• Advances in nano research
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• v.9 no.3
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• pp.147-156
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• 2020

This research is related to nonlinear stability analysis of advanced microbeams reinforced by Graphene Platelets (GPLs) considering generic geometrical imperfections and thermal loading effect. Uniform, linear and nonlinear distributions of GPLs in transverse direction have been considered. Imperfection sensitivity of post-bucking behaviors of the microbeam to different kinds of geometric imperfections have been examined. Geometric imperfection is first considered to be identical as the first buckling mode, then a generic function is employed to consider sine-type, local-type and global-type imperfectness. Modified couple stress theory is adopted to incorporate size-dependent behaviors of the beam at micro scale. The post-buckling problem is solved analytically to derive load-amplitude curves. It is shown that post-buckling behavior of microbeam is dependent on the type geometric imperfection and its magnitude. Also, post-buckling load can be enhanced by adding more GPLs or selecting a suitable distribution for GPLs.

• Journal of Welding and Joining
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• v.32 no.5
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• pp.13-20
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• 2014

A brief overview is given of the corrosion and hydrogen diffusion behaviors of high strength pipe steel in sour environment. Firstly, hydrogen adsorption and diffusion mechanism of the pipe steel is introduced. Secondly, the effect of iron sulfide film precipitated as a result of the corrosion reaction on the steel surface on hydrogen reduction reaction and subsequent hydrogen permeation through the steel is discussed. Moreover, the hydrogen diffusion behavior of the pipe steel under tensile stress in both elastic and plastic ranges is reviewed based on a number of experimental permeation data and theoretical models describing the hydrogen diffusion and trapping phenomena in the steel. It is hoped that this paper will result in significant academic contributions in the field of corrosion and hydrogen related problems of the pipe steel used in sour environment.

• Food Science and Preservation
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• v.30 no.5
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• pp.785-796
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• 2023

The aim of this study was to elucidate chemical structures and rheological properties of arabinogalactans (AGs) isolated from three legumes including black gram (BG), great northern bean (GNB), and California small white bean (CSWB). The ratio of galactose to arabinose (G/A) in three legumes increased in the order of BG > GNB > CSWB. The rheological measurements of 1-5% (w/v) AG solutions revealed Newtonian and non-Newtonian flow behaviors. BG exhibited yield stress, indicating plastic behavior. Small-amplitude oscillatory tests indicated viscoelastic properties of BG, GNB, and CSWB ranging from solid-like, paste-like, and liquid-like behaviors, respectively. Small-strain oscillatory tests were conducted to assess the structure recovery of the AGs after pre-shearing. G" values of BG and GNB increased, but those of CSWB remained constant after shearing. These results suggest that the chemical structures of the AGs, particularly their G/A ratios, influence their rheological properties.

• Human Ecology Research
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• v.52 no.5
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• pp.495-507
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• 2014

The purpose of this study was to explore the general tendencies of major variables and sex differences and to analyze the variables that affect delinquency and aggression. The protective factors considered in this study included parental education participation, parental supervision, and peer attachment, and the risk factors were academic stress and delinquency experiences of peers. The main results of this study are as follows: firstly, academic stress and parental education participation was slightly low, but parental supervision was high. Further, peer attachment showed a very high score. Delinquency experiences of peers, delinquency, and aggression of adolescents were extremely low. Secondly, the correlation of parental education participation, parental supervision, and peer attachment was negatively related to adolescent delinquency, but the delinquency experiences of peers were positively related to adolescent delinquency. The same results were obtained in the case of adolescent aggression. Further, academic stress was negatively related to adolescent aggression. Finally, hierarchical regression revealed that the variables explaining the juvenile delinquency were parental education participation, peer attachment, and delinquency experiences of peers. Adolescent aggression was explained by sex, academic stress, parental education participation, and the delinquency experiences of peers. In particular, more attention is needed for girls. Various interventions should be provided to prevent problem behaviors.

