• 한국해양공학회지
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• 제25권6호
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• pp.66-71
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• 2011

Recently, the production of shipbuilding and offshore plant industries, with a trend toward large structures, has led to an increased use of high strength ultra-thick plates. The use of ultra-thick plates increases the welding tasks, and the welding process generates distortion and residual stress in the weldment because of the rapid heating and cooling. Welding distortion and residual stress in the welded structure resulte in many troubles such as deformation and life deterioration. In particular, the welding residual stress has an important effect on welding deformation, fatigue, buckling strength, brittleness, etc. The purpose of this study was to evaluate the residual stress at a multi-pass weldment using an experimental method for EH36 high-tension steel. In this experimental method, AIS3000 was used to measure the residual stress of a welded part, HAZ, and base metal; EPMA and XRD were used to study the material properties.

• 대한치과기공학회지
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• 제40권4호
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• pp.249-259
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• 2018

Purpose: This study aimed to investigate the relationship between dental technology students' life stress and smartphone addiction in order to detect smartphone over-users early, prevent them from getting addicted, and obtain basic data for creating a positive environment for academic achievement by using smartphone in a right way. Methods: The subjects of this study were university students at D University and G University in Daejeon Metropolitan City and Gangwon-do. A questionnaire survey was conducted to the subjects who understood the purpose of this study and participated in it from March 1 to June 10, 2018, and 243 were finally analyzed except 24 questionnaires without sufficient answers. Results: As a result of multiple regression analysis with variables, which were significant in univariate analysis, as independent variables, there were gender and smartphone dependency as general characteristics affecting the degree of smartphone addiction, and family relations and future problems among stress sub-factors were selected as significant variables. Conclusion : In the case of college students, they choose the smartphone as the easiest way to relieve stress because they lack the time and space to actually release stress. Therefore, club activities or on-campus and extra-curricular activities are recommended, and it needs to seek a way to get rid of stress by solving the cause of stress through counseling.

• Journal of Ginseng Research
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• 제32권2호
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• pp.150-154
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• 2008

Twenty five albino rats were divided into five groups for conducting this experiment. The first group was for positive control (Vitamin C, ascorbic acid), the second group was of Panax ginseng (10 mg/kg body weight) treated group after bio-activity assay, the third group was of mercuric chloride treated group (0.033 mg/kg body weight) based on calculating $LD_{50}$ 9.26 mg/kg body weight by probit analysis, the fourth group was of mercuric chloride (0.033 mg/kg body weight) followed by Panax ginseng (10 mg/kg body weight) and the fifth group was Panax ginseng (10 mg/kg body weight) followed by mercuric chloride (0.033 mg/kg body weight) treated group. The interval between intake of Panax ginseng and mercuric chloride was of 2 hours in groups, fourth and fifth respectively. Comparative free radical scavenging property of Panax ginseng was studied under three in vitro models (role model for calculating scavenging activity) viz. DPPH method (hydroxyl free radicals), Nitric oxide method (nitrile free radicals) and Lipid peroxidation (mercury free radicals).

• 근관절건강학회지
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• 제22권2호
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• pp.121-129
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• 2015

Purpose: This study was conducted to understand the relationships among freshman nursing students' academic stress, depression, and physical activity. Methods: In this descriptive study, Freshman students sampled from 4 nursing colleges were surveyed using a structured questionnaire on academic stress, depression and physical activity during the period from May to June, 2015. Results: A positive correlation was observed between academic stress and depression, but no correlation was found with physical activity. Of the subjects, 24.3% had a moderate or severe level of depression. Depression and physical activity were different according to exercise. Conclusion: The results of this study show the importance of reducing academic stress and depression for freshman nursing students. Thus, it is necessary to develop and apply depression prevention education programs to reduce academic stress and depression so that freshman nursing students lead to a healthy campus life.

