Part I: The effects of laboratory curriculum and instruction on undergraduate students' understanding of chemistry. Part II: Raman spectroscopy studies of the synthesis of cuprates in molten hydroxide fluxes

Rickey, Dawn Kerry University of California, Berkeley 1999 해외박사(DDOD)

<italic>Part I</italic>: <italic>The Effects of Laboratory Curriculum and Instruction on Undergraduate Students' Understanding of Chemistry</italic>. Shallow learning, that is, acquiring factual and procedural knowledge without a deeper understanding of the underlying ideas, is a typical result of science courses taught via the standard modes of lecture and follow-the-recipe laboratory experiments. To address the problem of shallow learning in general chemistry, my colleagues and I developed, implemented, and assessed a new laboratory program. The design of the curriculum and instruction for the MORE laboratory course was based on research in cognitive science and education. We also developed a new instructional tool, the Model-Observe-Reflect-Explain (MORE) Thinking Frame, to support our curricular and instructional goals. The MORE laboratory curriculum and instruction was tested in two laboratory sections selected at random from the general chemistry course, and was assessed in comparison with two matched Control sections participating in the standard laboratory curriculum. Analysis of the data revealed a consistent picture of students enrolled in the MORE laboratory course developing significantly enhanced metacognitive abilities, understanding of the fundamental chemistry ideas studied in the general chemistry course, and abilities to solve near transfer and isomorphic examination problems compared with the Control group. The design of the Model-Observe-Reflect-Explain (MORE) laboratory instruction around our three principles encouraged and supported students' development of skills for reflection upon and revision of their understanding of the basic chemistry ideas studied in the laboratory, resulting in improved learning and problem-solving. <italic>Part II</italic>. <italic>Raman spectroscopy studies of the synthesis of cuprates in Molten Hydroxide Fluxes</italic>. The goal of the research presented here was to refine the model of cuprate synthesis in alkali metal hydroxide melts by using Raman spectroscopy to directly determine the oxo and metal-oxo solution species present in hydroxide melts under particular reaction conditions. The Raman spectroscopy studies described in this thesis were successful at contributing to an improved understanding of the behavior of copper in molten hydroxide solutions. In addition, the Raman spectra provide the first direct evidence of the existence of a stable Cu<super>3+</super> species in molten hydroxides solutions open to the air at temperatures above about 400°C. One key finding of the Raman spectroscopy studies was that, contrary to what was previously postulated, Cu<super>3+</super> was found to be more stable in dry, highly oxidizing melt conditions at high temperatures than it is in melts of intermediate dryness and temperature. (Abstract shortened by UMI.).

Learning the language of organic chemistry: How do students develop reaction mechanism problem-solving skills?

Anderson, Jason P Purdue University 2009 해외박사(DDOD)

Reaction mechanisms and the associated electron-pushing formalism are a symbolic language used by practicing organic chemists to navigate problems common to organic chemistry. Although the importance of this mechanistic language has been noted by practitioners and educators alike, it is often misunderstood and poorly applied by students and novice organic chemists. It was the disconnection between student and practitioner that was at the center of this research. The goal of this study was to determine how organic chemistry graduate students' mechanistic problem-solving strategies developed as they became members of the organic chemistry research community. This process was explored in eleven organic chemistry graduate students by investigating the participants' interaction with: their dissertation research projects, weekly mechanism meetings held by organic chemistry research groups, and a variety of activities that were dependent on their year in graduate school. These activities included: advanced organic chemistry coursework and projects, original proposals (OP), the senior research seminar, and the process by which they defend their dissertation and search for a job. This study was designed and analyzed using a constructivist framework that was supplemented with situated learning perspectives (i.e. communities of practice). The data collected -- interviews, observations, artifacts, and field notes -- were then analyzed through an ethnomethodological lens. The results of this study indicated that the participants' overall developmental changes occurred as a result of acculturation in the organic chemistry community of practice. Furthermore, it was the authentic and active problem-solving efforts in the activities inherent to this community that provided the participants with a sense of ownership and membership within this community of practice through legitimate participation in these activities. It was apparent that the participants' interactions with this community -- through the research literature, their group members, research advisors, and course instructors -- were also essential to their development in general. This interaction and the participants' research problem-solving efforts resulted in a significant developmental shift in the usefulness of mechanisms. Finally, a theme that unified all of the participants in this study was their use of mechanisms to troubleshoot unexpected problems both in coursework and research.

