• Korean Journal of Soil Science and Fertilizer
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• v.47 no.3
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• pp.179-186
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• 2014

Weathering indexes of the typical pedons derived from different parent materials of the soils of Korea were calculated by Kronberg and Nesbitt (1981) to understand weathering degree of the soils which might give a clue of soil formation and characterizing a soil pedon. The weathering index W1 was chemical change index, and the weathering index W2 was silicate dominant index. The chemical compositions of the 49 typic pedons were extracted from the Taxonomical Classification of Korean Soils (NIAST, 1999). The weathering indexes of Kimhae series, derived from fluvio marine material, were the highest among the analyzed soils. Within parent materials, the weathering indexes of the soils derived from limestones parent materials were high, and those derived from phorphyry materials were low. The relationship between W1 and W2 showed unique pattern which implied certain sequence within the same parent materials.

• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.705-710
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• 2002

Welding is used not only during the shipbuilding, but also during the repairing of ships. While repairing of ships, it is inevitable to weld new materials with degraded materials. In this case, it is predicted that the strength of both the sections is not identical each other. In this study, the respective welded joints in terms of mechanical properties such as microstructure, mechanical strength and fatigue crack propagation, with the component obtained from the barge used for a long-term period, were analyzed. It was found that the material degradation had a significant effect on the welded joints. The fatigue crack propagation in welded sections showed a big difference. The rate of fatigue crack growth of degraded material for both heat affected zone and parent metal was faster than that of new material. By contrast, The result within identical materials showed that the heat-affected zone was slower than that of parent metal

• Journal of the Korean Society for Precision Engineering
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• v.19 no.11
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• pp.75-82
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• 2002

Welding is used not only for the shipbuilding, but also for the repairing of ships. While repairing of ships, it is inevitable to weld new materials with degraded materials. In this case, it is predicted that the strength of both the sections is not identical each other. In this study, the respective welded joints in terms of mechanical properties such as microstructure, mechanical strength and fatigue crack propagation, with the component obtained from the barge used for a long-term period, were analyzed. It was found that the material degradation had a significant effect on the welded joints. The fatigue crack propagation in welded sections showed a big difference. The rate of fatigue crack growth of degraded material for both heat affected zone and parent metal was faster than that of new material. By contrast, the result from identical materials showed that the rate of fatigue crack growth of the heat-affected zone was slower than that of parent metal.

• 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.

• 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 the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.91-97
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• 2010

Micro-abrasive Jet Machining is one of the new technology which enables micro-scale machining on the surface of high brittle materials. In this technology it is very important to fabricate a mask that prevents excessive abrasives not to machine un-intend surface. Our previous work introduced the micro-stereolithography technology for the mask fabrication. And is good to not only planar material but also for non-planar materials. But the technology requires a 3 dimensional mask CAD model which is perfectly matched with the surface topology of parent material as an input. Therefore there is strong need to develop an automated modeling technology which produce adequate 3D mask CAD model in fast and simple way. This paper introduces a fast and simple mask modeling algorithm which represents geometry of models in voxel. Input of the modeling system is 2D pattern image, 3D CAD model of parent material and machining parameters for Micro-abrasive Jet Machining. And the output is CAD model of 3D mask which reflects machining parameters and geometry of the parent material. Finally the suggested algorithm is implemented as software and verified by some test cases.

• Journal of Korean Neurosurgical Society
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• v.29 no.12
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• pp.1592-1599
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• 2000

