• 한국생활과학회지
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• 제22권1호
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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.

• 아동학회지
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• 제25권1호
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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.

• 천문학회보
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• 제37권2호
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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.

• 한국지역사회생활과학회지
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• 제23권4호
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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.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.35-38
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• 2007

액체로켓엔진(Liquid Rocket Engine) 의 천이성능 예측을 위해 선행연구 되었던 LRE 시스템 모듈화 프로그램의 결과를 살펴보고, 일본의 로켓엔진 동적 해석 프로그램(Rocket Engine Dynamic Simulator)의 엔진 시스템 동적 해석 방법과 모델링에 대해 고찰하였다. LRE 시스템 모듈화 프로그램에서는 각 구성품에 대한 설계 인자를 수학적으로 모델링하였고 구성품 간의 유량과 압력을 매칭시켜 통합하여, 로켓엔진 시스템의 요구조건을 만족하는 각 구성품에 대한 주요 설계 파라미터를 도출하는 과정에 관하여 논의하였다. 로켓엔진 시스템을 유한한 배관요소들의 연결로 모델링하고, 시간의 함수로 표현되는 보존방정식을 적용하여 터보펌프, 밸브, 오리피스，추력실 등 유체기기의 작동 특성을 모사하는 동특성 설계 과정에 관하여 고찰한다.