• Title/Summary/Keyword: Oh Gyu-won

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Preparation and Characterization of $Li_4Ti_5O_{12}$ using Sol-Gel Method for Lithium Secondary Battery (Sol-Gel 방법을 이용한 리튬이차전지용 $Li_4Ti_5O_{12}$의 제조 및 특성)

  • Oh, Mi-Hyun;Kim, Han-Joo;Kim, Gyu-Sik;Kim, Young-Jae;Son, Won-Keun;Lim, Kee-Joe;Park, Soo-Gil
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.1989-1991
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    • 2005
  • Lithium titanium oxide as anode material for energy storage prepared by novel synthesis method. $Li_4Ti_5O_{12}$ based spinel-framework structures are of great interest material for lithium-ion batteries. We describe here $Li_4Ti_5O_{12}$ a zero-strain insertion material was prepared by novel sol-gel method and by high energy ball milling (HEBM) of precursor to from nanocrystalline phases. According to the X-ray diffraction and scanning electron microscopy analysis, uniformly distributed $Li_4Ti_5O_{12}$ particles with grain sizes of 100nm were synthesized. Lithium cells, consisting of $Li_4Ti_5O_{12}$ anode and lithium cathode showed the 173 mAh/g in the range of $1.0{\sim}3.0V$. Furthermore, the crystalline structure of $Li_4Ti_5O_{12}$ didn't transfer during the lithium intercalation and deintercalation process.

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The Necessity Analysis of Development Waterproofing Materials and Methods of Construction Technologies for Green Roofs (옥상녹화시스템의 방수재료 및 공법개발에 관한 필요성 분석)

  • Kwon, Shi-Won;Jo, Il-Gyu;Bae, Kee-Sun;Oh, Sang-Keun
    • Journal of the Korea Institute of Building Construction
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    • v.4 no.1
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    • pp.111-118
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    • 2004
  • The need for this study must be considerable. as being activate of green roofs research that the organization and construction obtain access to more development technologies. Nevertheless, the green roofs system has begun to apply since 1980's, the green roofs technology was restricted to develop without verification of technologies such as a load or water leakage. There is a limit as urethane waterproofing to almost domestic waterproofing materials and methods of construction for general green roofs. The introduction of materials and methods of construction which are appropriated to property of green roofs could be a decisive factor in a long-range durability and economical maintenance cost, moreover, it support to variety construction system and organization. This present paper describes a necessity of waterproofing and root barrier system is one of the sub-organization based on green roofs construction. which have enormously large impact on the durability.

A Study on Update for Part Area of Background Image in Real-Time (실시간 배경영상의 부분영역 갱신에 관한 연구)

  • Lee, Kwang-Hyoung;Kim, Yong-Gyun;Choi, Nae-Won;Jee, Jeong-Gyu;Oh, Hae-Seok
    • Proceedings of the Korea Information Processing Society Conference
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    • 2002.11a
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    • pp.715-718
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    • 2002
  • 실시간 동영상에서 객체의 추적은 배경영상에서 움직이는 객체를 추출하고 추출된 객체의 이동을 추적하는 것으로 컴퓨터 비전 및 여러 실용적 응용 분야에서 관심을 가지는 주제중 하나이다. 본 논문에서는 실시간 객체의 추적에서 배경영상과 입력영상의 차영상을 이용하는 방법의 전 처리로 시간의 흐름에 따라 변화되는 배경영상의 잡음을 최소화하기 위하여 입력영상의 일부분을 배경영상으로 대체함으로 최신의 배경영상을 유지 할 수 있는 방법을 제안하고자 한다. 실시간 동영상의 객체추적은 배경영상과 입력영상의 차를 이용하는데 최초의 배경영상은 시간의 흐름에 의해 빛의 양이나 주위환경에 의해 많은 변화를 가져오게 된다. 또한 실시간으로 처리해야 하는 시간성으로 인해 최신의 배경영상을 획득하는데 많은 처리시간을 할애할 수 없다. 따라서 전체 영상의 일부분을 대상으로 점진적으로 누적영상을 배경영상에 적용함으로 실시간 환경에서의 배경영상의 변화에 의한 잡음을 최소화 하도록 하였다.

