Enhanced H₂S sensing performance of TiO₂-decorated α-Fe₂O₃ nanorod sensors

Kheel, Hyejoon,Sun, Gun-Joo,Lee, Jae Kyung,Lee, Sangmin,Dwivedi, Ram Prakash,Lee, Chongmu Elsevier 2016 Ceramics international Vol.42 No.16

<P><B>Abstract</B></P> <P>Pristine and TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorods were synthesized via thermal oxidation of Fe thin foils, followed by the solvothermal treatment with titanium tetra isopropoxide (TTIP) and NaOH for TiO<SUB>2</SUB> nanoparticle-decoration. Subsequently, gas sensors were fabricated by connecting the nanorods with metal conductors. The structure and morphology of the pristine and TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorods were examined via X-ray diffraction and scanning electron microscopy, respectively. The gas sensing properties of the pristine and TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensors with regard to H<SUB>2</SUB>S gas were examined. The TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor showed a stronger response to H<SUB>2</SUB>S than the pristine Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor. The responses of the pristine and TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensors were 2.6 and 7.4, respectively, when tested with 200ppm of H<SUB>2</SUB>S at 300°C. The TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor also showed a faster response and recovery than the sensor made from pristine Fe<SUB>2</SUB>O<SUB>3</SUB> nanorods. Both sensors showed selectivity for H<SUB>2</SUB>S over NO<SUB>2</SUB>, SO<SUB>2</SUB>, NH<SUB>3</SUB>, and CO. The enhanced sensing performance of the TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor compared to that of the pristine Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor might be due to enhanced modulation of the conduction channel width, the decorated nanorods’ increased surface-to-volume ratios and the creation of preferential adsorption sites via TiO<SUB>2</SUB> nanoparticle decoration. The dominant sensing mechanism in the TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor is discussed in detail.</P>

Hydrogen Gas Detection of Nb₂O₅ Nanoparticle-Decorated CuO Nanorod Sensors

Kheel, Hyejoon,Sun, Gun-Joo,Lee, Jae Kyung,Mirzaei, Ali,Choi, Seungbok,Lee, Chongmu Hanrimwon Publishing Co. 2017 METALS AND MATERIALS International Vol.13 No.4

School Based Club Sport Experience from Group Developmental Perspective

( Sungmin Kheel ),( Youngmi Kim ),( Kyungsook Kim ) 한국체육학회 2016 국제스포츠과학 학술대회 Vol.2016 No.1

Background: Previous studies on group development tried to understand the nature and characteristics of changes in small groups over time. Thus, school sport clubs can be a good candidate for group developmental study considering its organizational nature. To date, numerous research in school sport clubs focused on the satisfaction, benefits, or social/psychological factors related to its participation. However, the research on personal development in accordance with group development are yet to be investigated. Purpose: This study examined the students’ experience on school sport clubs from a group developmental perspective. It aimed to identify the aspects that can constitute personal development from experience acquired over time in team-sport settings. Methods: Essays submitted for a nation-wide contest with a theme on school sport club experience were collected from K1 to K12 students (N=297). Among the submissions, only the prize-wining essays written by middle school students were selected (n=8) because paragraph construction and writing quality were fit for the study. As a case study, the paradigmatic reasoning approach was undertaken. The trustworthiness of the research was established by member’s check and peer debriefing. Results: According to Tuckman (1965), growth of a team requires going through a series of developmental stages to grow, to face up to challenges, to tackle problems, to find solutions, to plan work, and to deliver results. But, according to our findings, only four essays out of eight showed the traditional pattern of the five stages (forming, storming, norming, performing, adjourning) of group development. Case #2, #3, #5 showed all five stages. Case #3 experienced severe storming stage accompanied with disagreements and personality clashes among peers. Case #4 skipped the storming stage and directly reached performing stage in which group members focus on achieving common goals, often reaching an unexpectedly high level of success. Case #1 did not mention any group developmental experience but rather focused on personal growth. This case was different from other cases in that participant played a role as referee who intended to alienate himself from players for an impartial call of the game. Case #5 and #7 emphasized norming stage in which disagreements and personality clashes could be resolved and the common goal was shared. Case #8 described mostly about the adjourning stage. In this case, when the game seasons ended, the team was dismissed. Conclusion: Prior experiences in school sport clubs made participants more comfortable and relaxed during the forming stage. Duration or intensity of storming stages was influenced from the history of the team and its members. The newer club experienced more severe storming stage. After the storming, stages of norming, performing, and adjourning occurred subsequently. But depending on the situation of the group, some stages were skipped. In sum, students’ experiences from school sport clubs varied depending on their group developmental stages. However, due to the sample size and data analysis procedure, Caution is required in generalizing findings. Further investigation to extend the group development theory in a school sport club setting is necessary.