Gas-phase covalent and non-covalent ion/ion chemistry of biological macromolecules

Stutzman, John R Purdue University 2013 해외박사(DDOD)

Gas-phase ion/ion chemistry involves the interaction of oppositely charged ions inside of the mass spectrometer. During this gas-phase chemistry, particle transfer (i.e., proton and electron) or synthesis can occur at rapid reaction rates. Particle transfer represents a mature area of ion/ion chemistry, while selective covalent modification represents a fairly new area of gas-phase chemistry. Gas-phase covalent chemistry is based on traditional solution phase organic chemistry. The work demonstrated in this dissertation greatly involves gas-phase covalent and non-covalent Schiff base chemistry on peptide and protein ions. The reagent dianion, 4-formyl 1,3-benzene disulfonic acid, has been used to covalently modify unprotonated primary amines present in peptide and protein ions. In addition, strong non-covalent interactions have also been observed with arginine-containing peptides ions. Studies of their dissociation behavior as well as the nature of their interaction (i.e., covalent versus non-covalent) have been investigated. Application of this Schiff base ion/ion chemistry has been demonstrated on matrix assisted laser desorption/ionization (MALDI)-derived peptide ions. Such Schiff base ion/ion chemistry, whether electrospray or MALDI-derived, can produce complementary or even an increase in structural information. Multiple covalent modifications within one ion/ion encounter have been demonstrated on peptide and protein cations via Schiff base cluster anions. This dissertation also highlights the gas-phase transformation of phosphatidylcholine cations into demethylated phosphatidylcholine anions, which provides an increase in structural information upon activation. As a whole, gas-phase covalent and non-covalent ion/ion chemistry represents a promising new area for identifying and characterizing biological analytes.

New fields in organic chemistry: Developments in aqueous organoindium chemistry and ring closing olefin metathesis

Mendez-Andino, Jose Luis The Ohio State University 2001 해외박사(DDOD)

Organoindium chemistry is an area that has elicited considerable interest recently because it has been found that selected processes can be performed in aqueous media efficiently. These findings have caused a major impact in the quest for alternative synthetic pathways for pollution prevention. Similarly, the discovery of new reagents to perform ring closing metathesis reactions has received enormous attention in recent years. Grubbs' catalyst is the reagent that has revolutionized this area and provided the organic chemist with a powerful new synthetic tool. Novel methodologies in the areas of organoindium chemistry and ring closing olefin metathesis have been responsible for significant advances in synthetic chemistry in recent years. Our goal was therefore to merge the fields of aqueous organoindium chemistry and ring-closing olefin metathesis (RCM) to develop methodologies with application in synthetic organic chemistry. Initially, we examined the stereochemical course of the intramolecular cyclization of allylic bromides with indium metal in water. Proper comparison with the fluoride ion-promoted ring closure of allylsilanes in organic media was made. The second stage of this work consisted in developing a general procedure for the synthesis of α-methylene lactones fused to larger rings. The convenient approach originates with two ω-unsaturated aldehydes of the same or different chain length. Organoindium chemistry and ring closing olefin metathesis were employed to develop the convergent strategy for the synthesis of α-methylene-γ-lactones fused to medium and large carbocyclic ring systems. We also targeted for investigation a convenient method for achieving four-carbon intercalations between the carbonyl groups of α-diketones. A three-step sequence consisting of indium-promoted diallylation, ring-closing metathesis, and oxidative diol cleavage with lead tetraacetate lends itself conveniently to useful structural modifications. Finally, we investigated the synthesis of an homologous series of bicyclo[1.1.1]pentane-1,3-dicarboxylate esters featuring ω-alkenols of differing chain length. Their ability to undergo ring closing metathesis/paddlane formation in the presence of Grubbs' catalyst was studied in detail.

Study of reductions using flow chemistry and catalytic hydroboration of alkenes and alkynes with potassium carbonate(cat.)

