• Restorative Dentistry and Endodontics
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• 제48권3호
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• pp.30.1-30.11
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• 2023

Objectives: This study verified the possibility of cementing fiberglass-reinforced posts using a flowable bulk-fill composite (BF), comparing its push-out bond strength and microhardness with these properties of 3 luting materials. Materials and Methods: Sixty endodontically treated bovine roots were used. Posts were cemented using conventional dual-cured cement (CC); self-adhesive cement (SA); dual-cured composite (RC); and BF. Push-out bond strength (n = 10) and microhardness (n = 5) tests were performed after 1 week and 4 months of storage. Two-way repeated measures analysis of variance (ANOVA), 1-way ANOVA, t-test, and Tukey post-hoc tests were applied for the push-out bond strength and microhardness results; and Pearson correlation test was applied to verify the correlation between push-out bond strength and microhardness results (α = 0.05). Results: BF presented higher push-out bond strength than CC and SA in the cervical third before aging (p < 0.01). No differences were found between push-out bond strength before and after aging for all the luting materials (p = 0.84). Regarding hardness, only SA presented higher values measured before than after aging (p < 0.01). RC and BF did not present 80% of the maximum hardness at the apical regions. A strong positive correlation was found between the luting materials' push-out bond strength and microhardness (p < 0.01, R² = 0.7912). Conclusions: The BF presented comparable or higher push-out bond strength and microhardness than the luting materials, which indicates that it could be used for cementing resin posts in situations where adequate light curing is possible.

• 한국식생활문화학회지
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• 제19권3호
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• pp.336-347
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• 2004

This study was conducted to investigate eating-out behavior patterns of youths, especially junior high and senior high school students. 1600 questionnaire surveys were distributed and 1487 were used for analysis. In order to consider regional differences as well as overall characteristics of youths' eating-out behaviors, the subjects were evenly sampled from north Seoul, south Seoul, big cities, middle/small cities and small towns. As for the frequency of eating-out, 62.7% of respondents answered once to twice per week. For the can of more than 5 times of eating-out per week, the respondents from south Seoul showed the highest frequency. For the case of no eating-out, the highest frequency was shown from the small towns. As for the most frequently visited place for eating-out, 33.6% of respondents answered Korean style restaurants, and 17.6% Boon-sik(Sanck-bar). Regarding the preference of Korean style restaurants, the highest rate was shown from the residents of big cities. For the question of when they eat out, 89.6% answered dinner and 6.3% lunch. For the question about reason of choosing particular restaurants, 61.5% of respondents referred to tastes and 16.6% price. For the question of the most important reason of eating out, 52.6% point out 'meal solution' and 25.6% 'for meeting.' As for the people accompanied when eating out, 67.2% of the respondents answered family. For the cost of eating out per person, 45.7% of the respondents spent 2000-4000 won for lunch; 31.1% spent 5000-10,000 won for dinner; 33.7% of the respondents spent more than 20,000 won for the special events. Regarding the regional differences of eating-out cost, respondents from south Seoul tended to spend the biggest amount of money for lunch, dinner and special day.

• 한국학교수학회논문집
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• 제17권2호
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• pp.291-319
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• 2014

이 연구의 목적은 제곱근과 실수 단원에 대한 Worded-Out Examples을 활용하여 중학생들의 수학적 사고과정을 수학적 숙련도(mathematical proficiency)를 통해 규명하는 것이다. WOE는 "학생의 학습을 위하여 전문가의 풀이 과정을 상세히 제공하는 도구"로 학생들의 수학에 대한 과정과 구조의 학습을 돕기 위한 것이다. 이를 위해, WOE 문항을 개발하여 6명의 중학생들이 활용하도록 하고 2명의 학생을 대상으로 인터뷰를 실시하였다. 수집된 자료를 분석하였고 그 결과는 다음과 같다. 학생들의 사고과정은 이해한 내용을 활용하여 적절한 단계로 문제를 풀어가는 '이해 계산', '계산 추론', '이해 계산 추론'으로 나타났다. 또한 학생들 대부분이 '적용'하는 것에는 어려움을 겪는 것으로 나타났다.

