The recycling of solid waste materials to fabricate carbon-based electrode materials is of great interest for low-cost green supercapacitors. In this study, porous carbon foam (PCF) was prepared from waste floral foam (WFF) as an electrode material for supercapacitors. WFF was directly carbonized at various temperatures of 600, 800, and 1,000 oC under an inert atmosphere. The WFF-derived PCF (C-WFF) was found to have a specific surface area of 458.99 m2/g with multi-modal pore structures. The supercapacitive behavior of the prepared C-WFF was evaluated using a three-electrode system in a 6 M KOH aqueous electrolyte. As a result, the prepared C-WFF as an active material showed a high specific capacitance of 206 F/g at 1 A/g, a rate capability of 36.4 % at 20 A/g, a specific power density of 2,500 W/kg at an energy density of 2.68 Wh/kg, and a cycle stability of 99.96 % at 20 A/g after 10,000 cycles. These results indicate that the C-WFF prepared from WFF could be a promising candidate as an electrode material for high-performance green supercapacitors.

In this study, N/S co-doped carbon felt (N/S-CF) was prepared and characterized as an electrode material for electric double-layer capacitors (EDLCs). A commercial carbon felt (CF) was immersed in an aqueous solution of thiourea and then thermally treated at 800 oC under an inert atmosphere. The prepared N/S-CF showed a large specific surface area with hierarchical pore structures. The electrochemical performance of the N/S-CF-based electrode was evaluated using both 3- electrode and 2-electrode systems. In the 3-electrode system, the N/S-CF-based electrode showed a good specific capacitance of 177 F/g at 1 A/g and a good rate capability of 41% at 20 A/g. In the 2-electrode system (symmetric capacitor), the freestanding N/S-CF-based electrode showed a specific capacitance of 275 mF/cm2 at 2 mA/cm2, a rate capability of 62.5 % at 100 mA/cm2, a specific power density of ~ 25,000 mW/cm2 at an energy density of 23.9 mWh/cm2, and a cycling stability of ~ 100 % at 100 mA/cm2 after 20,000 cycles. These results indicate the N/S co-doped carbon felts can be a promising candidate as a new electrode material in a symmetric capacitor.

Hierarchically porous carbon materials with high nitrogen functionalities are extensively studied as highperformance supercapacitor electrode materials. In this study, nitrogen-doped porous carbon textile (N-PCT) with hierarchical pore structures is prepared as an electrode material for supercapacitors from a waste cotton T-shirt (WCT). Porous carbon textile (PCT) is first prepared from WCT by two-step heat treatment of stabilization and carbonization. The PCT is then nitrogendoped with urea at various concentrations. The obtained N-PCT is found to have multi-modal pore structures with a high specific surface area of 1,299 m2 g−1 and large total pore volume of 1.01 cm3 g−1. The N-PCT-based electrode shows excellent electrochemical performance in a 3-electrode system, such as a specific capacitance of 235 F g−1 at 1 A g−1, excellent cycling stability of 100 % at 5 A g−1 after 1,000 cycles, and a power density of 2,500 W kg−1 at an energy density of 3.593 Wh kg−1. Thus, the prepared N-PCT can be used as an electrode material for supercapacitors.

Porous carbons have been widely used as electrode material for supercapacitors. However, commercial porous carbons, such as activated carbons, have low electrochemical performance. Nitrogen-doping is one of the most promising strategies to improve electrochemical performance of porous carbons. In this study, nitrogen self-doped porous carbon (NPC) is prepared from melamine foam by carbonization to improve the supercapacitive performance. The prepared NPC is characterized in terms of the chemical structures and elements, morphology, pore structures, and electrochemical performance. The results of the N2 physisorption measurement, X-ray diffraction, and Raman analyses reveal that the prepared NPC has bimodal pore structures and pseudo-graphite structures with nitrogen functionality. The NPC-based electrode exhibits a gravimetric capacitance of 153 F g−1 at 1 A g−1, a rate capability of 73.2 % at 10 A g−1, and an outstanding cycling ability of 97.85% after 10,000 cycles at 10 A g−1. Thus, the NPC prepared in this study can be applied as electrode material for high-performance supercapacitors.

The purpose of the present study is to analyze needs of graduate students for English education for their academic study. Online survey was administered to all the graduate students in a university located in Seoul, Korea, and a total of 1,241 students participated in this study. The participants varied in majors including humanities and social sciences, natural sciences, engineering, medicine, and so forth. Crosstab analyses were performed in order to analyze the survey data, followed by subordinate analyses by the participants’ majors. Results indicated that most students perceived the great importance of English for their study, and ‘listening’ and ‘speaking’ were found to be the most difficult areas when students take English-medium graduate courses. In addition, although the frequency of scholarly activities varied by majors, most of the students expressed difficulties in writing research papers and making presentations. Based on the results, the present study suggests that English education programs be expanded and opened in order to meet the different needs by the students’ academic majors.