Kim Taesung 강원대학교 대학원 2019 국내석사

<Part I> Due to its high contact efficiency and heat capacity, the flow reactions under micro reactor is known to be highly efficient and reactive than conventional batch systems. Using flow system, with low catalyst load and shorter reaction time an organic reaction can operate with excellent yield. As a result numerous chemical transformations which otherwise difficult to produce in conventional methods were reported by various academies and institutes. As part of our search for efficient reducing agents and selective reductions, and in view of flow technique importance, we made efforts for partial reductions and hydroboration reactions under flow chemistry with ester group. Accordingly, an ester group was reduced with LiOtBu, DIBALH (through the in-situ generated LDBBA), and LiOtBu, MeLi catalyzed hydroboration with pinacolborane. <Part II> The importance of green protocols under the environmental concern, cost reduction and simplify of procedures has dawn great attention in recent years. In addition, increased efficacy of the reaction also expected due to the intimacy of the reagents and catalysts used. In this regard, catalytic reactions under minimal solvent or solvent free conditions are becoming most valuable choices in research. The hydroboration of unsaturated hydrocarbons provides useful synthons for cross-coupling and other important functional transformations. The hydroboration of unsaturated bonds with sodium borohydride-aluminum chloride was first reported by Nobel laureate Prof. H. C. Brown. Later, efforts have been made by several authors to find efficient catalytic system for unsaturated hydroboration (C-C and C=X; X = O, NH). As a result number of catalytic systems including transition metal complexes, main group-alkaline earth metals, and lanthanide complexes were reported. In the present study, we have taken up the research on transition metal free hydroboration of alkenes and alkynes using lower active reductant such as pinacolborane (HBpin) catalyzed by inexpensive and mild base K2CO3. Accordingly a 1-5 mol% K2CO3 could efficiently provided hydroboration in good yields under solvent free condition. Flow chemistry란 반응물을 반응기 내부로 주입시켜 연속적인 흐름을 통해 반응하는 방식이다. 반응기로는 micro reactors가 이용되기도 하는데 부피 대비 표면적이 높은 장점이 있어 열전달 효율 등이 높다. 이러한 장점을 토대로 DIBALH와 lithium tert-butoxide를 이용한 esters의 부분환원 및 methyl lithium 또는 lithium tert-butoxide를 촉매로 이용한 esters의 촉매 수소화 붕소 첨가반응을 flow chemistry에 적용하여 본 결과 batch system 보다 LDBBA의 합성에 효과적임을 알 수 있었다. 그러나 esters의 부분환원 및 촉매 수소화 붕소 첨가반응에서는 기존의 batch system과 비교하여 뚜렷한 장점을 찾을 수 없었다. 수소화 붕소 첨가반응은 유기합성에 중요한 반응으로 최근에는 다양한 촉매를 이용한 촉매 수소화 붕소 첨가반응이 연구되고 있다. 현재까지 불포화 탄화수소의 촉매 수소화 붕소 첨가 반응에 보고된 촉매들은 대부분 비교적 고가의 전이금속을 포함하거나 보관 및 사용이 어려운 강한 친핵성 및 염기성의 시약이 대부분이다. 이와 같은 문제점을 해결하고 보다 효과적인 불포화 탄화수소의 촉매 수소화 붕소 첨가반응을 진행하기 위해 새로운 촉매로 potassium carbonate를 적용시켜 본 결과 알켄으로부터 상응하는 alkyl boronic esters를 알카인의 경우에도 상응하는 vinyl boronic esters를 성공적으로 합성 할 수 있었다.

Synthesis and Evaluation of Novel Radiotracers using Click Chemistry : Click chemistry를 이용한 새로운 방사성추적자의 합성 및 평가