Ethanol sensing properties of MoO₃-core/ZnO-shell nanorod sensors

Hyejoon KHEEL,Gun-Joo SUN,Soong Keun HYUN,Hyoun Woo KIM,Chongmu LEE 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

장학사의 관점에서 바라 본 학교스포츠클럽 운영현황의 문제점 및 개선방안

길성민(Kheel, Sung-Min),홍은아(Hong, Eun-Ah),김영미(Kim, Young-Mi) 한국체육과학회 2017 한국체육과학회지 Vol.26 No.6

The aim of the study was to estimate the current status and level of local cooperation in supporting the school sports club. In Korea, most of the local cooperative efforts with its public school system proceed under the administrative aid of the superintendent. Therefore, our research population was set to the superintendent in charge of school sports clubs at the Education Department of local governments (17 provincial and 176 municipal levels). Using the online survey method, 196 surveys were collected and 130 were used for final data analysis excluding those that were incomplete. Via descriptive and correlation analysis, the results indicated that 1) teacher volunteer groups were the most cooperative group followed by school, local sport council; 2) a high amount of workload at the teacher volunteer group was the greatest barrier to establishing a local cooperative system; 3) local cooperation systems work best in the area of facility provision but not in away game traveling and lodging; 4) some of the most urgent areas where local cooperation is needed are manpower to operate the games, more staff for administrative work, and sponsoring of game supplies. Drawn from the results, most school sport clubs depend on a supportive system of teacher volunteer groups without which will induce teacher burnout. The investigators suggest that developing the diverse cooperation groups in new areas such as parents support group, medical assistance from local hospitals and clinics, and private sports clubs will be a strategic approach to a prosperous school sports club.

EFL 학생들을 위한 효율적인 5분 스피치 활용

길형석(Hyungsuk Kheel),성지희(Jeehee Sung) 학습자중심교과교육학회 2005 학습자중심교과교육연구 Vol.5 No.2

글로벌 시대를 성공적으로 살아가기 위해서는 효율적인 스피치를 통하여 자신의 생각과 의견을 전달하는 능력이 필요하다. 특히 교실 밖에서는 영어를 접할 기회가 부족한 EFL 상황에 놓여있는 학습자들의 요구와 시대적 요구를 동시에 만족시켜 줄효율적인 스피치 교육에 대한 연구가 필요하게 된 것이다. 본 연구는 EFL학습자들을 위한 효율적인 5분 스피치 교육의 발전방향을 모색해 보기 위한 연구이다. 이를 위하여 영어교육의 목적인 의사소통능력을 배양하기 위한 5분 스피치의 개념을 살펴 보고 의사소통적․교육학적․심리학적으로 논의한다. 효율적인 5분 스피치가 되기 위해서는 외국어로서의 영어교육의 본질적인 목적과 비판적․창의적 사고능력과 심리적인 말하기불안감까지 깊이 이해하는 것이 필요하 다. 또한 효율적인 5분 스피치 교육은 학습자들에게 효율적으로 말을 하고 능률적으로 들으며 창의적으로 사고하고 청중에게 자신의 메시지를 전달하는 데에 필요한 기술과 자신감을 배양할 수 있는 충분한 기회를 제공해 주는 교육을 말한다. 5분 스피치교육에서 학습자들이 어떠한 학습의 효과를 누리는 지에 대한 심도있는 분석을 위해서 본 연구에서는 질적 연구의 방법을 택하였다. 11명의 학습자들이 자신 에게 의미있는 주제를 정하고 브레인 스토밍을 하고 주제를 좁혀가고 아이디어를 공유하였는데, 언어적인 요소 뿐만 아니라 비언어적인 요소까지 학습하고 연습하여 실제로 5분 스피치를 청중들 앞에서 연설한 후, 5분 스피치에 대한 의견을 나타내었다. 참여자들의 5분 스피치 대본과 각 스피치에 대한 반응과 전반적인 평가나 느낀 점 등의 양적 자료를 수집하여 실제로 학습자들이 어떠한 의사소통적․교육학적․심리학적 효과를 얻었는 지에 대해 분석하였다. 결론과 분석이 의사소통적․교육학적․심리 학적 관점에서 논의되었으며 마지막으로 효율적인 5분 스피치를 위한 활동이 제안되 었다. The purpose of this study is to suggest effective five-minute speech activities for students of English as a foreign language, focusing on the communicative, educational, and psychological aspects of language teaching and learning. Preparing and designing an effective five-minute speech program requires a comprehensive understanding of the aim of teaching English as a foreign language and the importance of critical thinking. To design an effective five-minute speech program, teachers also consider the psychological aspect of speech. Also, a five-minute speech program should provide students with enough opportunity to speak effectively, listen efficiently, think critically, enhance confidence in their messages to the audience. The qualitative research method is employed to provide an in-depth analysis of how students can benefit from a five-minute speech program. Students wrote about topics which they had chosen on the basis of personal interest and relevance in order to prepare for their 5 minute speech after they brainstormed about their topics and shared their ideas. They learned the importance of nonverbal communications as well as verbal communications in English. After they delivered their 5 minute speech, they talked about things that were beneficial to them. The finding are discussed in terms of linguistic, educational, and psychological aspects. The results of this study are as follows: first, the application of the 5 minute speech program to EFL students are characterized as the effective program which provides students with enough opportunity to develop their confidence in delivering their message, enhance their communicative competence, and take a positive and humanistic view of life. In sum, students can benefit from a well designed five-minute program. Suggestions for effective five-minute activities are also made for ways to use five-minute speech program in the EFL classroom.

직업교육과 인간자본

길형석(Hyung Suk Kheel) 한국직업교육학회 1986 職業 敎育 硏究 Vol.5 No.1

여성의 진로교육에 관한 연구

길형석(Hyung Suk Kheel) 한국직업교육학회 1989 職業 敎育 硏究 Vol.8 No.1

생애직업지도의 한국적 과제 - 각국의 진로개발교육을 중심으로 -

길형석(Hyung Suk Kheel) 한국직업교육학회 1982 職業 敎育 硏究 Vol.1 No.1

교육사회학의 연구동향과 직업교육

길형석(Hyung Suk Kheel) 한국직업교육학회 1984 職業 敎育 硏究 Vol.3 No.1