• 한국학교ㆍ지역보건교육학회지
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• 제24권3호
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• pp.23-35
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• 2023

Objectives: The purpose of this study is to examine the marital status, drinking behavior, and mental health characteristics of alcohol consumers, and to explore the relationship between marital status and mental health among alcohol consumers. Methods: The research data utilized raw data from the 8th Korea National Health and Nutrition Examination Survey (2020), Second Round. A total of 3,713 participants were included in the final analysis. Data analysis was performed using the statistical software SPSS version 26.0. Results: The relationship between the study participants and mental health revealed that compared to those with a spouse, individuals who were divorced or separated had an odds ratio (OR) of 2.598 for 'depression' and an OR of 2.142 for 'suicidal thoughts'. In the case of 'stress perception', individuals who were divorced or separated had an OR of 3.434. In terms of gender, females had an OR of 4.867 for 'depression', an OR of 2.510 for 'suicidal thoughts', and an OR of 1.847 for 'stress perception', compared to males. Regarding age, the odds of 'depression' were 1.801 times higher in the 60 to 79 age group compared to the 18 to 39 age group. For smoking status, smokers had an OR of 2.812 for 'depression' compared to non-smokers. The OR for 'suicidal thoughts' was 3.047, and the OR for 'stress perception' was 1.463. However, the relationship between mental health and binge drinking frequency and quantity of alcohol consumed in a single session was not significant. Conclusion: The divorced, separated, or bereaved groups may be vulnerable to 'depression,' 'suicidal ideation,' and 'stress.' Therefore, there is an expectation to explore strategies for the development and enhancement of community-based mental counseling and health education support programs, aiming to improve the mental well-being and quality of life of individuals and the local community.

• 한국학교ㆍ지역보건교육학회지
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• 제23권1호
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• pp.1-16
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• 2022

Background & Objectives: Self-rated health has been widely used to evaluate health status and accepted as a subjective measurement of quality of life. This study aimed to analyze the associations between self-rated health, health promotion behaviors, and mental health factors and suggest the approaches to improve health status among university students. Methods: Two thousand six hundred seventy-seven students who had stayed at dormitories on campus participated in the DU health survey by self-reported questionnaire from April 10 to 14, 2017. Multivariate logistic regression analysis was performed to estimate the odds ratios and 95% confidence intervals of association of self-rated health with health-related factors among male and female students. Results: 38.6% of the respondents reported good self-rated health. Male and first-year students were more likely to report good self-rated health than female and third-year students. There were significant differences in sex, grade, health problems, BMI, sleeping hours, eating breakfast, consumption of fruits and vegetables, physical activity (regular walking, strength exercise, moderate exercise, vigorous exercise), perceived stress, depression, and suicide thought (p<0.05). Conclusion: Although health promotion programs for university students are essential to support their adaptation to campus life and academic achievement, evidence-based health programs to encourage their participation are still insufficient. Therefore, it should establish a campus-based health policy and develop health promotion programs to increase self-rated health levels and prevent mental health problems for university students.

• 지역사회간호학회지
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• 제26권2호
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• pp.169-177
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• 2015

Purpose: Previous studies focused on the negative effects of Internet use such as obesity, depression, and addiction. However, few studies investigated whether the Internet use for an appropriate time has positive effects on adolescents' health. Thus, the purpose of the study was to examine the dose-response relationship between Internet use for non-academic purposes (NAP) and happiness/stress in adolescents. Methods: This study used data from the 2013 Korea Youth Risk Behavior Web-Based Survey. A total of 72,435 adolescents were included. Rao-Scott ${\chi}^2$ and multiple logistic regression were conducted. To test the dose-response relationship, this study examined how happiness/stress changed with increase in the time of Internet use for NAP. Results: After controlling for general characteristics, the odds ratios for being unhappy and stressful were lowest in adolescents using the Internet for NAP for more than 0 hour and less than an hour a day. Interestingly, students who did not use the Internet for NAP had a significantly higher risk of being unhappy/stressful than those using for more than 0 hour and less than an hour a day. Conclusion: Internet use for NAP for more than 0 hour and less than an hour a day has positive effects on happiness/stress in adolescents.