김동현 성균관대학교 일반대학원 2009 국내박사

It is important to develop novel compounds possessing potent biological activities for medical uses. However, synthesis of these compounds is generally slow, costly, and hindered by complex synthesis pathways. In this context, synthesis of novel radiopharmaceuticals is also a difficult task. Click chemistry known as Cu(I)-catalyzed 1,3-cycloaddition between terminal alkynes and azides has been shown to be a simple, regioselective and high yielding reaction for synthesis of various triazole compounds. In this study, therefore, we developed 4-[18F]fluoro-1-butyne, a synthon for click chemistry with azides, and applied it to development of novel positron emission tomography (PET) radiotracers, such as glucose, fatty acid, and cRGD peptide analogs. Radiolabeled glucose analogs are attractive probes for metabolic imaging. However, there are no suitable glucose radiotracers, except [18F]FDG. In this study, a 18F-labeled glucose analog, 4-[(2-[18F]fluoroethyl)-1-(β-D-glucopyranosyl)]-1H-1,2,3-triazole ([18F]1), was synthesized using click chemistry and evaluated in vitro. In terms of labeling, click chemistry was superior to conventional chemistry, due to a higher decay-corrected radiochemical yield (30% vs. 21%), higher specific activity (59.9 GBq/&micro;mol vs. 23.5 GBq/&micro;mol), and shorter synthesis time (75-80 min vs. 95-100 min). In vitro evaluation demonstrated that [18F]1 does not act as a hexokinase substrate and has low and non-specific uptake by SNU-C5 cells. These results suggest that click chemistry offers a rapid and efficient radiolabeling method which does not require the protection of functional groups, although a triazole moiety at C1 of [18F]1 is incompatible for hexokinase phosphorylation and facilitative diffusion via Glut-1. Fatty acids are substrates for energy metabolism in myocardium. Therefore, radiolabeled fatty acid analogs are useful for evaluation of fatty acid metabolism in myocardium. In this study, we synthesized 17-[4-(2-[18F]fluoroethyl)-1H-1,2,3-triazol-1-yl]-6-thia-heptadecanoic acid ([18F]6) for the evaluation of fatty acid metabolism. Radiotracer [18F]6 was synthesized in 20-26% decay-corrected yields from 17-azido-6-thia-heptadecanoic acid and 4-[18F]fluoro-1-butyne using click chemistry. The tissue distribution of [18F]6 in mice showed high radioactivity accumulation in heart (3.28 % ID/g at 10 min and 3.01 %ID/g at 60 min post-injection), a prolonged myocardial elimination half-life (> 60 min), and a maximal heart to blood uptake ratio at 5 min post-injection (6.49). Pretreatment with etomoxir, a carnitine palmitoyl transferase (CPT) I inhibitor reduced myocardial radioactivity uptake at 30 min post-injection by 53%. Analyses of heart tissue samples showed that most of the radioactivity was present in tissue pellet (62-63%). These results suggest that [18F]6 undergoes metabolic trapping via