MnO₂-HCS 복합체를 이용한 슈퍼커패시터의 전기화학적 특성

김은미,정상문,Jin, En Mei,Jeong, Sang Mun 한국청정기술학회 2018 청정기술 Vol.24 No.3

중공형 구형 탄소(hollow carbon spheres, HCS) 또는 구형 탄소(carbon spheres, CS)는 수열합성법에 의해 제조되었고 $MnO_2$를 증착하기 위한 탄소 지지체로 사용하였다. $MnO_2$는 화학적 레독스 증착법에 의해 HCS 또는 CS 표면에 증착하였다. 화학적 산화환원 증착법은 미립자 지지체의 표면에 다른 산화물 합성에 특히 효과적이다. $MnO_2$는 HCS 또는 CS의 표면에 일정한 슬릿 모양의 분포를 보였고 HCS 표면에서 보다 엉성한 슬릿 모양의 $MnO_2$ 입자가 생성되었다. $MnO_2-HCS$는 $20mv\;s^{-1}$의 스캔 속도에서 초기 사이클에서 약 $164.1F\;g^{-1}$의 정전용량을 나타내었고 1000 사이클 후에는 약 $141.3F\;g^{-1}$의 정전용량을 나타내었다. 1000 사이클 기준으로 $MnO_2-HCS$와 $MnO_2-CS$는 각각 86%와 78%의 용량유지율을 나타내었다. 이것은 HCS 표면에서 엉성한 슬릿모양의 $MnO_2$의 성장이 전해질의 흐름 및 전해질 내의 $Na^+$ 이온의 흡탈착이 보다 용이하여 나타난 결과로 생각된다. Hollow carbon spheres (HCS) and carbon spheres (CS) were prepared by a hydrothermal reaction and they were introduced as a substrate for the deposition of $MnO_2$ nanoparticles. The $MnO_2$ nanoparticles were deposited on the carbon surface by a chemical redox deposition method. After deposition, the $MnO_2$ nanoparticles were uniformally distributed on the carbon surface in a slit-shape, and sparse $MnO_2$ slits appeared on the HCS surface. The $MnO_2-HCS$ showed an initial specific capacitance of $164.1F\;g^{-1}$ at scan rate of $20mv\;s^{-1}$, and after 1,000 cycles, the specific capacitance was maintained to $141.3F\;g^{-1}$. The capacity retention of $MnO_2-HCS$ and $MnO_2-CS$ were calculated to 86% and 78% in the cycle performance test up to 1,000 cycles, respectively. $MnO_2-HCS$ showed a good cycle stability due to the mesoporous hollow structure which can cause a faster diffusion of the electrolyte and can easily adsorb and desorb $Na^+$ ions on the surface of the electrode.

분산특성이 향상된 고효율 염료감응형 태양전지

김은미,박경희,구할본,박복기,Jin, En-Mei,Park, Kyung-Hee,Gu, Hal-Bon,Park, Bok-Kee 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.6

$TiO_2$ nano-particle paste was prepared by ethyl cellulose, $\alpha$-terpineol and bis(2-ethylhexyl) phthalate (dioxcyl phthalate) for dye-sensitized solar cells (DSSCs). Dispersion and absorbance of $TiO_2$ photoanode films was controlled by adding different amount of ethyl cellulose and $\alpha$-terpineol. The morphology of prepared $TiO_2$ films was studied by field emission scanning electron microscopy (FE-SEM) and the optical properties of $TiO_2$ films were measured by UV/vis spectra. Photovoltaic-current density was observed to determine the electrochemical response of DSSCs. Energy conversion efficiency was obtained about 7.1% at ethyl cellulose and $\alpha$-terpineol at optimal mixed ratio (as ethyl cellulose: 0.1 g; $\alpha$-terpineol: 1.5 ml) under illumination with AM 1.5($100\;Wcm^{-2}$) simulated sunlight.

Purification, Structure Determination and Biological Activities of 20(29)-lupen-3-one from Daedaleopsis tricolor(Bull.ex Fr.)Bond.et Sing.

