• Title/Summary/Keyword: Chemistry education

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Cathode interface engineering for stable and efficient organic light-emitting diodes

  • Qiu, Yong;Duan, Lian;Li, Yang
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1199-1202
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    • 2007
  • The improvement of the electron injection is of critical importance for obtaining efficient and stable organic light-emitting diodes(OLEDs). Here, we report some of our recent results on the development of new cathode interlayer materials for OLEDs. Some of our new materials show performance superior to that of LiF.

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An Investigation of the Types of Student-Generated Analogies, the Mapping Understanding, and the Mapping Errors in Concept Learning on the Reaction Rate with Generating Analogy (비유 만들기를 활용한 반응속도 개념 학습에서 학생들이 만든 비유의 유형과 대응 관계 이해도 및 대응 오류 조사)

Investigation of Undergraduate Students' Understanding on Fundamental Chemical Reaction Based on Electron Flow (전자 흐름에 기초한 기초적인 화학 반응에 관한 대학생들의 이해도 조사)

  • Lee, Sang-Gwon;Gwon, Jeong-Gyun;Kim, Gyeong-Mi;Park, Guk-Tae
    • Journal of the Korean Chemical Society
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    • v.46 no.3
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    • pp.279-286
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    • 2002
  • The purpose of this study was to investigate undergraduate students' preconception about the needed knowledge to understand organic reactions based on electron flow and undergraduate students' ability that understand fundamental chemical reaction based on electron flow, and was to offer pertinent teaching and learning method. For this study, 18 sophomores that majored in chemistry education of H University, were sampled. Test papers were newly developed that based on previous research. Undergraduate students' response was classified and reasons of the response were qualitatively analyzed by interview. According to the results of this study, it was found that undergraduate students had good understanding on the concept about the electron configuration of atoms and on the concepts about the needed knowledge to understand chemical reactions based on electron flow. But they didn't apply the concepts to the fundamental chemical reaction. Therefore, teaching and learning strategy that apply the needed concepts to understand chemical reactions based on electron flow to chemical reactions should be developed.

Analysis of Changes in Preservice Science Teachers’ Modeling Ability in Argument-based General Chemistry Laboratory Investigations (논의 기반 일반화학 실험과정에서 예비과학교사들의 모델링 능력 변화과정 분석)

  • Kang, Yeo Eun;Nam, Jeonghee;Cho, Hey Sook
    • Journal of the Korean Chemical Society
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    • v.60 no.4
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    • pp.276-285
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    • 2016
  • This study aimed to examine preservice science teachers' modeling ability and how it has changed in argument-based chemistry laboratory investigations. The participants for this study were twenty-one freshman students from teachers’ college and they carried out six topics of argument-based chemistry laboratory investigation. Students’ written modeling samples were collected and analyzed to investigate preservice science teacher's modeling ability and changes in it. The results of this study showed that preservice science teacher's modeling ability has improved and progressed through argument-based chemistry laboratory investigations.

31P NMR and ESI-MS Study of Fenitrothion-Copper Ion Complex: Experimental and Theoretical Study

  • Choi, Ho-June;Yang, Ki-Yull;Park, Jong-Keun;Koo, In-Sun
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1339-1342
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    • 2010
  • $^{31}P$ NMR and ESI-MS studies of $Cu^{2+}$ binding to Fenitrothion (FN) were performed by experimentally and theoretically. The calculated $^{31}P$ NMR chemical shifts for FN-$Cu^{2+}$ complexes are in good agreement with experimental chemical shifts in order, and the results present an important information for organophosphorus pesticide metal complexes. ESI-MS and low energy CID MS/MS experiments of FN-$Cu^{2+}$ complexes combined with accurate mass measurements give insight into the metal localization and allow unambiguous identification of fragments and hydrolysis products.

Efficient organic light-emitting diodes with Teflon buffer layer

  • Zhang, Deqiang;Gao, Yudi;Wang, Liduo;Qiu, Yong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.269-271
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    • 2004
  • In this report, high-performance organic light-emitting diodes (OLEDs) with polytetrafluoroethylene (Teflon) buffer layer are demonstrated. Compared with conventional buffer layer, copper phthalocaynine (CuPc), Teflon film shows lower absorption in the wavelength from 200nm to 800nm The OLEDs with Teflon and CuPc buffer layer were fabricated under same conditions, and the device performances were compared. The results indicate that when the thickness of Teflon is 1.5nm, the performance of OLEDs is greatly enhanced with an efficiency of 9.0cd/A at the current density of 100mA/$cm^2$, while the device with an optimized 30-nm-thick CuPc buffer layer only shows an efficiency of6.4cd/A at the same current density.

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