Objective : Multiple cerebral aneurysms reportedly account for 14-33% of all cerebral aneurysms. However, multiple separate aneurysms on single parent artery are uncommon. The majority of these are found on middle cerebral artery(MCA). Multiple aneurysms arising from anterior communicating artery(ACoA) are rare. We report 5 cases of multiple aneurysms developed separately on single artery and describe angiographic and operative findings of these lesions. Materials and Methods : Among 127 patients of cerebral aneurysms operated in our hospital, only 5 had multiple aneurysms on single parent artery. Results : Among 5 cases, 4 were diagnosed preoperatively and the only one was found intraoperatively. Two were found on MCA bifurcation, one on M2 and two on ACoA. All separate aneurysms developed on single parent artery were treated successfully with multiple clipping. Conclusion : Multiple cerebral aneurysms, developed separately on single parent artery, are uncommon. Furthermore, those arising from ACoA are very rare. Despite the advanced technology in radiological examinations, multiple cerebral aneurysms may not be detected on preoperative study only. Close proximity or smaller size of the lesion may be responsible for the preoperative false negative angiographic findings.

• The Journal of Economics, Marketing and Management
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• v.4 no.4
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• pp.29-35
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• 2016

This study has focused on the transfer of infants and Toddlers-protecting responsibilities from families to infants and Toddlers education agencies due to an increase of a double-income family and nuclear family. It is because there is insufficient safe play space from the moment when infants and Toddlers return from infants and Toddlers education agencies to home due to a high crowding of housing and increase of vehicle, and there can be difficulties to take responsibilities of infants and Toddlers safety with a mere recognition and effort of parent. Thus, to suggest a safety education through mutual contact between the communities and agencies supporting parent role in a level of social welfare, its potential has been identified through a frequency analysis on 60 participants of experimental group who have trained a safety education and 60 participants of control group who have not trained a safety education. As a result of frequency analysis, the increase in safety condition in Korea, safety and development of infants and Toddlers, safety of play materials, and safety knowledge on general part of facility safety has detected and the practice of safety and safety consciousness has also identified to be more effective. The results of this study has shown a potential to verify its efficacy if it is verified through an elaborative model of safety education based on parents of young infants and Toddlers family.

• Journal of the Korean Home Economics Association
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• v.34 no.3
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• pp.291-303
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• 1996

Generally fairytales are recognized as very effective educational materials. However, some of them includes negative prejudices on stepparents, especially stepmother. These contents are very harmful to development and adjustment of children in remarried families. Moreover, not so many studies have been done that even the results were insufficient to not only practical but also academical needs. Therefore this study purposed to investigate the parent -and stepparent- figures perceived by children with the knowledge about the related fairytales. Specific research problems are as follows; 1. How many children do know the contents of the 4 related fairytales such as Snow Whit, Sindellera, Kongjui Patjui and Changwha Honglyun? 2. What are the parent -figures perceived by the children with the knowledge about the 4 traditional fairytales? 3. What are the stepparent- figures of the subjects? 4. Is the children's sex the statistically significant variable in their parent -and stepparent- figures? 5. Is the children's age the statistically significant variable in their parent -and stepparent- figures? 6. Is the their parents' educational level the statistically significant variable in their parent -and stepparent- figures? 175 boys and girls of age -9 and- 11 were selected from 2 primary schools in Seoul. All of them were from normal families. As the steadyselling books, 18 fairytales were chosen by 7 booksellers of large scale bookstores in Seoul. And then by 10 teachers and 10 literay persons, 4 Korean and foreign traditional fairytales were seleced at last. The questionaire of 5 subareas was developed and used as the research tools, in which include 40 items. SPSS/pc program were used for data analysis for frequency, percentile, mean, and t-test. The followings are the findings with cronbach α=.80 and .94 parent -and stepparent- figures respectively. 1)The contents of the 4 tradional fairytales were read already or wellknown, even if the children who didn't. 2)The subjects showed very positive their own parent-figures such as sweet, lovely, reliable, and true or good person. 3)The subjects showed very negative stepparent-figures in contrast. 4)They showed significant sex difference(p<0.5) in their own parent-figures. And girls were more positive than boys who were a little more positive(on insignifficant level) than girls in stepmother-figures. 5)All the subjects had positive parent-figures and negative stepparent-figures. 6)Their parents education level was no significant variable in the prediction of their parent -and stepparent- figures.