Fabrication of carbon nanofiber electrodes using poly(acrylonitrile‑co‑vinylimidazole) and their energy storage performance

Kyung‑Hye Jung,So Jeong Kim,Ye Ji Son,John P. Ferraris 한국탄소학회 2019 Carbon Letters Vol.29 No.2

For electrodes in electrochemical double-layer capacitors, carbon nanofibers (CNFs) were prepared by thermal treatment of precursor polymer nanofibers, fabricated by electrospinning. Poly(acrylonitrile-co-vinylimidazole) (PAV) was employed as a precursor polymer of carbon nanofibers due to the effective cyclization of PAV polymer chains during thermal treatment compared to a typical precursor, polyacrylonitrile (PAN). PAV solutions with different comonomer compositions were prepared and electrospun to produce precursor nanofibers. Surface images obtained from scanning electron microscopy showed that their nanofibrous structure was well preserved after carbonization. It was also confirmed that electrospun PAV nanofibers were successfully converted to carbon nanofibers after the carbonization step by Raman spectroscopy. Carbon nanofiber electrodes derived from PAV showed higher specific capacitances and energy/power densities than those from PAN, which was tested by coin-type cells. It was also shown that PAV with an acrylonitrile/vinylimidazole composition of 83:17 is most promising for the carbon nanofiber precursor exhibiting a specific capacitance of 114 F/g. Their energy and power density are 70.1 Wh/kg at 1 A/g and 9.5 W/kg at 6 A/g, respectively. In addition, pouch cells were assembled to load the higher amount of electrode materials in the cells, and a box-like cyclic voltammetry was obtained with high capacitances.

팽이버섯의 저장성에 미치는 광석분말을 함유한 한지의 포장효과

이예경,신경옥,정유경,박범호,김순동 동아시아식생활학회 2004 동아시아식생활학회지 Vol.14 No.5

The effect of polyethylene film(PE) packaging of golden mushroom wrapped with Korean paper containing 20% mica powder on the changes in weight, color, texture, PPO activity, number of total microbe(TM) and sensory quality during storage at 10℃ were investigated. The experiments were divided to 3 groups(control; only PE packaging, KP; PE packaging wrapped with Korean paper up and down of the sample, KPM; PE packaging with Korean paper containing 20% mica powder up and down of the sample). The weight of the mushroom in the KPM was the lowest until 9 days-storage, but the weight was the highest at 15 days-storage, showing 12.5% higher against the initial weight. L^(*) values of the mushrooms in the control and KP treatment were decreased, but the value in the KPM treatment was maintained as the same of the initial value during storage. The increasing rate of a^(*) and b^(*) values in the all plots during storage was the lowest in KPM and in order of KPM<KP<control. The activity of PPO and number of TM in the KPM treatment were maintained the lowest, but hardness and gumminess were maintained the highest during storage. Appearance of the mushroom stored for 15 days was the best, the degree of browning and softening were the lowest in the KPM. Off-flavor was lower in all plots, but the scores were the lowest in KPM. But further study on the fruit body was grown in the KPM at after-period of storage was required.

Sol-gel법으로 제조한 SrZrO₃ 피막의 접착강도 특성

예경환,송요승 한국항공대학교 항공우주산업기술연구소 2003 航空宇宙産業技術硏究所 硏究誌 Vol.13 No.-

SrZrO₃ resistive oxide barriers on Ag sheathed Bi2223 tapes were prepared by the sol-gel and dip coating method to reduce AC coupling loss. The performance of the dip-coated SrZrO₃, thin films was evaluated in terms of bond strength by varying Sr/Zr mol ratio and amount of organic vehicle (ethyl cellulose and a-terpineol) additives. Although bond strength of the coatings increased as the Sr/Zr ratio decreased and the amount of organic vehicle rose, the effect of organic vehicle addition was more pronounced, suggesting that adherence of the SrZrO₃ films on Bi2223 tapes was governed primarily by the amount of organic vehicle additive.

가로환경 시설물로서의 버스 정거장 사례분석 : 서울시 디자인거리 중 5개구를 중심으로

예미진;남경숙 한양대학교 2008 韓國 生活 科學 硏究 Vol.28 No.1

In our society the space and facilities for the public have rised in the amount during the achievement of the rapid growth and the industrialization. But the policy-oriented development focusing on the quantitative and the modernization have not obtained the ideal goal and exemplary results through supply with the facilities. Recent years the government of the republic of Korea giving priority to 'design' has studied the model cases in the design for the public in the advanced countries like the United States of America ,the Europe and Japan. Also many kind of promotion policies keeping the accent on the design like 'The creative city of UNESCO' and '2010 WDC Seoul' have helped the policy for globalization and they are accelerating to full-blown study and operation. In this study though analysis the present condition of 5 bus stations in Seoul and the model cases in the design for the public in the advansed countries, the source materials are proposed.