• Korean Journal of Health Education and Promotion
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• v.25 no.3
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• pp.59-75
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• 2008

Objectives: The purpose of this study was to identify the stages of change distributions for nine major health behaviors among poor children in underserved area, and to provide basic information for developing specific objectives and strategies for health education program. Methods: The health behavior data were obtained with a self-administered questionnaire and analysed for 3,081 poor children in 106 local children's centers nationwide. Stages of change classification were based on self-reported responses to five statements. The health behaviors included were balanced diet, safety behavior (helmet and protective device use while riding), regular exercise, smoking, alcohol use, drug use, sleep pattern, weight management and stress management. Results: Poor children were more likely in precontemplation and less frequently in action and maintenance stages for a safety behavior. 33.1% of respondents were precontemplators, 29.9% contemplators, and 6.5% in preparation stage. Only 4.3% and 9.6% were in action and maintenance stages, respectively. Gender differences were apparent. Boys were more likely to be precontemplators for nine health behaviors. Children from the lowest socioeconomic status and disrupted family were more likely to be in precontemplation for weight management and exercise behaviors. Children living with both parents were more likely to be in the action and maintenance stages for nine health behaviors. Stages of change for balanced diet and smoking were significantly related with those for other eight health behaviors. And the stage of exercise adoption was found to be significantly related with those for other seven health behaviors. Conclusion: Safety education must receive high priority in health education program for low income children. Balanced diet smoking cessation and regular exercise could be a possible gateway behavior toward healthier lifestyle practices.

• Journal of Korean society of Dental Hygiene
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• v.10 no.4
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• pp.595-605
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• 2010

Objectives : A precedent research has documented that occupational stress is closely associated with increased the risk of fatigue and decreased in job satisfaction. This study was conducted in an effort to assess the relationship of occupational stress to self-perceived fatigue and job satisfaction by using job strain model. Methods : The number of respondents was 122 dental hygienist who work in dental clinic and period of the investigation was July 2009 through september 2009. A structured questionnaire was employed to evaluate the participants' sociodemographics, job-related factors, health-related behaviors, occupational stress, job satisfaction and self-perceived fatigue. Occupational stress and self-perceived fatigue were assessed using the Korean Occupational Stress Scale-Short form (KOSS-SF) and the Multidimensional Fatigue Scale (MFS), respectively. Results : In job strain model, the ratio of Q2(High Strain Job) group that more susceptible to disease by stress than other group was 16% and the proportion of high fatigue group(Q3, Q4 group) and low job satisfaction group(Q3, Q4 group) was 48%, 45% respectively. In logistic regression analyses, a High Strain Job group was associated with higher odds of react factor(fatigue, job satisfaction) and the odds was down by 3.3%~7.5% after adjustment for age, smoking, alcohol drinking, regular exercise. So the effective strategy for fatigue, job satisfaction reduction for dental hygienist requires additional program focusing on innovated work environment that provide a enough leisure time and exercise program considering the personality traits. Conclusions : The results of this study suggest that occupational stress is a determinant predictor of self perceived fatigue and job satisfaction. Thus, a stress management program for the reduction of occupational stress, and the promotion of dental hygienist impact assessment health and quality of life is strongly recommended.

• Journal of Korean Academy of Rural Health Nursing
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• v.9 no.2
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• pp.59-70
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• 2014

Purpose: The present study was to done ascertain variables related to health-related quality of life (HRQOL) and their related factors in elders from urban or rural areas. Methods: Data were collected from raw material of the 2009 community health survey. Participants were 2,140 elders. Health related quality of life (HRQOL) was measured using EQ-5D. Data were analyzed with SPSS 13.0. Results: Mean EQ index score for urban elders was $0.78{\pm}0.23$, Mean EQ index score for rural elders was $0.82{\pm}0.16$. Rural elders had significantly higher EQ-5D index value compared to urban elders. The urban elder HRQOL model accounted for 33.6% of the variance due to depression, age, stress perception. The rural elder HRQOL model accounted for 23.5% of the variance due to exercising walking, skipping breakfast, depression in that order. In comparison, depression, skipping breakfast, livelihood, arthritis, stress perception, hours of sleep and age are strongly associated with HRQOL in both groups. Conclusion: Results indicate that significant differences in HRQOL between elders from the two areas and thus, confirm claims that welfare services for elders should be provided with consideration of the different needs of elders in the two areas, and in particular for addressing depression in elders.