β-oxidation in myocardium, and thus, suggest that it has potential use as a PET radiotracer for the evaluation of myocardial fatty acid metabolism. The αvβ3 integrin is expressed on proliferating endothelial cells and tumor cells of various origin. We synthesized a 17-[4-(2-[18F]fluoroethyl)-1H-1,2,3-triazole-1-yl]-5-oxo-9,12,15-trioxa-6-azaheptadecano-E[c(RGDyK)]2 ([18F]22) for minitoring αvβ3 integrin expression on tumor cells. The precursor was synthesized by conjugating 17-azido-5-oxo-9,12,15-trioxa-6-azaheptadecanoyl-NHS ester with E[c(RGDyK)2]. Radiotracer [18F]22 was prepared from 17-azido-RGD dimer and 4-[18F]fluoro-1-butyne using click chemistry and purified by reverse phase HPLC. Decay-corrected radiochemical yield of [18F]22 was 12-16% and total synthesis time including HPLC purification was 70-75 min. 의약품 개발을 위하여 생활성을 가지는 새로운 화합물을 개발하는 것은 매우 중요한 과제이다. 하지만 생활성 물질을 개발하는 것은 비용, 많은 시간, 그리고 복잡한 합성경로로 인한 많은 문제들을 포함하고 있다. 같은 맥락으로, 핵의학 진단을 목적으로 한 방사성의약품들은 동시에 병소에 특이적인 성질을 지녀야 하므로 새로운 방사성의약품의 개발은 매우 어려운 일이다. Click chemistry는 반응이 위치선택적이며 생성물의 수율이 높고 일반적으로 보호기의 관여가 없는 장점을 가지고 있어서 다양한 종류의 트리아졸 화합물을 합성할 수 있다. 이 연구에서는 아자이드 화합물과의 click chemistry를 위한 synthon으로4-[18F]fluoro-1-butyne을 개발하였으며, 이 방사성 알킨을 이용하여 새로운 방사성추적자들(글루코스, 지방산, RGD 펩타이드 유사체)을 합성하고 생물학적 유용성을 평가하였다. 방사성동위원소로 표지된 글루코스 유사체는 대사영상에 사용되는 방사성추적자이다. 이 연구에서는 click chemistry를 이용하여 4-[(2-[18F]fluoroethyl)-1-(β-D-glucopyranosyl)]-1H-1,2,3-triazole ([18F]1)를 합성하고 체외 평가를 수행하였다. 새로운 방사성추적자인 글루코스 유사체는 두 가지 방법으로 합성하였다. 토실레이트 전구물질을 사용하는 고전적인 표지방법과 click chemistry 방법을 이용하였다. 방사화학적 수율 및 비방사능 측면에서 후자의 방법이 우세하였으며 합성시간도 15분을 단축할 수 있었다. 이 결과는 [18F]1의 1번 탄소 위치에 트리아졸기가 치환되면 헥소키나제 인산화 및 Glut-1을 이용한 운반에 적합하지 않지만, click chemistry가 기능기의 보호가 필요하지 않은 빠르고 효율적인 표지방법이라는 것을 보여주었다. 지방산은 심근에서 에너지 대사를 위한 주요한 기질이다. 이 연구에서는 지방산 유사체로서 17-[4-(2-[18F]fluoroethyl)-1H-1,2,3-triazol-1-yl]-6-thia-heptadecanoic acid ([18F]6)를 합성하였으며 심근에서 지방산 대사를 위한 방사성추적자로서의 가능성을 평가하였다. [18F]6은 click chemistry를 사용하여 17-azido 6-thia-heptadecanoic acid와 4-[18F]fluoro-1-butyne로부터 20-26%의 수율로 합성되었다. 마우스의 체내분포 결과 심장에서 높은 섭취를 보였고(주사 후 1분에 3.70 %ID/g, 10분에 3.28 % ID/g), 심장에서의 방사능 배출 반감기는 60분 이상 이었으며, 심장 대 혈액 섭취비는 5분에서 6.49이었다. 카르니틴 팔미토일 트란스퍼라제(CPT) I 억제제인 에토목시어를 전처리한 마우스에서 심근의 방사능 섭취가 주사 후 30분에 53% 감소하였다. 또한 심장 조직의 분석은 대부분의 방사능이 조직 추출 후 남은 잔여물에 존재하였다(62-63%). 이 결과는 [18F]6이 심근에서 베타-산화를 통하여 대사적으로 포집되었음을 제시한다. 그러므로 [18F]6은 심근의 지방산 대사의 평가를 위한 PET 방사성추적자로서 가능성을 보였다. αvβ3 인테그린은 종양으로부터 방출된 단백질이 혈관형성을 유도할 때 수용체 역할을 담당하는 단백질이다. Arg-Gly-Asp (RGD)를 포함하는 펩타이드는 이 수용체에 특이적으로 결합하는 화합물로 알려져 있다. 이 연구에서는 종양세포의 αvβ3 인테그린의 발현을 모니터링하기 위하여 click chemistry를 사용하여 17-azido-cRGD dimer와 4-[18F]fluoro-1-butyne로부터 17-[4-(2-[18F]fluoroethyl)-1H-1,2,3-triazole-1-yl]-5-oxo- 9,12,15-trioxa- 6-azahepta- decano-E[c(RGDyK)]2 ([18F]22)를 합성하였다. 18F-표지를 위한 전구물질은 E[c(RGDyK)2]에 17-azido-5-oxo-9,12,15-trioxa-6-azaheptadecanoyl-NHS ester를 접합하여 합성하였다. [18F]22의 방사화학적 수율은 12-16%이었으며 HPLC 정제를 포함한 총 합성시간은 70-75분이었다.

