• Journal of Powder Materials
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• v.16 no.4
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• pp.285-290
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• 2009

HDDR treated anisotropic Nd-Fe-B powders have been widely used, due to their excellent magnetic properties, especially for sheet motors and sunroof motors of hybrid and electric vehicles. Final microstructure and coercivity of such Nd-Fe-B powders depend on the state of starting mother alloys, so additional homogenization treatment is required for improving magnetic properties of them. In this study, a homogenization treatment was performed at $900\sim1140^{\circ}C$ in order to control the grain size and Nd-rich phase distribution, and at the same time to improve coercivity of the HDDR treated magnetic powders. FE-SEM was used for observing grain size of the HDDR treated powder and EPMA was employed to observe distribution of Nd-rich phase. Magnetic properties were analyzed with a vibrating sample magnetometer.

• Nutrition Research and Practice
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• v.9 no.4
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• pp.411-419
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• 2015

BACKGROUND/OBJECTIVES: This study analyzed factors affecting consumption frequencies of vegetables and fruits in Korean adolescents. SUBJECTS/METHODS: Consumption frequencies of vegetables and fruits, general characteristics, meal, health, and other variables were analyzed for a total of 147,047 adolescents who participated in the KYRBWS (Korea Youth Risk Behavior Web-based Survey) conducted in 2006 and 2011 by the Korea Centers for Disease Control and Prevention. RESULTS: Consumption frequencies of vegetables and fruits more than once a day significantly decreased in 2011 compared to 2006 based on Chi-square test conducted for every factor employed in the study. Analysis of factors showed that consumption frequencies of vegetables and fruits were reduced in both study years as subjective income decreased, whereas intake frequencies increased with mother's education level and reduction of adolescent stress level. CONCLUSIONS: In general, consumption frequencies of vegetables and fruits decreased in 2011 compared to those in 2006. Thus, future research needs to improve dietary guidelines for nutrition education in order for students to recognize the importance of food consumption and necessity of increasing daily serving sizes of vegetables and fruits for their balanced consumption.

• Research in Community and Public Health Nursing
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• v.29 no.1
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• pp.33-40
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• 2018

Purpose: The purpose of this study was to identify factors associated with intermittent and light smoking among Korean high school students. Methods: In this cross-sectional study, we employed secondary data from the 2015 Korea Youth Risk Behavior Web-Based Survey, and used the biopsychosocial model as a framework. The analysis was performed using the data of 2,851 high school students who smoked. We defined intermittent and light smoking as smoking on 1 to 29 days in a 30-day period and no more than 10 cigarettes per day. A logistic regression analysis using the complex samples procedure was conducted. Results: Among all the participants, 1,231 (43.2%) were intermittent and light smokers. Factors significantly predicting intermittent and light smoking were gender and grade (biological factors); subjective stress (psychological factor); and mother's smoking, sibling's smoking and academic achievement (sociocultural factors). Conclusion: In smoking cessation programs, health care providers both at school and in the community should consider the unique biological, psychological, and sociocultural characteristics of intermittent and light smoking behavior among high school students.

• Journal of the Korean Home Economics Association
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• v.37 no.6
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• pp.139-153
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• 1999

The study was initiated to research on the school uniform preference, satisfaction according to demographic factors and clothing involvement. Data were administered to 513 adolescence in middle school student living in Sunchon. For analysis of the data, frequencies, percentage, means, standard deviation, ${\chi}^2$-test, one-way anova, and duncan's multiple range test were employed. The results of this study can be summarized as follows. 1) school uniform satisfaction were shown to have the significant differences according to sex, father's occupation and education, income, the type of school. 2) school uniform preference were shown to have the significant differences according to sex, parent's education, father's occupation, income, social stratification, the type of school. 3) clothing involvement were shown to have the significant differences according to mother's education, income, social stratification. 4) school uniform preference were shown to have the significant differences according to level of clothing involvement. The higher was clothing involvement, the higher was preference to 'no static electricity', 'fashionable one' and 'one with fine air permeability and water absorbency' of school uniform.

• Korean Journal of Child Studies
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• v.7 no.2
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• pp.33-53
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• 1986

The purpose of this study was to investigate parents' perceptions of parental role responsibilities and to examine how these are influenced by parent's sex and child's sex. A total 320 subjects who have preschool or elementary school children (fathers, 151: mother 169) were randomly selected from nursery school, kindergarten, elementary schools in Seoul. The Perceptions of Parental Role Responsibilities Scales (PPRS) of Gilbert and Hanson (1983) was translated and supplemented by the investigator and employed in this study. The obtained data were analyzed by Two-way MANOVA, Univariate F-test, and One-way MANOVA. The results of this study showed that: 1. In Cognitive Development (CD), Handling of Emotions (HE), Social Skills (SoS), Personal Hygiene (PhH), Health Care (HC), Material (M), Meeting the Emotional Needs (EN) and Child Care (CC), mothers perceived higher parental role responsibilities than fathers did, and in Physical Health (PhH), fathers were higher than mothers. 2. In HE, Survival Skills (SuS), and M, mothers perceived higher parental role responsibilities toward daughters than sons. 3. In HE, SuS, M, EN and CC, fathers perceived higher parental role responsibilities toward daughters than sons, and they were higher in SoS and PhH, toward sons than daughters.