김은미,정해룡,민태진,Kim, Eun Mi,Jeong, Hae Ryong,Min, Tae Jin Korean Chemical Society 2001 Bulletin of the Korean Chemical Society Vol.22 No.1

The dried fruit-body of Daedaleopsis tricolor was extracted by the petroleum ether. The extracts were purified by liquid-liquid extraction, column chromatography, and recrystallization. The purified compound was a colorless orthorhombic crystal form. Its melting point, molecular weight and molar extinction coefficient $(\varepsilon)$ were estimated $168-170^{\circ}C$, 424 and 3,935 at 208 nm, respectively. Its structure was elucidated to be 20(29)-lupen-3-one by UV-Vis, FT-IR, NMR and X-ray crystallographic analysis. It showed antifungal activities against Saccharomyces cerevisiae and Microsporum gypseum, and antibacterial activities against Escherichia coli, Proteus vulgaris, Pseudomonas pyocyanea, Bacillus subtilis, and Staphylococcus aureus. In addition, this compound showed an antioxidative activity on lipid-peroxidation by 6.4%.

표고버섯의 미토콘드리아성 NADH 탈수소효소의 특성

김은미,민지영,민태진 ( Eun Mi Kim,Ji Young Min,Tae Jin Min ) 한국균학회 1998 韓國菌學會誌 Vol.26 No.1

Si기판 위에 Ba_0.5Sr_0.5TiO₃ 산화물 에피 박막의 집적화 및 박막의 유전 특성에 관한 연구

김은미,문종하,이원재,김진혁,Kim, Eun-Mi,Moon, Jong-Ha,Lee, Won-Jae,Kim, Jin-Hyeok 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.6

Epitaxial $Ba_{0.5}Sr_{0.5}TiO_3$ (BSTO) thin films have been grown on TiN buffered Si (001) substrates by Pulsed Laser Deposition (PLD) method and the effects of substrate temperature and oxygen partial pressure during the deposition on their dielectric properties and crystallinity were investigated. The crystal orientation, epitaxy nature, and microstructure of oxide thin films were investigated using X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Thin films were prepared with laser fluence of $4.2\;J/cm^2\;and\;3\;J/cm^2$, repetition rate of 8 Hz and 10 Hz, substrate temperatures of $700^{\circ}C$ and ranging from $350^{\circ}C\;to\;700^{\circ}C$ for TiN and oxide respectively. BSTO thin-films were grown on TiN-buffered Si substrates at various oxygen partial pressure ranging from $1{\times}10^{-4}$ torr to $1{\times}10^{-5}$ torr. The TiN buffer layer and BSTO thin films were grown with cube-on-cube epitaxial orientation relationship of $[110](001)_{BSTO}{\parallel}[110](001)_{TiN}{\parallel}[110](001)_{Si}$. The crystallinity of BSTO thin films was improved with increasing substrate temperature. C-axis lattice parameters of BSTO thin films, calculated from XRD ${\theta}-2{\theta}$ scans, decreased from 0.408 m to 0.404 nm and the dielectric constants of BSTO epitaxial thin films increased from 440 to 938 with increasing processing oxygen partial pressure.

Evaluating Choice Attributes of Korean Ginseng Chicken Soup as a Home Meal Replacement (HMR) Product Using Conjoint Analysis: A Case Study of Singapore Market

김은미,안지애,이호진,이민아,Kim, Eun-Mi,Ahn, Jee-Ahe,Lee, Ho-Jin,Lee, Min-A Korean Society of Food and Cookery Science 2016 한국식품조리과학회지 Vol.32 No.5