퇴행성관절염 환자의 보행시 지면 반력 분석

이경옥,김미예 한국특수체육학회 2003 한국특수체육학회지 Vol.11 No.3

The purpose of this study is to analyze ground reaction force of walking for elderly women with degenerative osteoarthritis. The force platform (Kistler Type 9281CA, sampling frequency 1000HZ) was used to measure ground reaction force. Dependent variables for this study included both vertical and anterior/posterior ground reaction force components of walking. The paired t test was used to analyze the variables of the gait cycle for both the left and right side. The passive force peaks for elderly women with degenerative osteoarthritis had a greater magnitude and were greater in number than those of the control group. For the elderly group, active force peaks had a higher magnitude and were more frequent as well. The pattern of active force for the control group was symmetrical, while the pattern for the elderly group was asymmetrical. Compared to the control group, the stance time for elderly women was less. The total integral for the elderly group was less than that of the normal group. Braking time was less for elderly women in comparison to the control group. There were differences in the right and left leg for total impulse, braking time, and the impulse of braking force as well.

소나무 재생버섯(Fomitopsis pinicola Jeseng) 다당류의 추출 특성

장경호,신진기,이명예,이상일,김정숙,오승희,김순동 동아시아식생활학회 2005 동아시아식생활학회지 Vol.15 No.1

This study was conducted to investigate the extraction characteristics of the polysaccharide from Jeseng mushroom (Fomitopsis pinicola Jeseng). Yields of the polysaccharide extracted from powdered mushroom by autoclaving(120, 30 min) with water at different pH and salt concentration were 8.2~9.2% in pH 5~11, 4.7~5.5% in 1.5% salt solution, respectively. The yield by the 0.05~1.0 N KOH-extraction was ranged 3.45~13.20%, while that by HAS-extraction(homogenizing after KOH swelling) using 1~2.5 N KOH 73.6~78.4%. Content of carbohydrate, protein, lipid and ash of the crude polysaccharide extracted from fruits body and its cultured mycelium by method of water extraction, KOH extraction(0.005~1N) and HAS-extraction were ranged 86.5~92.6%, 2.3~13.1%, 0.1~4.2% and 0.1~1.7%, respectively. The polysaccharide were composed of 62.0~77.8 g/g of pentose, 138.0~187.8 g/g of hexose and 21.2~117.3 ㎎/g of protein. From these results, the polysaccharide extracted was supposed to be a protein-bound polysaccharide.

온천수가 반죽의 발효와 품질에 미치는 영향

이예경,김순동 동아시아식생활학회 2003 동아시아식생활학회지 Vol.13 No.1

The dough fermentation and the quality of bread prepared with different kinds of water such as distilled water, tap water and diluted hot spring water(SW) from Gyungsan Sipan hot spring were investigated. Content of total soluble solid in the hot spring waterwas 8,765 ppm and contents of Na, Ca, Mg and K as major elements was 2,296, 287, 65 and 8 ppm, respectively. Content of Fe, Cu, Co, F, Zn, Al, S, Mo, Se and Si as minor elements was in the range of 0.002~5.2 ppm. The pH(6.95~7.68) of the dough prepared with diluted hot spring water(Ⅰ, 55 times; Ⅱ, 4 times; Ⅲ, 2 times) was higher than that of distilled water. The dough volume after the 1st fermentation was expecially lower in the Ⅲ, but the volume of the dough prepared with Ⅲ adjusted pH to 5.5 was higher than that of the control. The hardness and the strength were higher than those of the control, but the scores were lower than those of the control in case of pH adjustment(pH 5.5). The cohesiveness was also lower than that of the control in the bread with diluted hot spring water. Softness and stickiness of the bread(Ⅲ) were higher than those of the control. But overall acceptability was the highest in the Ⅱ.

청국장 물 추출물이 반죽의 발효와 빵의 품질 특성에 미치는 영향

이예경,이명예,김미정,김순동 동아시아식생활학회 2004 동아시아식생활학회지 Vol.14 No.5

The effect of water extracts of Chungkukjang(WEC: 10%, w/v), which was prepared using Bacillus subtilis isolated from Korean traditional Chungkukjang, on the pH, acidity and volume of the dough, and loaf volume index(LVI), color, texture, retrogradation degree, microscopic observation and sensory quality of the bread were investigated. Experimental plots were divided to 3 groups(Control; without WEC, Ⅰ; added 2.5% WEC against total amount of water, Ⅱ; added 5.0% WEC against total amount of water). There were no significant difference in pH and acidity among each experimental groups. Dough volume were higher but LVI were lower in the Ⅰ- and Ⅱ-bread than those of control group. L^(*) values of the top crust and internal tissue in the Ⅰ-and Ⅱ-bread were lower than those of control group. The higher addition amounts had the lower L^(*) values. Hardness, strength, gumminess and brittleness were higher, but cohesiveness and springiness were lower in the WEC-breads than those of control. In the results of microscopic observation, there were scarce of the bigger starch granules and a sparse structure, while there were smaller starch granules in the WEC-bread. The scores of crispy taste of the WEC-bread were lower than those of the control group, but there were no significant difference in tenderness, odor, savory taste and overall acceptability between the control and the Ⅰ-bread. The retrogradation rate of the bread stored for 3 days at 25t was 45.09% in control, 17.92% in Ⅰ-bread, and 12.45% in Ⅱ-bread, respectively.