양이온 계면활성제는 살균력을 가지고 있으며 이를 개발하기 위한 연구는 다양한 산업분야에 서 계속 진행되고 있다. 단순히 우수한 성능을 가질 뿐만 아니라 생분해성이 우수한 계면활성제를 개발 하기 위한 연구는 증가되고 있다. 본 연구에서는 Michael addition 반응을 통하여 ester-type의 양이온 계면활성제를 합성하였다. 실온에서 촉매없이 alkyl acrylate와 1차 아민을 가지는 화합물을 합성한 뒤 dimethyl sulfate 로 4차화시킨다. 2개의 소수기와 한 개의 친수기를 갖는 HQ21과 2개의 소수기와 2개 의 친수기를 갖는 HQ22를 합성하였다. 이들 합성화합물은 1H-NMR, HR-MS 와 FT-IR로 구조를 확인하였으며 생분해성을 측정하였다.

The main goal of this study is to examine elementary school students’ four-nights-and-five-days experience at an English village in Seoul, focusing on what English learning experiences they had and what kind of changes had been made in their attitudes towards learning English. Pre- and post-surveys were conducted to examine their learning experiences in the village and the changes in their attitudes toward learning English. About 350 students participated in the pre- and post-surveys and additional ten students also participated in an interview with the researcher to draw more detailed information about their experiences in the English village. Descriptive statistics and paired samples t-tests were conducted to answer the main research questions. The results revealed that despite the short term of residence at the English village, the students seemed to have had relatively active engagement in learning both listening and speaking skills, but not as much in learning reading and writing skills. Also, although the village could possibly provide students with rich opportunities to have an active engagement and interaction with peers and English speaking teachers, it seemed that there existed some limitations in having such experiences inside and outside of the classrooms. Finally, students showed some changes in their attitudes or strategies toward learning English after the short term of residence, saying that they wanted to have more diverse engagement with English, such as 'having a conversation with foreigners on the Internet’, ‘keeping a journal in English,’ ‘having a conversation in English with other peers,’ and so on.

The purpose of this study is to examine the function and spread of English in Korean academic society by investigating the use of English in writing dissertations. To this end, this study selected one of the universities in Korea and attempted to identify to what extent English has been used in master"s and doctoral dissertations for the last 12 years. The results show that the use of English in writing both master"s and doctoral dissertations has increased gradually and there exists a discrepancy among the fields of study. The results also reveal that a number of dissertations in the fields of natural science, engineering and medical science have been written in English recently. The comparison of the results of this study and some related analyses in European universities indicates a similar trend of English use in academic fields. Understanding the current use of English in Koreanacademic society can lead to a better understanding of the role and function of English in Korea as a whole.

This paper reports the current situation of English and English education in North Korea. Two approaches are taken to achieve the goal: One is to examine social attitudes and government approaches to English education. Interviews with defectors from North Korea, newspaper reports and other related literature are used. The other is to analyze middle school English textbooks and research articles to reveal the current practice of English language teaching at schools. The results show that North Korean government and people are interested in learning and teaching English and they take various measures to improve English learning to meet national or individual goals. English seems to be considered as a way of improving their economic situations and finding a better opportunity for many North Korean people. However, English education in North Korea is still limited in terms of resources including learning materials and native teachers of English. Also academic research and practices in English education are still heavily influenced by Kim Ilsung and Kim Jungil’s words so that scientific investigations are limited. It is an impending issue to narrow a gap in English education between South and North Koreas to overcome difficulties encountered in the future.

The main goal of this study is to review the role of the age factor in foreign language education and to discuss its implications in Korean English education. ‘The younger, the better', under the critical period hypothesis, has recently played a critical role in the introduction of English language education to young children in Korea and the public and the govemment seem to be highly dependent upon the hypothesis when they decide children’s English education. For example, the English education program in Korean elementary schools is an offspring of this theory. This study, however, casts a doubt on the effect of age on English education by reviewing theoretical and experimental studies focusing on whether age or the critical period hypothesis is a meaningful factor to validate the early exposure of foreign language education and its following success. Findings from foreign language education in US, French immersion programs in Canada and other foreign countries and adult second language leaming and studies dealing with the critical period hypothesis were critically reviewed to provide evidences to such argument that age is not a primary factor to determine early English education in Korea. On the contrary, time or the amount of exposure to the English language should be a more critical factor in a context where a very limited exposure to the target language is only possible. A list of generalizations and implications are also provided.

본 연구는 인천 게임산업단지 조성을 통한 경제적 파급효과를 분석하는데 있다. 게임산업은 문화콘텐츠 산업으로서 큰 잠재가능성을 가지고 있어, 발전에 대한 당위성이 높다는 다양한 의견을 가지고 있음에도 불구하고, 이에 대한 경제적 파급효과를 분석한 사례는 거의 없는 실정이었다. 따라서 본 연구는 이를 선험적으로 분석하는 측면에서 연구에 대한 의의를 가질 수 있다. 이의 분석을 위해 인천경제자유구역내에 게임산업단지를 설립하는 경우를 가정하고 건설부문, 게임관련 제조업 및 게임관련 서비스업을 토대로 지역산업연관분석을 실시하였다. 본 연구의 결과를 통해 게임산업이 지역 및 국가에 미치는 중요성을 직접적으로 파악할 수 있으며, 향후 이와 관련한 연구의 방향에 큰 영향을 미칠 수 있을 것이다.