목적: 세계 식품시장에서 한식과 편이식에 대한 니즈가 점차 증가함에 따라 싱가포르 시장은 한식을 이용한 간편가정식(HMR)의 잠재시장으로 떠오르고 있다. 다양한 한식 메뉴 중에서도 특히 삼계탕은 싱가포르 소비자의 선호도가 매우 높아 본 연구에서는 컨조인트 분석을 적용하여 삼계탕 HMR 선택 속성의 중요도를 분석하고자 하였다. 연구방법: 2012년 4월 싱가포르 현지 소비자 400명을 대상으로 설문지를 배포하였으며, 이 중 설문을 완료한 324명(81.0%)의 데이터를 분석하였다. 결과: 삼계탕 HMR을 구매하는데 있어 상대적으로 가장 중요한 속성으로는 포장(32.4%)이었고, 닭의 형태(32.1%), 찹쌀 포함 여부(13.8%), 삼계탕의 풍미(11.6%)와 인삼(10.0%)의 순서로 조사되었다. 제시된 16개 프로파일 중 제품 코드 J의 닭 반마리, 찹쌀 포함, 인삼 전체 한 뿌리 포함된 형태, 간장 육수, 그리고 제품이 부분적으로 보이도록 투명한 포장형태로 구성된 제품의 선호도가 가장 높은 것으로 조사되었다. 또한 초이스 시물레이션 분석을 통해, 싱가포르 소비자가 가장 선호하는 삼계탕 HMR이 출시될 경우 예상되는 시장 점유율은 50.4%로 나타났다. 결론: 이러한 조사 결과는 외국인 소비자의 보다 세분화된 니즈를 반영한 한식 상품을 개발하는데 구체적인 자료를 제공하며, 식품 산업적으로도 소비자 기호를 반영한 상품을 출시 할 수 있을 것으로 판단된다. 더불어 향후 한식 간편 가정식 개발이 더욱 활성화 됨에 따라, 한식 세계화에 따른 한식의 소비 확대에 보다 실제적인 적용이 가능할 것으로 사료된다. Purpose: The purpose of this study was to analyze the attributes considered important by Singaporeans in the selection of Korean ginseng chicken soup as an HMR product using conjoint analysis techniques. Methods: A total of 400 questionnaires were distributed to local consumers in April 2012, of which 324 were completed (81.0%). Statistical analyses of data were performed using SPSS/Windows 18.0 for descriptive statistics and conjoint analysis. Results: Analysis of the attributes and levels of Korean ginseng chicken soup as an HMR product for people who lived in Singapore showed the relative importance of each attribute as follows: packing (32.4%), chicken (32.1%), glutinous rice (13.8%), soup (11.6%), and ginseng (10.0%). Results showed that Singaporean consumers preferred code J's Korean ginseng chicken soups as an HMR product, which consisted of half a chicken, glutinous rice, a whole ginseng root in a soy sauce-based soup, and a partially transparent package. The most preferred Korean ginseng chicken soup gained 50.4% potential market share from choice simulation when compared with the second preferred one. Conclusion: This study has significance in that such a practical research contributes to product development of a specific Korean dish for foreign consumers. In addition, the results of this study provide useful information for the food industry for global expansion and commercialization of Korean food, thereby providing an important foundation for future development of various Korean foods as HMR products.

MnO₂-HCS 복합체를 이용한 슈퍼커패시터의 전기화학적 특성

김은미(En Mei Jin),정상문(Sang Mun Jeong) 한국청정기술학회 2018 청정기술 Vol.24 No.3

중공형 구형 탄소(hollow carbon spheres, HCS) 또는 구형 탄소(carbon spheres, CS)는 수열합성법에 의해 제조되었고 MnO₂를 증착하기 위한 탄소 지지체로 사용하였다. MnO₂는 화학적 레독스 증착법에 의해 HCS 또는 CS 표면에 증착하였다. 화학적 산화환원 증착법은 미립자 지지체의 표면에 다른 산화물 합성에 특히 효과적이다. MnO₂는 HCS 또는 CS의 표면에 일정한 슬릿 모양의 분포를 보였고 HCS 표면에서 보다 엉성한 슬릿 모양의 MnO₂ 입자가 생성되었다. MnO₂-HCS는 20 mv s<SUP>-1</SUP>의 스캔 속도에서 초기 사이클에서 약 164.1 F g<SUP>-1</SUP>의 정전용량을 나타내었고 1000 사이클 후에는 약 141.3 F g<SUP>-1</SUP>의 정전용량을 나타내었다. 1000 사이클 기준으로 MnO₂-HCS와 MnO₂-CS는 각각 86%와 78%의 용량유지율을 나타내었다. 이것은 HCS 표면에서 엉성한 슬릿모양의 MnO₂의 성장이 전해질의 흐름 및 전해질 내의 Na⁺ 이온의 흡탈착이 보다 용이하여 나타난 결과로 생각된다. Hollow carbon spheres (HCS) and carbon spheres (CS) were prepared by a hydrothermal reaction and they were introduced as a substrate for the deposition of MnO₂ nanoparticles. The MnO₂ nanoparticles were deposited on the carbon surface by a chemical redox deposition method. After deposition, the MnO₂ nanoparticles were uniformally distributed on the carbon surface in a slit-shape, and sparse MnO₂ slits appeared on the HCS surface. The MnO₂-HCS showed an initial specific capacitance of 164.1 F g<SUP>-1</SUP> at scan rate of 20 mv s<SUP>-1</SUP>, and after 1,000 cycles, the specific capacitance was maintained to 141.3 F g<SUP>-1</SUP>. The capacity retention of MnO₂-HCS and MnO₂-CS were calculated to 86% and 78% in the cycle performance test up to 1,000 cycles, respectively. MnO₂-HCS showed a good cycle stability due to the mesoporous hollow structure which can cause a faster diffusion of the electrolyte and can easily adsorb and desorb Na+ ions on the surface of the electrode.