일 지역 농업인의 근력강화운동이 정신사회 및 신체적 건강수준에 미치는 영향

정민예,양노열,유인규,고상백,이경숙,김경란,김효철 大韓産業醫學會 2008 대한직업환경의학회지 Vol.20 No.4

목적 농업인을 대상으로 근골격계질환의 예방과 관리를 위한 근력강화운동을 실시하여 심리상태와 신체능력에 미치는 효과를 밝힘으로써 농작업과 관련된 향후 치료프로그램의 기초자료를 제공하고자 하였다 방법 규칙적인 운동프로그램의 참여 경험이 없는 농작업 종사자 28명을 대상으로 8주간 주 3회 근력강화운동을 실시하여 4주 이상 규칙적으로 참여한 대상자의 정신사회적 수준(자아존중감 사회심리적 스트레스) 신체적 수준(장악력 민첩성 동 정적 균형능력 근지구력) 요통 수준의 변화를 측정하였다 결과 근력강화운동에 참여한 대상자들의 자아존중감은 운동전에 비하여 유의하게 향상되었고 사회 심리적 스트레스는 유의하게 감소하였다 장악력 민첩성 동 정적균형능력은 운동 후 모두 유의하게 향상되었으며 요통 수준 또한 유의하게 감소하였다 결론 농업인에게 근력강화운동의 적용은 심리적인 안정을 주고 신체능력을 향상시켜 근골격계질환을 예방하고 관리하는데 적합한 치료프로그램으로 사용될 수 있으며 요통 수준을 감소시키는데 유용한 프로그램이었다. Objectives To evaluate both the psychosocial and physical effects of muscle strengthening exercise on farmers and in so doing evaluate their effect on musculoskeletal disorders in farmers. Methods 28 subjects participated in our muscle strengthening exercise program. Mean age of subjects was 63±13 years. The exercise program was performed 3 times a week during the 8 week studys period Before and after training various measurements were made self esteem scale (SES), psychosocial well being index short form (PWI SF), static and dynamic balance ability grip strength arm curl, time up and go (TUG), functional reach, and oswestry disability index. Results The muscle strengthening exercise program increased the self esteem grip strength and static and dynamic balance of subjects, while psychosocial stress and low back pain levels were decreased significantly (P<0.05) Conclusions The muscle strengthening exercise improved psychosocial and physical status of test subjects. Thus exercise may be an effective strategy for enhancing the psychosocial and physical health of farmers.

Calcium Acetate의 첨가가 반죽의 발효와 빵의 품질특성에 미치는 영향

이예경,이명예,김순동 동아시아식생활학회 2003 동아시아식생활학회지 Vol.13 No.6

This study was conducted to investigate the quality characteristic of bread added with 0, 2, 4 and 8% liquid calcium acetate(LCA-breads) to the dough prepared with brown rice, vinegar and ash of black snail replacing wheat flour. The pH of the dough was 5.38 in control and 5.39~5.42 in the LCA-breads, which showed that the higher the content of LCA, the higher the pH. There was no big difference of the baking loss between control (10.73%) and LCA-breads(10.11~10.81%). The loaf volume index was 7.12 in the control, 7.18 in the 2% LCA-bread, while the index was 6.22 in the 4% LCA-bread, 5.80 in the 8% LCA-bread. Calcium content was 16 ㎎% in the control, 30, 60 and 120 ㎎% in 2, 4 and 8% LCA-bread, respectively. The hardness, gumminess and brittleness of LCA-breads were higher, while springiness and cohesiveness were lower than that of the control. In the LCA-breads, L^(*) values were lower and b^(*) value was higher than those of the control, while there were no significant difference in a^(*) values. Increasing the LCA, air cells were bigger and irregular, and starch matrix was unstable. There were no significant difference in sour and bitter taste. The scores of stickiness of the 2~4% LCA-breads were similar to that of the control and higher in the 8% LCA-bread. The scores of the flavor and overall taste in the LCA-breads were similar to the control, while the values were lower in the 4~8% LCA-breads. The shelf-life evaluated by the number of moldy spots was not different between the control and 2% LCA-bread, while it was extended two times in 4% and three times in the 8% LCA-bread.