• 대한화장품학회지
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• 제44권2호
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• pp.133-139
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• 2018

화학적으로 손상된 모발은 모발 자체의 물리적 특성이 약해져서 일상생활 중에 외부 자극에 취약하다. 본 연구의 목적은 모발 케라틴 단백질간의 화학적 결합이 모발의 인장강도를 회복이 반복적인 빗질 하에서 더 이상의 모발 악화를 방지하는지 여부를 결정하는 데 있다. 손상된 모발은 펌 시술을 통해 얻었다. 펌 손상 모발을 관능성 가교제인 3-aminopropyltriethoxysilane (APTES)을 이용하여 실란 커플링 및 카르보디이미드 반응을 통해 모발 내부에 가교 결합이 형성되도록 처리하였다. 인장 강도, 영률 및 고원 응력(plateau stress)을 포함한 물리적 특성을 측정하여 내부 가교 결합의 효과를 확인하였고, 가교 결합의 존재는 Fourier transform infrared (FT-IR) 분광법으로 확인하였다. 모발 절단 및 갈라짐의 정도는 건조 상태 모발의 반복적 빗질 시험으로 평가하였다. 결과적으로 화학적으로 손상된 모발의 물리적 성질은 내부 가교 결합으로 회복되었다. APTES의 실란 커플링 및 카르보디이미드 반응의 결합은 FT-IR 스펙트럼으로 확인하였다. 열을 가하면서 반복적으로 빗어 낸 후 모발의 절단 및 갈라짐 방지가 확인되었다. 인간의 모발은 펌 시술을 포함한 화학적 손상으로 약화될 수 있으므로 이러한 특성을 복원하는 것은 헤어 케어 업계의 주요 과제다. 본 연구에서는 화학적 결합을 통해 손상된 모발의 내부에 가교 결합 형성이 모발의 건강을 회복시키는 강력한 방법이 될 수 있음을 시사한다.

• Design & Manufacturing
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• 제14권4호
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• pp.1-10
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• 2020

The seal plays a role in preventing oil leakage when the lip and the rotating shaft come into contact with the fluid and air pressure. Recently, micro dimples or micro pockets are processed and used on the lubrication surfaces of thrust bearings, mechanical bearings, and piston rings. Compared to a smooth surface, micro dimples reduce friction and increase the life of parts. This paper analyzed various kinds of micro dimple shapes on the sealing surface, i.e. circle, rectangle, triangle, and trapezoid. For this purpose, Introduced the design of experiments to work out a micro dimple configuration, unlikely to be damaged from cracks and low in contact stress. As a result, the triangular dimple showed the best results. Optimal factors were dimple size 0.15 mm, dimple depth 0.0383 mm, dimple density 40%, and the maximum equivalent stress was 9.1455 MPa, and the maximum contact pressure was 9.6612 MPa. This paper analyzed the optimal shape of dimples by finite element analysis. As a research project, experiments and comparative analysis of micro dimple shapes are needed.

• 한국아동복지학
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• 제40호
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• pp.229-253
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• 2012

본 연구는 우리나라 청소년의 학업스트레스와 자기통제의 관계에서 자아존중감의 조절효과를 검증하는데 목적이 있다. 이를 위하여 자기통제 힘 모형을 예방과학적 관점으로 조명하여 연구의 분석틀로 설정하였다. 연구문제 및 가설을 검정하고자 한국청소년패널조사(KYPS)의 중학교 2학년 패널 4차년도 자료를 활용하였으며, 일반 고등학교 2학년에 재학 중인 2,169명의 청소년을 연구참여자로 선정하였다. 분석 결과, 학업스트레스가 자기통제에 미치는 영향에 대하여 자아존중감의 조절효과가 확인되었다. 즉, 학업스트레스는 자아존중감의 수준과 상관없이 청소년의 자기통제를 저하시켰다. 그러나 자아존중감이 높은 청소년의 경우, 자아존중감이 낮은 청소년에 비해 더 높은 수준의 자기통제를 가지고 있었으며, 학업스트레스가 높은 상황에서 자아존중감이 학업스트레스가 자기통제에 미치는 부정적인 영향력을 완화시키고 있었다. 이러한 연구결과에 기반하여 함의를 논하였다.