• Child Health Nursing Research
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• v.24 no.2
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• pp.128-137
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• 2018

Purpose: To investigate factors that may affect the method of feeding among preterm infants at 4 weeks after discharge. Methods: This study included 222 mother-infant dyads born before a gestational age of 37 weeks. The feeding method and general medical characteristics of the participants were assessed at 4 weeks after discharge using a structured questionnaire. Multinomial logistic regression analysis was used to examine which factors were associated with breastfeeding at home. Results: Of the 222 infants who qualified for the study, 71 (32.9%) continued to receive breastmilk at 4 weeks post-discharge. Multinomial logistic regression analysis showed that breastfeeding at 4 weeks post-discharge was associated with higher breastfeeding self-efficacy, vaginal delivery (experience), direct breastfeeding in the neonatal intensive care unit (NICU), gestational age between 30 and 34 weeks, and breastmilk consumption in the NICU. The following factors were associated with mixed feeding at 4 weeks post-discharge: being employed, having higher breastfeeding self-efficacy, and direct breastfeeding in the NICU. Conclusion: NICU nurses should provide opportunities for direct breastfeeding during hospitalization and support breastfeeding to enhance breastfeeding self-efficacy. These factors may help to ensure the continuation of breastfeeding after discharge. Moreover, factors that affect breastfeeding should be considered when providing interventions.

• Smart Structures and Systems
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• v.18 no.5
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• pp.1063-1085
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• 2016

Taking advantage of the high sensitivity and long-distance detection capability of acoustic emission (AE) technique, this paper focuses on the crack detection in rail head, which is one of the most vulnerable parts of rail track. The AE source location and noise cancellation were studied on the basis of practical rail profile, material and operational noise. In order to simulate the actual AE events of rail head cracks, field tests were carried out to acquire the AE waves induced by pencil lead break (PLB) and operational noise of the railway system. Wavelet transform (WT) was first utilized to investigate the time-frequency characteristics and dispersion phenomena of AE waves. Here, the optimal mother wavelet was selected by minimizing the Shannon entropy of wavelet coefficients. Regarding the obvious dispersion of AE waves propagating along the rail head and the high operational noise, the wavelet transform-based modal analysis location (WTMAL) method was then proposed to locate the AE sources (i.e. simulated cracks) respectively for the PLB-induced AE signals with and without operational noise. For those AE signals inundated with operational noise, the Hilbert transform (HT)-based noise cancellation method was employed to improve the signal-to-noise ratio (SNR). Finally, the experimental results demonstrated that the proposed crack detection strategy could locate PLB-simulated AE sources effectively in the rail head even at high operational noise level, highlighting its potential for field application.

• Journal of Family Resource Management and Policy Review
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• v.9 no.4
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• pp.1-19
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• 2005

This study has attempted to investigate the time use of the elementary school students and their satisfaction levels by their general characteristics for the educational guidance. The sample of this study consisted of 387 elementary school students on Jeju Island who are in the fifth or sixth year. The data were analysed by frequency, percentage, mean, t-test, ANOVA and Duncan's test. The major results of this study were as follows; The results of this study showed that the students spent much time for studying including extra programs as like their ages. Also, their leisure time focused on watching TV or doing computer. The levels of satisfaction according to the time use were slightly high although their time allocation was not various. The time use of the students and their satisfaction levels were significantly affected by the general family situation related to parents as well as their own characteristics. The variables such as the student's sex, parent's educational level, whether the mother is employed or not, and monthly allowance were important to result in the differences of the time use and satisfaction levels among the students. The leisure time was strongly related with the satisfaction levels.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.8 no.1
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• pp.57-69
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• 1997