Influence of turbulent transport and chemistry on the distribution of H_(2)O_(2), CH_(3)OOH, and HCHO in the remote marine boundary layer

장원일 University of Rhode Island 2002 해외박사

This study is motivated by the discrepancies found between observational data, collected in the marine boundary layer (MBL) during several large scale field campaigns, and photochemical model simulations appropriate to these campaigns. In particular, for the principal chemical species (H_(2)O_(2), CH_(3)OOH, and HCHO) theory and measurement remain unresolved. The temporal and spatial distribution and behavior of these key species indicates they are subject to chemical and physical processes such as gas-phase chemistry, scavenging by seasalt particles, seasalt aerosol chemistry involving halogen species, air-sea gas exchange, and FT-MBL exchange. We hypothesize that the incorporation of these processes into a single model will resolve the discrepancies. A one-dimensional photochemical model is developed which contains all processes to test this concept. A series of model simulations were conducted with varied model chemistry and material boundary flux conditions. The observational data (collected in the equatorial MBL during the PEM-Tropics (B) field program) were compared with the model results. The results indicate that two processes; 1) the FT-to-MBL O_(2) transport and 2) dry deposition critically influence the abundance of the key species. The results show that gas-phase chemistry alone with rationalized flux conditions is capable of capturing the behavior of CH_(3)OOH and HCHO and other processes (scavenging by seasalt particles and seasalt aerosol chemistry involving halogen species) are found to be negligible under PEM-Tropics (B) conditions. The comparisons show general agreement between the observations and theory for O_(3), OH, CH_(3)OOH, HCHO, NO_(x), and SO_(2). There remain gaps in our understanding of other species such as H_(2)O_(2), CH_(3)OH, DMS, and total nitrate (HNO_(3) + NO_(3)^(-)).

THE EFFECTS OF CONTEXT-BASED LEARNING APPROACH ON CAMEROON HIGH SCHOOL STUDENTS’ INTEREST, ATTITUDE AND MOTIVATION IN CHEMISTRY

도라 한국교원대학교 대학원 2020 국내석사

이 연구는 맥락 연구 (CBL) 접근법이 화학 연구에 대한 고등학생의 관심에 미치는 영향을 결정하는 것을 목표로합니다. 이 혼합 연구는 카메룬에있는 공립 고등학교 60 명의 학생들을 대상으로했습니다. 실험 그룹은 6 주 동안 CBL을 통해 진행되는 반면, 이들은 전통적인 접근 방식으로 통제 그룹을 가르치는 두 개의 동일한 그룹으로 나뉘 었습니다. 이 혼합 연구에서 사전 테스트 및 사후 테스트 설문 조사는 양적 데이터를 제공했으며 인터뷰 및 교실 관찰은 정 성적 데이터를 제공했습니다. 분석 결과, 남녀의 관심 수준에 차이가없는 실험군에 대한 관심이 크게 증가한 것으로 나타 났으며 교과서 나 컴퓨터를 집에서 사용하는 사람과 그렇지 않은 사람 사이에는 차이가 없었습니다. 학생들은 다음과 같은 흥미로운 것을 발견했습니다. 화학, 생활 및 온라인 학습과 관련된 수업에서 다양한 활동을 수행합니다. CBL은 먼저 화학에 대한 태도를 바꾸고 화학을 공부하려는 동기를 증가시킴으로써 학생들의 관심을 높이는 데 효과적이었습니다. 이것은 화학 내용의 이해와 기억의 증가, 학생들의 의사 소통, 문제 해결 및 비판적 사고 능력 개발을 통해 이루어졌습니다. 수업은 즐겁고 재미 있었지만, 학생들은 개인 학습이 매우 어려운 측면을 발견했습니다. 교사에게는 상황을 선택하는 것이 어려웠고 시간이 많이 걸렸습니다. 일부 수업에서는 학생의 생활과 관련된 상황을 찾을 수 없었기 때문입니다. This study aims to determine the effects of context-based learning (CBL) approach on high school students' interest, attitude, and motivation in studying chemistry. This mixed study involved 60 students in a government high school in Cameroon. They were divided into two equal groups the control group was taught with the traditional approach while the experimental group was taught through CBL for 6 weeks. In this mixed study, a pretest and posttest survey provided quantitative data while interview and classroom observation provided qualitative data. The results of the analysis indicated a significant increase in interest, attitude, and motivation in the experimental group with no difference in the level of interest, attitude, and motivation among males and females neither was there a difference among those who had textbooks or used computers at home and those who did not. The students found the following interesting; carrying out various activities in chemistry, lessons that relate to their lives and online learning. CBL was effective in increasing students’ interest by first changing their attitude towards chemistry and increasing their motivation to study chemistry. This occurred through an increase in the understanding and recall of chemistry content, and developing communication, problem-solving and critical thinking skills in the students. Though the classes were enjoyable and fun, the students found individual learning a very challenging aspect. To the teacher, selecting context was difficult and time-consuming because, for some lessons, he could not find a context that is relevant to students' life.