• 한국심리학회지 : 문화 및 사회문제
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• 제14권1호_spc
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• pp.299-317
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• 2008

2000년대를 전후로 급증한 청소년들의 학업중단을 실태와 기존의 연구들을 통해 종합적으로 조망하였다. 용어, 실태, 원인과 과정 및 학업중단 이후 과정으로 나누어 우리나라 청소년의 학업중단을 이해하고, 이를 다시 12가지 특성으로 정리하였다. 그리고 이러한 특성들을 생태학적 모형으로 재구조화하였다. 1990년대 중반에 시작된 사회적 안정구조의 흔들림과 1998년의 IMF 사태는 청소년들의 1차 환경인 가정과 학교에 영향을 미쳤다. 가정은 이혼 등의 갈등이 표면화되면서 청소년에 대한 심리적 지지와 경제적 지원을 약화시켰고, 학교에서는 교권과 교칙이 약화되면서 교사와의 갈등, 학업의 목적과 흥미 상실로 나타났다. 청소년들은 우울, 무력감, 공격성과 같은 정서적 반응, 미래의 불투명성, 학업적 의미 상실과 같은 인지적 반응 및 부적절한 성행동, 폭력과 같은 표면화된 비행행동반응을 보였다. 이러한 심리적 상태는 가출과 학업중단이라는 표면화된 행동으로 드러나게 되었고, 이후 이들의 학업 유지 의도에도 불구하고 준비되어 있지 않은 사회에 의해 비행화가 가속되었다. 이들에 대한 국가적 대처에 대한 제안과 제한점들이 논의에 첨가되었다.

• 한국식품영양학회지
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• 제14권1호
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• pp.69-76
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• 2001

This study was conducted to find out the actual condition of dining-out and the propensity to dinning-out at luncheon time according to gender, occupation and age in Busan area. The survey was conducted on 564 peoples who live or work, including students acted more than 4th grade in elementary school in Busan area. The results of the questionaires are as follows ; The place to eating-out at luncheon time in order of "about the office or the school" and "about the house". Restaurants used frequently were in order of "Flour food shop", "Korean-style food shop" and " "Chinese-style food shop". Partner to eating-out were in order of "friend", "fellow worker" and "family" But. the results of the place to eating-out, restaurants used frequently and partner to eating-out at luncheon time were different according to sex, occupation and age groups.

• 산업경영시스템학회지
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• 제18권36호
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• pp.349-363
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• 1995

The purpose of the study was to estimate and analyze the rates of return to educational investment. The study was designed to estimate the social and private rates of return to educational investment by school level and sex in order to measure education's economic value with a viewpoint of human capital theory. The produced result of this study are as follows. The social rates of return to education turned out to be male high school 7.94%, male junior college 3.74%, male university 8.50% female high school 4.30%, female junior college 10.11%, female university 6.92%. The private rates of return to education turned out to be male high school 8.41%, male junior college 3.39%, male university 8.38%, female high school 7.90%, female junior college 10.34%, female university 7.33%, In order to measure economic value of educational investment, rates of return to education were compared with those to physical capital investment. Social rates of return to education turned out to be profitable for female junior college, while for private rates of return to education turned out to be profitable in all school levels except for male junior college.

• 한국학교ㆍ지역보건교육학회지
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• 제12권2호
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• pp.97-112
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• 2011

Objectives: The purpose of this study is to identify upper primary school children's knowledge and attitude about cancer, empathy, and attitudes about child with cancer, and to examine the relations between these variables and factors that influence. Methods: Methods: The participants included 474 fifth and sixth grade students. Data were analyzed using Pearson correlation coefficients, ANOVA and Tukey test with SPSS/WIN 18.0. Results: Mean scores were for knowledge about cancer 6.03 out of a possible 1, attitude about cancer 2.23 out of a possible 5, attitudes about child with cancer 1.11 out of a possible 3, and empathy 3.18 out of a possible 5. There were significant differences in knowledge about cancer according to school grades and parents' interest in health management. Attitude about cancer showed significant differences according to harmony of family life, worries about cancer, school life, academic achievement, school parents' interest in health management and cancer education. Empathy showed significant differences according to school grades, gender, school life, harmony of family life, and parents' interest in health management. Attitudes about child with cancer showed significant differences according to school grades, school life, and parents' interest in health management. Knowledge about cancer and empathy showed a positive correlation with attitudes about child with cancer. Knowledge and attitude about cancer, and empathy showed a significant influence on attitudes about child with cancer. Conclusion: Results of this study indicate that development of an appropriate knowledge and attitudes about cancer, and empathy by late school-aged children should lead to the positive attitudes about child with cancer.