Objective：At the present time in Korea, for a considerable proportion of children and adolescent, delinquent behavior and violence has become as a way of life in their lives and a major social problem issue as well. The contributing factors to this problem were assumed to be the negative interaction between family environment and character of adolescent. The purpose of this study is to search the relationship between these constructs and juvenile delinquency. Method：Data were collected through questionnaire survey over a period of 2 months. Subjects served for this study consisted of 1,863 adolescents including 657 delinquent adolescents and 1,206 student adolescents in Korea, sampled from Korean student population and delinquent adolescent population confined in juvenile corrective institutions, using proportional stratified random sampling method. Their age ranged between 12 and 18 years. Data were analysed by IBM PC using SAS program. Statistical methods employed were Chi-square and principal component analysis. Results：The results of this study were as follows：Inconsistency by parental child rearing patterns tended to affect delinquent behavior among delinquent adolescents. On the other hand, adolescent students were consistently reared by their parent with democratic, flexible, trusting their children and reward-oriented attitudes. In comparison of both parents in the degree of influence on their children, it was revealed that paternal child rearing pattern was more influential on their children’s behaviors than maternal’s. The psychological instability of family, disharmonious parent-child relationships tended to be contributing to delinquent behavior among delinquent adolescents. Especially, It was an interesting finding that student’s mother is the higher employed than delinquent’s mother. However working mother was more prevalent in the student’ adolescents than in student adolescents in previous studies. The delinquent adolescents have more depressive trend, more complaints of psychosomatic symptoms, the higher degree of need frustration, the more maladaptive and antisocial personality pattern than student adolescents. Conclusion：Recently, many studies on association between family factor, character of adolescent and juvenile delinquent behavior have produced relatively consistent results. This study showed that family environment and character trait of adolescent also were linked with delinquent behavior such as smoking, drinking, runaway and physical assaults etc. The results of this survey may provide impetus for future speculation and study of correlation or reciprocal interaction between family factor, character trait of adolescent and delinquent behavior during adolescence and beyond.

• Journal of Korean Public Health Nursing
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• v.8 no.2
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• pp.101-113
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• 1994

Maternity means all the women who are capable to conceive. In the aspect of health and medical care. however. it means the women who are now in pregnancy or have already given birth to a baby or are in a period of being recoverd from physiological changes occurred by pregnancy. According to the rapidly changing social structure. both the Quality and Quantity of the capacity of childbirth experienced by women are changing. Our society. having established a great economical growth by virtue of the highly developing and growing industrialization and urbanization. stimulates the women's advance into society and thereby increasing the number of employed women. When the women's participation in society is increased. their age of marriage is also affected. Which means there are a decrease of the capacity of childbirth in terms of quantity and a trend for women to have less children and to deliver a baby in their old age in terms of quality. On the contrary. since the number of multipara who want to have a baby in their old age is increasing. as a counter functional effect to the political project of decrease of a birth rate. concern has been focussed on childbirth in old age in the present study. And also such kind of the childbirth may be danger to the health of both mother and baby. Therefore the present study intended to provide some basic data of health education in the part of the health management of both mother and baby in the general hospital. based on understanding the realities of childbirth in. old age and things related to them. To achieve such a purpose of the present study. an analytical study by means of SPSS. was done using the data of 269 clinical records on both the newborn .babies and their mothers who had been supported by public general hospitals located in Seoul for 3 years from Jan. 1. 1991 to Dec. 31. 1993. Some significant results from the analytic study are as follows: 1. It appeared that the average age of normal. natural delivery was 33.8 years old and the average age of delivery through the cesarean operation was 35.4 years old. 2. It appeared that danger factors to childbirth women were types of the delivery and placental extrusion and danger factors to newborn babies are not so outstanding. 3. It appeared that the variables of the childbirth capacity which showed a significant difference according to each age group of women were the number of pregnancy. number of still birth, and number of existing children. That is. the age group of 'more than 35 years' had more frequency of experience In all 3 variables than the age group of 'less than 35 years'. 4. It appeared that the variables of the childbrith capacity which showed a significant difference a according to the sex of a newborn baby were number of pregnancy, number of still birth, and number of existing children. That is, the age group of 'more than 35 years' had more frequency of experience in all 3 variables than the age group of 'less than 35 years'. 5. It appeared that the health index of newborn babies which showed a significant difference was only 5 minute APGAR. That is, the health index 9.46 in the age group of 'more than 35 years' was less than an index of 9.72 in the age group of 'less than 35 years'. 6. Since a counter correlation of -0.10, as Pearson Correlation Coefficient, was showed between the age of childbirth mothers and the weight of newborn babies, it indicated that the higher age of childbirth woman, the lesser the weight of newborn baby. 7. It appeared that the number of women who had confirmed the sex of their baby before their delivery were 45 women, $67.2\%$ of total 67 women who had delivered a baby. and the expected sex by women in childbed was male with $73.1\%$ of total childbirth women expecting male birth and with their expression of feeling of female delivery. very regretful' by $39.3\%$ of total childbirth women. The results as shown above may indicate that instead of the possibility of danger to both the mother delivering a baby in old age and the baby delivered, the expectation of getting a son motivates childbirth in old age. As a conclusion, in a dimension of general hospital as well as national reform. it is required that a program of health education for childbirth in late maternal age have to be developed in the part of the health management of both mother and baby in the near future.