• Korean Journal of Materials Research
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• v.23 no.4
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• pp.250-254
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• 2013

In order to increase the toughness of ZTA(zirconia toughened alumina) ceramics, the present study focused on rearrangement and densification of particles according to the particle size of the parent material. When rough alumina was used for production of ZTA, densification behavior was observed in the specimen sintered at a temperature over $1550^{\circ}C$. However, it was found that the densification behavior was occurred in the specimen sintered at $1450^{\circ}C$ when fine alumina powder was used. High relative density exceeding 98% was obtained when fine alumina powder was mixed with 15 wt% of 3Y-TZP and sintered at $1600^{\circ}C$. Also, a hardness of 1820.2 Hv was obtained when a specimen containing 10 wt% of 3Y-TZP was sintered at $1600^{\circ}C$. In the case of 3Y-TZP containing rough alumina powder that had been sintered the hardness value was around 1720.3 Hv. It was predicted that an improved toughening effect in ZTA could be achieved by using finer alumina powder as the parent material.

• Journal of Families and Better Life
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• v.29 no.5
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• pp.121-140
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• 2011

The purpose of this study is to understand how the economic conditions and needs of single-parent families are different between single-mother and single-father families, and also how they are dependent on household composition. The data for this study were drawn from the 1st Korea Welfare Panel Study and analyzed by frequencies, means, ${\chi}^2$, t-test, F-test, and logistic regression with the STATA 9.1 program. The major findings are as follows: (1) Single-parent families are more likely to live in a three-generation household than married couple families. (2) The composition of a three-generation household of single-parent families is affected by sex, age, education, type of marital disruption, the type of employment of single parents and the age of the last-born child. (3) The income-to-needs ratio is not significantly different depending on the sex of the single parents and their household composition. However, material hardship is significantly low in three-generation household single-parent families. (4) There are differences between three-generation single-parent families and independent single-parent families in income sources: The ratio of public transfer to total incomes is higher in three-generation households than independent households, while the ratio of private transfer to total incomes is higher in independent households.

• Korean Journal of Human Ecology
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• v.20 no.4
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• pp.745-757
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• 2011

The purpose of this study was to explore status of mathematical interactions between parent and child and use of mathematical materials at home. For this purpose, questionnaires were developed. The framework of the questionnaires consisted of mathematics education content domains. 276 parents(4-5 year old children) in J Province responded to the questionnaires, which were analyzed according to the level of home income, the mother's work conditions and the mother's level of education. The results were as follows: First, between parent and child mathematical interaction at home showed a 2.84 score in average and frequency of mathematical interaction expressed in the domains of 'Understanding of regularity', 'Measurement', 'Growing number sense', 'Space and shapes', 'Organizing data and showing results'. The domains of 'Growing number sense', 'space and shapes', and 'measurement' showed significant difference only by mother's level of education. The higher the mother's level of education, the more frequent the mathematical interaction between parent and child. Second, the use of mathematical materials showed an average score of 1.18, which means mathematical materials were practically not used at home. Also, the use of mathematical materials showed a slightly significant difference when measures against the levels of home income and the mother's level of education. The results showed a significant difference in parent-child mathematical interactions, and the possession and use of mathematical materials when measures against by level of home income and the mother's work conditions. Therefore, the results of this study suggest that the parent education program for mathematical interaction to apply at home and mathematics curriculum to be connected early in childhood education institution and home should be developed for parents.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.12
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• pp.3096-3103
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• 2000

High temperature material properties of a welded joint were experimentally studied. Tensile and creep properties were measured for each part of weld metal. HAZ(heat affected zone) and parent metal at 538$^{\circ}C$. HAZ metal was obtained by a simulated heat treatment. Results showed that the order of tensile strength is weld>HAZ> parent both at 24$^{\circ}C$ and at 538$^{\circ}C$. Creep resistance was also the highest for weld metal and lowest for parent metal. Creep rupture life curves were obtained and converted to Monkman-Grant relation which is useful for life assessment. Use of the data obtained in this study is discussed.

• Korean Parent-Child Health Journal
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• v.22 no.1
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• pp.1-9
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• 2019

Purpose: The purpose of this study is to develop educational material for parents of hospitalized preschool children who receive nebulizer therapy treatment. The educational material is aimed at providing information on the correct use of nebulizer. Methods: The development of educational material was based on the ADDIE model and consists of an A4-sized leaflet and a video. Results: The leaflet included basic information, procedures, and cautionary information for nebulizer therapy, as well as frequently asked questions. The one minute and fifty second video is accessed via QR code and provides step-by-step instruction on nebulizer therapy. Conclusion: This study recommends that the educational leaflet and video developed for nebulizer therapy use be provided to parents of preschool children hospitalized in the pediatric ward.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.3
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• pp.54-60
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• 2003