화학과 교육과정의 실행에서 나타난 연계성 부족에 대한 연구 : 대학교수와 대학생의 인식을 중심으로

백은숙 서울대학교 대학원 2020 국내박사

본 연구는 2009 개정 교육과정의 고등학교 화학과 대학교 일반화학의 연계성에 대한 대학교수들과 대학생들의 인식을 분석하여, 교육 현장에 2015 개정 교육과정이 적용될 때 연계성 확보 측면에서 발전적인 방안 및 시사점을 제시하고자 하였다. 이를 위해서 대학교 화학과에서 일반화학을 강의한 대학교수 10인을 선정하였고, 교수자로서 강의 경험을 바탕으로 심층적인 면담을 통해서 자료를 수집하였다. 또한, 고등학교 화학과 대학교의 일반화학을 학습한 대학생 8명을 대상으로 사례연구를 수행하였다. 그리고 일반화학 강의를 수강한 대학생 75명을 대상으로 설문 조사를 실시하였으며, 설문 결과를 연구 자료로 활용하여 연구문제를 비교 및 검토하였다. 연구의 결과 첫째, 대학교수들과 대학생들은 대부분 2009 개정 교육과정 고등학교 화학과 대학교 일반화학의 교과 내용의 연계는 잘 되고 있다고 인식하였으나, 고등학교 현장에서 실행된 교육과정의 화학과 대학교 일반화학 사이의 연계성은 부족한 것으로 응답하였다. 둘째, 대학교수들은 ‘대학생들의 고등학교 과학과 선택과목’이 일반화학 강의 방향에 영향을 많이 준다고 인식하였다. 다수의 학생들은 ‘점수를 잘 받기 위해서’ 혹은 ‘고등학교에서 수강인원이 적은 과목을 개설해주지 않았기 때문에’ 수능에서 화학Ⅱ를 선택하지 않았다. 그 결과 대학생들이 대학교의 일반화학을 학습하는 데에 있어서 큰 어려움을 겪는 것으로 나타났다. 셋째, 본 연구는 일반화학의 내용 중에 대학생들이 어려워하는 단원을 수직적·수평적 연계성 측면으로 분석하였고, 이에 따라 화학Ⅰ, 화학Ⅱ, 일반화학 사이의 내용체계에 대한 연계성을 파악할 수 있었다. 넷째, 2015 개정 교육과정의 고등학교와 대학교의 화학과 교육과정의 연계성 확보를 위하여 대학교수들과 대학생들은 고등학교 선택교과 및 대학 입시제도의 개선, 충실한 기초개념의 학습 등의 필요성을 제시하였다. 그리고 본 연구는 일반화학을 구성하는 중단원의 개념을 적용하여 2009 개정 교육과정의 과학, 화학Ⅰ, 화학Ⅱ와 2015 개정 교육과정의 통합과학, 화학Ⅰ, 화학Ⅱ를 구성하는 내용요소 및 내용체계를 총체적으로 분석하였다. 이에 따라 화학과 교육과정의 내용체계에 대한 새로운 모식도 및 모델을 제시하였다. 이를 바탕으로 화학과 교육과정의 연계성 부족에 대한 시사점 및 대안을 제시하고자 하였다. The purpose of this study is to analyze the perceptions of professors and university students about the connection between high school chemistry and general chemistry in the 2009 revised curriculum and to suggest the developmental measures and implications for securing the connection when the 2015 revised curriculum is applied to the educational field. For this purpose, ten university professors who taught General Chemistry at the department of chemistry were selected, and the data were collected through in-depth interviews based on the lecture experience. Also, a case study was conducted for eight university students who had studied high school Chemistry and General Chemistry. And responses from 75 university students were reviewed and compared according to the research questions. As a result, first, most university professors and university students perceived that the curriculum content of high school chemistry of the 2009 revised curriculum seemed to be well related to General Chemistry. But they perceived that the connection between Chemistry and General Chemistry was insufficient in the curriculum implemented on school sites. Second, university professors perceived that ‘the science subjects that university students chose in high school’ influenced the direction of General Chemistry lectures. Many high school students do not choose ChemistryⅡ in the College Scholastic Ability Test (CSAT) because they try to get good scores and high school did not support classes to a small number of students. These results show that university students have significant difficulty in learning General Chemistry at universities. Third, this study analyzed the vertical and horizontal connection aspects of chapters that university students think difficult in General Chemistry. Accordingly, I figured out the connection in the content system among ChemistryⅠ, ChemistryⅡ, and General Chemistry. Fourth, to secure the connection between high school and university chemistry subjects in the 2015 revised curriculum, university professors and university students have suggested the improvement for the optional curriculum and the admissions system, and the study of faithful basic concepts. In addition, this study shows comprehensive analysis of the content elements and content systems that consist of Science, ChemistryⅠ, and ChemistryⅡ of the 2009 revised curriculum and Integrated Science, ChemistryⅠ, and ChemistryⅡ of the 2015 revised curriculum by applying the concept of an intermediate chapter used in General Chemistry. Accordingly, a new schematic diagram and model for the content system of the chemistry curriculum were presented. Based on this, it was intended to suggest implications and alternatives to the insufficiency of connection in the chemistry curriculum.

