study laminated solid insulation to keep the creeping distance the same in the dry air and investigated vertical surface discharge characteristics by shape. The three sheets of disk-type solid insulation(Bakelite) were laminated in a manner to keep the creeping distance the same. The lamination was categorized as follows: "Type A" in which the insulations with the same disk diameter were laminated; "Type B" in which the insulations whose middle disk diameter was large were laminated; and "Type C" in which the ones whose middle disk diameter was small were laminated. For a vertical surface discharge experiment, dry air was injected into the test chamber depending on the shape of the laminated solid insulation, and chamber pressure was adjusted in a range of 0.1-0.6MPa. As volume decreased, surface discharging voltage by unit volume increased. This was because of dielectric polarization according to the structural characteristics of the shape of lamination. The highest surface discharging voltage was found in "Type C."

• The Journal of Pediatrics of Korean Medicine
• /
• v.27 no.2
• /
• pp.1-10
• /
• 2013

Objectives The aim of this study was to explore the effect of parental attitude on the behavioral problems in children who visited the traditional Korean pediatrics clinic. Methods The subjects were consist of 190 outpatients ($56.6{\pm}12.9$ months) and their mother. The Behavior problems of children were measured with Korean version of Child Behavior Checklist for Ages 1.5-5 (K-CBCL1.5-5) while parental perception of child vulnerability, parent overprotection, parenting stress were measured by Child Vulnerability Scale (CVS), Parent Protection Scale (PPS), Korean-Parenting Stress Index-Short Form scale (K-PSI-SF), respectively. Correlation and multiple regression were conducted for the analysis. Results Significant correlations between child total problems score and child vulnerability (r=.272, p<.001), parent overprotection (r=.243, p=.001), and parenting stress (r=.597, p<.001) were reported. Multiple regression analysis revealed that the parenting stress (${\beta}$=.548, p<.001) was a major predictor for the child behavior problems rather than child vulnerability and parent overprotection. Conclusions It was shown that the parenting stress has a significant influence on the emotional and behavioral development of children. These results can be useful for improving clinical diagnosis and treatment in traditional Korean pediatrics.

• Safety and Health at Work
• /
• v.10 no.1
• /
• pp.39-46
• /
• 2019

Background: As of now, the impact of low back pain (LBP) and its chronic state, chronic low back pain (CLBP), on mental health-related quality of life (HRQOL) has never been investigated among police officers. The present investigation aims at studying this relationship using a biopsychosocial model. Methods: Between May and October 2014, a Web-based cross-sectional study was conducted among Quebec police officers (Quebec, Canada). Mental HRQOL was measured using the role emotional (RE) and the mental health (MH) domains of the SF-12v2 Health Survey. The impact of CLBP on mental HRQOL (as opposed to acute/subacute LBP or no LBP) was studied with a multivariate linear regression model. Results: Of the 3,589 police officers who participated in the study, 1,013 (28.4%) reported CLBP. The mean age of respondents was $38.5{\pm}8.7years$, and 32.0% were females. The RE (44.1/100) and MH (49.0/100) mean scores of the CLBP group were comparable with the scores found in populations suffering from cancer or heart diseases. Compared to officers without LBP, the presence of CLBP was significantly associated with lower RE (${\beta}$: -0.068; p = 0.003) and MH (${\beta}$: -0.062; p = 0.002) scores. These relationships were not found in the acute/subacute LBP group. Conclusion: Our results underscore how frequent CLBP is among police officers and how burdensome it is. Considering the importance of good physical and mental health for this occupational population, police organizations should be aware of this issue and contribute to the efforts toward CLBP prevention and management in the workplace.