• Journal of the Korean Society of Food Culture
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• v.10 no.1
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• pp.19-28
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• 1995

The relationship of obesity and related behaviors was analyzed among 361 primary school children, 4th and 5th grade, in one of private school in Seoul in July 1994. Compared to 1985 Korean Children's Growth Standard, the surveyed children have shown remarkable growth, which is the secular trend in growth of Korean children accompanied with rapid economic growth. But the relative incremental weight was far larger than that of height and this trend was more evident among children over 50th percentile, which shows a wide prevalence of obesity of the surveyed children. By WLI index, 15% of the children was overweight and 13% was obese. The higher the WLI, the more frequent and stronger stress they had. The nutrition knowledge score of obese children was higher compared to others. They were especially sensitive to their physical fitness but many normal or underweight-children also experienced stress due to their body weight and have tried to lose weight by incorrect methods. On the other hand many obese children thought they were optimal or underweight. These results reasserts the importance of nutrition education focused on children aheading puberty. They need to know the correct degree of obesity and to get appropriate education through teachers, dietitians, parents and doctors. The findings of this study could be applied to a nutrition implementation policy to ensure better physical fitness of children aheading puberty in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4694-4702
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• 2012

The purpose of this study was a descriptive research that identified the levels of health-promoting behaviors, previous related behavior, perceived benefits/barriers, self-efficacy, and social support. In addition, it was to establish the relations among the variables, and determine the factors affecting the health-promoting behaviors. Study participants were 311 middle aged between 55-64 in urban areas, and the data were collected through self-reported structured questionnair. According to the results, the mean score for the levels of health-promoting behaviors of the late middle aged was 2.64. Also, among the variables related to health-promoting behaviors, perceived benefits were the highest score (30.7), and perceived barriers were the lowest one (2.08). Meaningful positive correlations were found among health-promoting behaviors and previous related behavior, social support, perceived benefits, and self-efficacy, but perceived barriers showed weakly negative correlations. In addition, the factors affecting health promoting behaviors were revealed in order as following: Previous health related behavior(${\beta}$=.35, p<.001), perceived benefits(${\beta}$=.32, p<.001), social support(${\beta}$=.28, p<.001), and life satisfaction(${\beta}$=.13, p<.001), and this model's explanatory power was 68.8%(F=166.71, p<.001). Based on the findings from the study, in order for the late middle aged to have a well-being old age, an health promoting education program including exercises and stress management should be provided to maintain and improve proper health promoting behaviors. The network with the same age groups also should be supported to share useful information and back up one another.

• Journal of Preventive Medicine and Public Health
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• v.52 no.2
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• pp.92-100
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• 2019

Objectives: Young adulthood represents a critical developmental period during which the use of tobacco may begin or cease. Furthermore, differences in smoking behaviors between younger (aged 18-24 years) and older (aged 25-34 years) young adults may exist. This study aimed to characterize patterns related to current smoking in younger and older young adults. Methods: This study used data acquired from the Sixth Korea National Health and Nutrition Examination Survey conducted from 2013 to 2014. A total of 2069 subjects were categorized as younger (712 subjects) and older (1357 subjects) young adults. The chi-square test was used to assess the relationships between smoking status and socio-demographic, health-related, and smoking-related factors. Multivariable logistic regression models were constructed to assess the factors affecting current smoking in these age groups. Results: The current smoking prevalence was 18.3% among the younger young adults and 26.0% among the older young adults. Sex, education level, occupation, perceived health status, alcohol consumption, and electronic cigarette use were related to current smoking in both age groups. Secondhand smoke exposure at home and stress levels showed significant relationships with smoking in younger and older young adults, respectively. Conclusions: Strong correlations were found between the observed variables and smoking behaviors among young adults. Determining the factors affecting smoking and designing interventions based on these factors are essential for smoking cessation in young adults.