• Title/Summary/Keyword: Chemical education

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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.

  • https://doi.org/10.5012/jkcs.2002.46.3.279 인용 PDF KSCI

A Study on HF Chemical Passivation for Crystalline Silicon Solar Cell Application (결정질 태양전지를 위한 HF 화학 패시베이션 연구)

  • Choi, Jeong-Ho;Roh, Si-Cheol;Yu, Dong-Yeol;Li, Zhen-Hua;Kim, Yeong-Cheol;Seo, Hwa-Il
    • Journal of the Semiconductor & Display Technology
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    • v.10 no.1
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    • pp.51-55
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    • 2011

  • The surface passivation is one of the important methods that can improve the efficiency of solar cells and can be classified into two methods: wet-chemical passivation and film passivation. In this paper, chemical HF treatment were employed for the passivation of n-type silicon wafers and their effects were studied. To investigate film passivation effects, the silicon nitride films were also deposited by PECVD (plasma-enhanced chemical vapor deposition) on n-type silicon wafers treated with chemical HF. The minority carrier lifetime measurements were used for evaluation of the passivation characteristics in the all experiments steps. We confirmed that the minority carrier lifetime was improved with chemical HF treatment due to passivation effects by H-termination.

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Performance Evaluation of Hazardous Substances using Measurement Vehicle of Field Mode through Emergency Response of Chemical Incidents

  • Lee, Yeon-Hee;Hwang, Seung-Ryul;Kim, Jae-Young;Kim, Kyun;Kwak, Ji Hyun;Kim, Min Sun;Park, Joong Don;Jeon, Junho;Kim, Ki Joon;Lee, Jin Hwan
    • Korean Journal of Environmental Agriculture
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    • v.34 no.4
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    • pp.294-302
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    • 2015

  • BACKGROUND: Chemical accidents have increased owing to chemical usage, human error and technical failures during the last decades. Many countries have organized supervisory authorities in charge of enforcing related rules and regulations to prevent chemical accidents. A very important part in chemical accidents has been coping with comprehensive first aid tool. Therefore, the present research has provided information with the initial applications concern to the rapid analysis of hazardous material using instruments in vehicle of field mode after chemical accidents. METHODS AND RESULTS: Mobile measurement vehicle was manufactured to obtain information regarding field assessments of chemical accidents. This vehicle was equipped with four instruments including gas chromatography with mass spectrometry (GC/MS), Fourier Transform Infrared Spectroscopy (FT-IR), Ion Chromatography (IC), and UV/Vis spectrometer (UV) to analyses of accident preparedness substances, volatile compounds, and organic gases. Moreover, this work was the first examined the evaluation of applicability for analysis instruments using 20 chemicals in various accident preparedness substances (GC/MS; 6 chemicals, FT-IR; 2 chemicals, IC; 11 chemicals, and UV; 1 chemical) and their calibration curves were obtained with high linearity ( r 2 > 0.991). Our results were observed the advantage of the high chromatographic peak capacity, fast analysis, and good sensitivity as well as resolution. CONCLUSION: When chemical accidents are occurred, the posted measurement vehicle may be utilized as tool an effective for qualitative and quantitative information in the scene of an accident owing to the rapid analysis of hazardous material.

  • https://doi.org/10.5338/KJEA.2015.34.4.36 인용 PDF KSCI KPUBS HTML

A Study on Thermal Conductive Acrylic Pressure Sensitive Adhesive with Alumina and Graphite (알루미나와 흑연을 포함하는 열전도성 아크릴 점착제의 연구)

  • Oh, Ji Hwan;Jang, Sun Ho;Yoo, Seong Sik;Cho, Ryong
    • Journal of the Semiconductor & Display Technology
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    • v.16 no.3
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    • pp.93-98
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    • 2017

  • 2-Ethylhexyl acrylate, butyl acrylate, methyl methacrylate, and 2-hydroxyethyl methacrylate were polymerized to synthesize acrylic pressure sensitive adhesive (PSA). Alumina and graphite as a filler were added to acrylic PSA to give thermal conductivity. In case of addition of both graphite and alumina, the thermal conductivity of PSA was increased compared with alumina alone due to enhancement of contact between two fillers followed by increasing thermal path in PSA matrix.

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