• Nutrition Research and Practice
• /
• v.18 no.2
• /
• pp.257-268
• /
• 2024

BACKGROUND/OBJECTIVES: This study investigated the relationship between adherence to the Mediterranean diet among Korean baby boomers and their levels of psychosocial stress. SUBJECTS/METHODS: The study included 1,656 adults (889 men and 797 women) born between 1955 and 1963 who participated in the 2005-2006 survey of the community-based Korean Genome and Epidemiology Study (KoGES). The Mediterranean-type diet score (MTDS) was calculated from the semi-quantitative food frequency questionnaire (SQFFQ) data. The psychosocial stress levels were calculated using the psychosocial well-being indexshort form (PWI-SF). Logistic regression analyses were performed to analyze the association between the MTDS (tertiles) and the prevalence of high psychosocial stress by gender. RESULTS: The ranges of the MTDS tertile groups were T1 (20-33 points), T2 (34-37 points), and T3 (38-39 points) for men, T1 (20-33 points), T2 (34-37 points), and T3 (38-48 points) for women. In both men and women, the consumption of whole grains, potatoes, fruits, vegetables, legumes, and fish increased with higher MTDS, while the consumption of red meat and dairy products decreased (P for trend < 0.05). As MTDS score increased the intake of energy, fiber, vitamins, and minerals (P for trend < 0.05). Men in the highest MTDS tertile had a 41% lower odds ratio (OR) of high psychosocial stress compared with those in the lowest tertile (OR, 0.59; 95% confidence interval [CI], 0.38-0.91). Similarly, women in the highest tertile of the MTDS had a 39% lower OR of high psychosocial stress compared with those in the lowest tertile (OR, 0.61; 95% CI, 0.40-0.95). CONCLUSION: Promoting adherence to the Mediterranean diet among baby boomers may have a positive impact on reducing their levels of psychosocial stress.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.20 no.1
• /
• pp.88-100
• /
• 2018

Methane emissions from rice paddies are the largest source of greenhouse gases in the agricultural sector, but there are significant regional differences depending on the surrounding conditions and cultivation practices. To visualize these differences and to analyze their causes and characteristics, the methane emissions from each administrative district in South Korea were calculated according to the IPCC guidelines using the data from the 2010 Agriculture, Forestry and Fisheries Census, and then the results were mapped by using the ArcGIS. The nationwide average of methane emissions per unit area was $380{\pm}74kg\;CH_4\;ha^{-1}\;yr^{-1}$. The western region showed a trend toward higher values than the eastern region. One of the major causes resulting in such regional differences was the $SF_o$ (scaling factor associated with the application of organic matter), where the number of cultivation days played an important role to either offset or deepen the differences. Comparison of our results against the actual methane emissions data observed by eddy covariance flux measurement in the three KoFlux rice paddy sites in Gimje, Haenam and Cheorwon showed some differences but encouraging results with a difference of 10 % or less depending on the sites and years. Using the updated GWP (global warming potential) value of 28, the national total methane emission in 2010 was estimated to be $8,742,000tons\;CO_2eq$ - 13% lower than that of the National Greenhouse Gas Inventory Report (i.e., $10,048,000tons\;CO_2eq$). The administrative districts-based map of methane emissions developed in this study can help identify the regional differences, and the analysis of their key controlling factors will provide important scientific basis for the practical policy makings for methane mitigation.

• Korean Journal of Food Science and Technology
• /
• v.37 no.2
• /
• pp.183-188
• /
• 2005

Effects of co-solvent polarity, citric acid, pressure, temperature, run time, and co-solvent ratio on extraction of major flavonoids from Lonicera Flos were investigated using supercritical fluid $CO_{2}(SF-CO_{2})$. HPLC analysis revealed addition of pure methanol resulted in low extraction yield of major flavonoids, luteoloin (Lu), Quercetin (Qu), Apigenin (Ap). Under same condition, as co-solvent polarity increased, yields of major flavonoids increased gradually, At optimum co-solvent extraction condirion of 60% aqueous methanol (10%, v/v), yields of Lu, Qu, and Ap were 42.09, 28.18, and 3.49 mg/100 g, respectively. Addition of citric acid to 60% aqueous methanol gave higher, with addition of 1% citrie acid resulting in highest yields of 63.2 (Lu), 39.35 (Qu), and 5.79 (Ap) mg/100 g. Optimum extraction conditions of major flavonoids were 200 bar, $50^{\circ}C$, 60 min, and $CO_{2}$-methanol-water(20: 1.8: 1.2).