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트리페닐 파라니트로벤젠술포네이트와 아닐린간의 친핵성 치환반응
고한중,신철호 全州敎育大學校 科學敎育硏究所 1997 科學 敎育 硏究 論文集 Vol.19 No.1
Kinetic studies on the nucleophilic substitution reaction of triphenyl P- nitrobenzenesulfonate ((C_6H_5)_3COSO_2C_6H_4-p-NO_2) with X-substituted anilines in methanol have been carried out in order to elucidate the reaction mechanism. (i) The triphenyl p-nitrobenzenesulfonate had markedly smaller magnitudes of ρ_x( or β_x) values compared with those for other reactions( example : benzhydryl system), and (ii) the small inverse kinetic isotope effects(k_H/k_P <1.0) involving deuterated aniline nucleophiles, it was conclude that the reaction proceed by dissociative S_N2 mechanism. There are, however, two paths in the transition state(TS), the uncatalyzed and base-catalyzed.
초등학교 과학수업에서 실패에 대한 인내 수준에 따른 순환학습 수업의 효과
고한중,구이주,강석진 한국과학교육학회 2005 한국과학교육학회지 Vol.25 No.2
이 연구에서는 순환학습 수업이 초등학교 5학년 학생들의 학업 성취도와 과학 학습 환경에 대한 인식에 미치는 영향을 조사했다. 또한, 학생들의 실패에 대한 인내 수준을 측정하여 실패에 대한 인내 수준과 순환학습 수업 처치 사이의 적성-처치 상호작용 효과를 조사했다. 1개 초등학교의 2개 학급 56명을 학급 단위로 통제 집단과 처치 집단으로 할당했다. 사전 검사로 실패에 대한 인내 검사와 과학 학습 환경에 대한 인식 검사를 실시했다 '용액의 성질과 '용액의 반응' 단원에 대해 11차시에 걸쳐 처치를 실시했다. 사후 검사로 학업 성취도 검사와 과학 학습 환경에 대한 인식 검사를 실시했고, 3개월 후에 학업 성취도 파지 검사를 실시했다. 이원 공변량 분석 결과, 학업 성취도 전체 점수에서 약하게 유의미한 주효과가 나타났고, 적용 영역에서는 통계적으로 유의미한 주효과가 나타났다. 그러나 학업 성취도 파지 검사에서는 전체 점수와 적용 영역의 점수 모두에서 유의미한 주효과가 발견되었다. 과학 학습 환경에 대한 인식 검사의 참여성과 친화성 영역에서는 통계적으로 유의미한 상호작용 효과가 있었다. In this study, we investigated the effects of the learning cycle instruction on 5th graders' achievement and their perceptions toward science learning environment. We also measured the degrees of students' failure tolerance and examined the aptitude-treatment interaction between students' failure tolerance and the learning cycle instruction. Two classes (56 students) from an elementary school were respectively assigned to a control group and a treatment group. A school failure tolerance test and a test of perceptions toward science learning environment were administered as pretests. Students were taught about "properties of solution" and "reactions of solution" for 11 class periods. A researcher-made achievement test and the test of perceptions toward science learning environment were administered as posttests. An achievement retention test were also administered after 3 months. Two-way ANCOVA results indicated that a slightly significant main effect was found in the total scores of the achievement test and a statistically significant main effect was found in the scores of application subcategory of the achievement test. However, statistically significant main effects were found in both the total and the application subcategory scores of the achievement retention test. In the involvement and affiliation subcategories of the test of perceptions toward science learning environment, there were statistically significant interaction effects. Educational implications are discussed.
고한중,강석진 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.5
The solvolysis rate constants of 2,2,2-trichloroethyl chloroformate (Cl3CCH2OCOCl, 3) in 30 different solvents are well correlated with the extended Grunwald-Winstein equation, using the NT solvent nucleophilicity scale and the YCl solvent ionizing scale, with sensitivity values of 1.28 ± 0.06 and 0.46 ± 0.03 for l and m, respectively. The activation enthalpies (ΔH≠) are 10.1 to 12.8 kcal·mol−1 and the activation entropies (ΔS≠) are −27.8 to −36.8 cal·mol−1·K−1, which is consistent with the proposed bimolecular reaction mechanism. The kinetic solvent isotope effect (kMeOH/kMeOD) of 2.39 is also in accord with SN2 mechanism probably assisted by general-base catalysis.
고한중,고은정 全州敎育大學校 科學敎育硏究所 1999 科學 敎育 硏究 論文集 Vol.21 No.-
The purpose of this study was to investigate of perceptions of prospective elementary school teachers about concentration of solution. For this study, 139 prospective elementary school teachers were selected from Chonju National University of Education. For the most part of prospective elementary school teachers well understand the meaning of concentration of solution, however somewhat they were not clear conception for difffrence between a mixture and a chemical compound.
고한중,강석진,김철주 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.2
Rates of solvolyses of benzhydryl chloride (Ph2CHCl, 1) and benzhydryl bromide (Ph2CHBr, 2) in ethanol, methanol, and aqueous binary mixtures incorporating ethanol, methanol, 2,2,2-trifluoroethanol (TFE) and acetone are reported. Solvolyses were also carried out in TFE-ethanol mixtures. Application of the extended Grunwald- Winstein equation led to l value of 1.19 (1), 1.29 (2) and m value of 1.00 (1), 0.77 (2), correlation coefficient of 0.965 (1) and 0.970 (2). Sensitivities (l = 1.19 (1), 1.29 (2) and m = 1.00 (1), 0.77 (2)) were similar to those obtained for several previously studied solvolyses, in which an SN2 pathway is proposed for the solvolyses of benzhydryl halides (Ph2CHX, X = Cl or Br).