리튬 폴리머 전지용 정극활물질 LiFePO4 및 LiM(x)Fe(1-x)PO4의 전기화학적 특성

김은미 ( En Mei Jin ),박경희 ( Kyung Hee Park ),구할본 ( Hal Bon Gu ) 조선대학교 공학기술연구원 2009 공학기술논문지 Vol.2 No.2

Phospho-olivine LiFePO4 and LiTi0.1Fe0.9PO4 calhode materials were prepared by the solid-state reaction at the different temperature (550, 600 and 650℃). To improve conductivity carried out Ti2+ doped LiFeP04 and we studied the effect of electrochemical performance. At the different heating temperature resulted in the didn``t appearance of impurity phase which was shown by high resolution X-ray diffraction and perepared by 600℃ temperature``s discharge performance results exhibited an excellent high capacity of 140 mAh/g at the first cycle, and 139 mAh/g after 50 cycles. The Ti2+ doped LiFeP04 started 3.36 V of flat voltage on discharge curve and showed a gentle decline in the curve compared to undoped LiFeP04 without great changes of capacity. And so, we could achieve to improve electrochemical performance as reversible, cycle life. Similarly, LiFePO4 doping with Ti2+ showed the effect of dopant which is the improved discharge capacity as 140 mAh/g and good cycling performance.

염료감응 태양전지의 염료 흡착 특성 향상에 관한 연구

김은미 ( En Mei Jin ),구할본 ( Hal Bon Gu ) 조선대학교 공학기술연구원 2011 공학기술논문지 Vol.4 No.2

The acid treatment have been used for nanocrystalline TiO2 particles. It ha been observed that nitric acid treatment can enhance transparency of thin films a well as higher level of dispersion of nanoparticles. HNO3 treated surfaces has showed higher surface area and increase in hydroxy functional groups at TiO2 photoelectrode film surfaces was observed. This process has allowed to increase the conversion efficiency of solar cell which is possibly due to higher amount of dye adsorption. These process have significantly enhanced the efficiency of DSCs for developing high sensitivity. The efficiency increased upto 11 8% and this is observed at non nitric acid treatment of TiO2 photoelectrode.

수열합성한 TiO2을 이용한 염료감응형 태양전지의 전기화학적 특성

김은미 ( En Mei Jin ),왕만림 ( Wan Lin Wang ),구할본 ( Hal Bon Gu ) 조선대학교 공학기술연구원 2013 공학기술논문지 Vol.6 No.1

In this study, the TiO2 was prepared by hydrothermal reactions; and 0.5 M, 1.0 M and 2.0 M TTIP were added. The different contents of TTIP added TiO2 are studied by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), and photocurrent density-voltage test. The photovoltaic properties under illumination with AM 1.5 simulated under sunlight. In the results, the XRD patterns index to single-phase material having an anatage structure and the particle size of 1.0 M TTIP added TiO2 is 7.61 nm. Using the 1.0 M TTIP added TiO2 demonstrates a higher solar conversion efficiency than the other samples. We got 114% and 131% enhanced power conversion efficiency when the optimal content of TTIP.