Fatigue strength of offshore structures or ship structures is significantly decreased due to corrosive environment condition such as sea water and/or coal, crude oil of cargoes, compared to that of on shore structures. In corrosive environment, fatigue strength of structures also depends on characteristics of weld material heat affected zone(HAZ). In this research work, rotary bending fatigue tests of parent material and HAZ of TMCP steel were performed in order to investigate the initiation and propagation of cracks both in air and in NaCl solution. Comparison of fatigue strength In relation with the salinity of NaCl were carried out as well. According to the test results weld material or HAZ of TMCP steel showed higher fatigue strength than that of the parent material. The fatigue strength of TMCP steel decreases drastically in NaCl solution compared to that of in air environment. In particular, more reduced fatigue strength is observed in 1% NaCl solution than in 3% NaCl solution.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.27.2-27.2
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• 2010

In recent years, there is a strong requirement of low cost, stable microelectro mechanical systems (MEMS) for resonators, microswitches and sensors. Most of these devices consist of freely suspended microcantilevers, which are usually made by the etching of some sacrificial materials. Herein, we have attempted to use Si nanowires, inherited from the parent Si wafer, as a sacrificial material due to its porosity, low cost and ease of fabrication. Prior to the fabrication of the Si nanowires silver nanoparticles were continuously formed on the surface of Si wafer. Vertically aligned Si nanowires were fabricated from the parent Si wafers by aqueous chemical route at $50^{\circ}C$. Afterwards, the morphological and structural characteristics of the Si nanowires were investigated. The morphology of nanowires was strongly modulated by the resistivity of the parent wafer. The 3-step etching of nanowires in diluted KOH solution was carried out at room temperature in order to control the fast etching. A layer of $Si_3N_4$ (300 nm) was used for the selective fabrication of nanowires. Finally, a freely suspended bridge of zinc oxide (ZnO) was fabricated after the removal of nanowires from the parent wafer. At present, we believe that this technique may provide a platform for the inexpensive fabrication of futuristic MEMS.

• Journal of the Korean Home Economics Association
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• v.48 no.4
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• pp.13-24
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• 2010

The aims of this study were to investigate relation the effects of parent-children relationship on marriage attitude among unmarried persons and to utilize the findings as source material in assessing changes to marriage and family value. In total 654 unmarried persons above the age of 20 in this study. A survey format was used to asked questions, and collected data were subjected to descriptive and comparative analysis using the SPSS(Version 15.0) program. The results were as follows. Among socioeconomic variables, religion was significantly relate to marriage attitude(p < .001). Parent-child relationship and psychological separation was significantly related to marriage value(p < .05). Specifically, high psychological separation from mother, and relationship with father was related to more positive marriage attitudes. Finally, effective socioeconomic variables in marriage attitude were religion, job, psychological separation from mother and father.

• Journal of the Korean Home Economics Association
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• v.47 no.6
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• pp.91-108
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• 2009

The aim of this study was to assist the development of parenting-aid policies by analyzing information from life perspectives, family system theory, and integrated family policy perspectives. For this purpose, we conducted a literature using a variety of sources including internet sites, laws, published material related to current parenting-aid policies. Based on analyses we formulated four agendas: empowering parent competency, supporting diverse family parenting, guaranteeing parent's rights, and supporting parenting of dual-income families parenting. The results were as follow: Firstly, for empowering parent competency, we proposed the development of family relationship empowerment programs including family life cycle and children-raising support services. Secondly, for diverse family parenting, we proposed access to integrated parenting-aid programs dependent on family types. Thirdly, for guaranteeing parent’s rights, we proposed the supporting of child raising costs and tax returns to families with children, and provide child allowances. Finally, for dual-income family parenting, we proposed that schools and communities must recognize that dual-income families are a universal family type, establish family friendly business culture, and to develop a more democratic domestic family-relationship. This policy proposed a new paradigm where parents must be recognized as partners and stakeholder in development of family related policies. Ultimately, such policies will contribute to increased birth rate and development of a more respectful society.

• Journal of the Korean Society of Child Welfare
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• no.55
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• pp.1-29
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• 2016

The purpose of this study was to investigate the influence of household income on children's academic achievement, and to identify the mediating effects of parental time and material investment in the relationship between the two variables. We utilized the third-wave data of the "Seoul Panel Study of Children Surveys(SPSC, 2006)". The major findings of the present study are as follows. First, the results show that household income has a positive influence on children's academic achievement. Second, parental material investment fully mediates the influence of household income on children's academic achievement. Among the variables representing parental material investment, the mediating effects of "purchasing of cognitively stimulating materials" and "participating in extracurricular activities' are found to be statistically significant. However, the two variables representing parental time investment ("parent activities with child out of home" and "parent involvement in school") do not have any significant influence on children's academic achievement. These results indicate that the influence of household income on children's academic achievement can be better explained by parental material investment rather than parental time investment. Implications for policy and practice are discussed.