• 대한화학회지
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• 제56권3호
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• pp.378-385
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• 2012

이 연구에서는 학생들의 학교 밖 과학 경험과 과학의 본성에 대한 견해 사이의 관계를 조사하였다. 연구 대상은 서울시 소재의 학교에서 표집한 6학년 267명, 8학년 281명, 10학년 307명이었다. 과학의 본성에 대한 학생들의 견해 조사에는 과학의 목적, 과학 이론의 정의, 과학적 모형의 성질, 과학 이론의 잠정성, 과학 이론의 기원에 관한 5 문항으로 이루어진 과학의 본성 검사지를 이용하였다. 학생들의 학교 밖 과학 경험은 7 문항으로 구성된 수정본 과학 경험 검사의 하위 범주를 이용하여 측정하였다. 연구 결과, 6학년에서는 학생들의 학교 밖 과학 경험과 과학의 본성에 대한 견해 사이에 통계적으로 유의미한 관계가 나타나지 않았다. 8학년의 경우, 학교 밖 과학 경험 상위 수준 학생들은 과학적 모형의 성질에 대한 문항에서 현대 인식론적인 견해를 지니고 있었으나, 과학 이론의 잠정성 문항에서는 반증주의적 견해를 지니고 있었다. 10학년 학생들의 경우, 과학의 목적, 과학 이론의 정의, 과학적 모형의 성질에 대한 문항에서 학교 밖 과학 경험 상위 수준 학생들이 하위 수준 학생들에 비해 인식론적으로 세련된 견해를 지니고 있는 것으로 나타났다.

• Journal of Mechanical Science and Technology
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• 제15권7호
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• pp.823-830
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• 2001

The single fiber pull-out technique has been commonly used to characterize the mechanical behavior of fiber/matrix interface in fiber reinforced composite materials. In this study, an improved analysis considering the effect of thermal residual stresses in both radial and axial directions is developed for the single fiber pull-out test. It is found to have the pronounced effects on the stress transfer properties across the interface and the interfacial debonding behavior.

• Restorative Dentistry and Endodontics
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• 제44권4호
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• pp.37.1-37.10
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• 2019

Objectives: This study evaluated the bond strength of various fiberglass post cementation techniques using different resin-based composites. Materials and Methods: The roots from a total of 100 bovine incisors were randomly assigned to 5 treatment groups: G1, post + Scotchbond Multi-Purpose (SBMP) + RelyX ARC luting agent; G2, relined post (Filtek Z250) + SBMP + RelyX ARC; G3, individualized post (Filtek Z250) + SBMP; G4, individualized post (Filtek Bulk-Fill) + SBMP; G5, individualized post (Filtek Bulk-Fill Flow) + SBMP. The samples were subjected to the push-out (n = 10) and pull-out (n = 10) bond strength tests. Data from the push-out bond strength test were analyzed using 2-way analysis of variance (ANOVA) with the Bonferroni post hoc test, and data from the pull-out bond strength test were analyzed using 1-way ANOVA. Results: The data for push-out bond strength presented higher values for G2 and G5, mainly in the cervical and middle thirds, and the data from the apical third showed a lower mean push-out bond strength in all groups. No significant difference was noted for pull-out bond strength among all groups. The most frequent failure modes observed were adhesive failure between dentine and resin and mixed failure. Conclusions: Fiberglass post cementation using restorative and flowable bulk-fill composites with the individualization technique may be a promising alternative to existing methods of post cementation.