• Korean Journal of Human Ecology
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• v.22 no.1
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• pp.17-27
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• 2013

The purpose of this study is to investigate children's liquid conservation concept according to their ages and task-situations in the water evaporation phenomenon. Thirty from each 4-, 6- and 8-year-old age groups (total of 90 subjects) were selected for this study. The subjects were recruited from two day-care centers, a kindergarten, and an elementary school, in Seoul. Statistical methods used for data analysis were frequencies, percentiles, means, standard deviations and repeated measures ANOVA. As a result, there was a significant difference in children's liquid conservation concept in the evaporation of water according to their ages and task-situations. 8-year-old children showed levels of cognition than 4- and 6-year-olds. Children showed higher levels of cognition in the task of drying than in the task of water level changes.

• Korean Journal of Child Studies
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• v.25 no.1
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• pp.1-12
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• 2004

This study investigated the relations of children's age, intelligence, and the concept of conservation to their learning of English. Ten 4-year-old children from 1 child-care center and 13 7-year-old children from 1 elementary school were tested after completion of 8 sessions of experimental English classes. Children's intelligence was measured by K-WPPSI for 4-year olds and K-WISC for 7-year-olds. Children were tested for number and liquid conservations. A Korean teacher with 11 years of experience of teaching children at American elementary schools taught the 2 groups with the same subjects and methods. Data were analysed by independent samples t-test, Mann-Whitney U test, and Pearson's r. The results showed that children's age and the concept of conservation were related to English learning. No statistically significant relationship with IQ was found.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.154.1-154.1
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• 2012

조립 완료된 엔진시스템을 발사체 스테이지에 장착하기 위한 제반 사항에 대한 프로세서의 개념을 정리하였다. 엔진을 발사체 스테이지에 장착함에 있어서 주의해야 할 안전규칙, 다음으로 엔진을 이송하고 발사체 스테이지 조립장에서의 포장 해제, 입고 검사, 보존 방법 등 엔진을 스테이지에 장착하기 이전의 준비단계로 엔진 장착 준비 단계, 이후 엔진을 장착하는데 필요한 요구조건과 과정중에 수행되는 시험인 기밀시험, 전기 시험 등에 대한 내용이 포함된 엔진 장착 단계, 또한 엔진을 스테이지로부터 분리해야 할 경우 따라야 할 개괄적인 절차를 포함한 엔진 탈거 및 보관 과정에 대한 내용을 포함한다.

• The Korean Journal of Community Living Science
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• v.23 no.4
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• pp.447-455
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• 2012

The purpose of this study was to investigate children's conception of liquid conservation according to their ages and tasks in the boiling phenomenon The subjects were thirty 4-year-olds, thirty 6-year-olds, and thirty 8-year-olds recruited from two day-care center, one kindergarten, and one elementary school, in Seoul. Statistical methods used for data analysis were frequencies, percentiles, means, standard deviations and repeated measures ANOVA. As the result, there was a significant difference in children's conception of liquid conservation in the boiling of water according to their ages. 8-year-old children showed higher levels of cognition than 4 and 6-year-olds. There was no difference in children's conception of liquid conservation in the boiling of water according to tasks.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.35-38
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• 2007

Aiming at time-dependent performance prediction of Liquid Rocket Engine(LRE) system, Modular Program for Conceptual Design of LRE is reviewed, and a modeling and dynamic analysis of rocket engine system with reference to Rocket Engine Dynamic Simulator(REDS) is outlined. Component modeling is based on classical thermodynamic and inviscid theories, and were formulated mathematically in terms of essential parameters. Essential design parameters are addressed. The rocket engine is modeled as a system of pipes with various hydraulic elements, and then the operate characteristic of that elements are simulated by solving conservation equation sequentially.