Two-dimension property based advanced functionality in material electronics

이한림 성균관대학교 일반대학원 2017 국내박사

Nanomaterials has been paid attention to many researchers and spread throughout different field such as chemistry, physics, materials science, engineering, and biology. Nanoscale materials present not only intrinsic properties of bulk materials, but also a new realm of matter. Sometimes, nano-materials allow to investigate interesting basic science in mild condition as well as provide useful technologies for society. In spite of all this advantages, realizing the nano-materials with desired features is not easy because the basic chemistry of nano-materials is not sufficient either synthetic approach or chemical reaction in specific system. There is a need for a research about fundamental quantum chemistry that serves the basic science community, especially chemists. At this point, we have studied on quantum chemistry of nano-materials. Among 0D to 2D materials, 2D materials have been intensively focused due to their numerous chemical potential like spatial selectivity, different physical properties along the axis, and various feasibility to modify active site. Thus, the quantum chemistry of 2D materials is powerful method to design novel materials with unique and superior properties. In the first chapter, we introduce a general overview of background for nano-dimension materials, including classification and differences from bulk materials and discuss what makes the nano-materials so special. One of reason seems to be distinctive intrinsic properties of nano-scale materials, especially electrical and optical properties, so it is described in aspect of quantum physics. Second reason is unique chemistry unlike bulk chemistry or surface chemistry. However, the basic science of quantum chemistry in nano-materials is not fully investigated so we focus on introducing various chemical reaction which have been studied. For the second chapter, we suggest several spatial selective quantum chemistry. Firstly, spatial selective quantum chemistry is applied to develop new soft channel materials for field effect transistor which can overcome the limited on/off ratio and carrier mobility due to the low crystalline of material by chemical treatment pre- and post-fabrication of device. The edge functionalization is realized by engineering reaction environment and associated device demonstrate high performance. Secondly, 3D configuration electrode is demonstrated through spatial selective quantum chemistry. Self assembly monolayer of carbon precursor facilitate the formation of graphene as a candidate for the 3D electrode owing to its high electron mobility, high thermal conductivity, and high mechanical strength. The third chapter of this dissertation, we focus on surface selective quantum chemistry related to new chemistry of nano-dimensional materials. New pathway to enhance electro-catalytic effect of 2D materials unlike the way such as conductivity or surface area is developed through surface functionalization. The surface functionalization also affects to the electrical properties of nanomaterials corresponding to the substituent effects of organic moiety. The effective molecular doping facilitate to produce ohmic contact p-n diode. Moreover, mechanical properties is modulated by chemical treatment on surface. Both cases, strong hydrogen bonding between hydrophilic surface and 2D graphene oxide and complex bonding between amine modified surface and AgNW, enhance transmittance and resistance of flexible electrode. The fourth chapter explains the chemical and physical properties modulation through composition configuration of 2D materials. Nanoparticle doped 2D material is designed for photo-sensitive composite and polymer mediated 2D material is developed for mechanically stable composite