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Study of Low Temperature Solution-Processed Al2O3 Gate Insulator by DUV and Thermal Hybrid Treatment (DUV와 열의 하이브리드 저온 용액공정에 의해 형성된 Al2O3 게이트 절연막 연구)

  • Jang, Hyun Gyu;Kim, Won Keun;Oh, Min Suk;Kwon, Soon-Hyung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.33 no.4
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    • pp.286-290
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    • 2020
  • The formation of inorganic thin films in low-temperature solution processes is necessary for a wide range of commercial applications of organic electronic devices. Aluminum oxide thin films can be utilized as barrier films that prevent the deterioration of an electronic device due to moisture and oxygen in the air. In addition, they can be used as the gate insulating layers of a thin film transistor. In this study, aluminum oxide thin film were formed using two methods simultaneously, a thermal process and the DUV process, and the properties of the thin films were compared. The result of converting aluminum nitrate hydrate to aluminum oxide through a hybrid process using a thermal treatment and DUV was confirmed by XPS measurements. A film-based a-IGZO TFT was fabricated using the formed inorganic thin film as a gate insulating film to confirm its properties.

Laser Strengthening of $35kgf/\textrm{mm}^2$ Grade Steel Sheet far Automobile (자동차용 $35kgf/\textrm{mm}^2$급 강판의 레이저 강화)

  • Suh, Jeong;Lee, Jae-Hoon;Kim, Jeong-O;Oh, Sang-Jin;Cho, Won-Suk;Lee, Doo-Hwan;Shin, Chirl-Soo;Lee, Moon-Yong;Lee, Gyu-Hyun
    • Journal of Welding and Joining
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    • v.20 no.1
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    • pp.34-40
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    • 2002
  • The laser strengthening of $35kgf/\textrm{mm}^2$ grade steel sheet is investigated by using $CO_2$ laser beam irradiation. The increase of tensile strength is dominated by the number of fully penetrated melting lines. Also, the optimal laser irradiation pattern is obtained by 3-point bending test. Local laser strengthening clay be effective for the weight reduction of automobile components where the tailored welded blank can not be applied.

A Study on Characterization of Surface and Pore for Ag-impregnated Activated Carbon (은이 침착된 활성탄의 표면과 세공특성에 관한 연구)

  • Kim, Jong-Gyu;Oh, Won-Chun;Kim, Myoung-Kun
    • Applied Chemistry for Engineering
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    • v.9 no.5
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    • pp.729-733
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    • 1998
  • The surface structure and the pore size distribution of the activated carbon impregnated with silver have been investigated. It has been confirmed that the impregnants had an effect only on the external surface, not on the internal surface and that adsorption isotherms of both impregnated and non-impregnated activated carbons were classified as a typical BET type-I. As the amount of the impregnants increased, the amounts of adsorption, the specific surface area, and the micropore volume decreased and the window blocking was observed. The average pore diameter of the activated carbon impregnated with silver was observed to show the constant values regardless of the amount of the impregnants.

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The complete chloroplast genome of Zoysia macrostachya (Poaceae): Insights into intraspecific variations and species delimitation of the Zoysia species

  • OH, Sung-Dug;LEE, Seong-Kon;YUN, Doh-Won;SUN, Hyeon-Jin;KANG, Hong-Gyu;LEE, Hyo-Yeon;XI, Hong;PARK, Jongsun;LEE, Bumkyu
    • Korean Journal of Plant Taxonomy
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    • v.51 no.3
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    • pp.326-331
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    • 2021
  • The complete chloroplast genome of Zoysia macrostachya Franch. & Sav. isolated in Korea is 135,902 bp long (GC ratio is 38.4%) and has four subregions; 81,546 bp of large single-copy (36.3%) and 12,586 bp of small single-copy (32.7%) regions are separated by 20,885 bp of inverted repeat (44.1%) regions, including 130 genes (83 protein-coding genes, eight rRNAs, and 39 tRNAs). Thirty-nine single nucleotide polymorphisms and 11 insertions and deletion (INDEL) regions were identified from two Z. macrostachya chloroplast genomes, the smallest among other Zoysia species. Phylogenetic trees show that two Z. macrostachya chloroplast genomes are clustered into a single clade. However, we found some incongruency with regard to the phylogenetic position of the Z. macrostachya clade. Our chloroplast genome provides insights into intraspecific variations and species delimitation issues pertaining to the Zoysia species.

The Effect of the Introduction of the Express Highspeed Railway in Korea

  • KANG, SungWook;OH, SukMun;KIM, GyuBae
    • East Asian Journal of Business Economics (EAJBE)
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    • v.10 no.4
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    • pp.47-54
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    • 2022
  • Purpose - In today's era of carbon neutrality, railways need to find ways to improve usability and efficiency. Accordingly, this study examines the effect of introducing express highspeed railways into the Korean public transportation system and suggests some practical guidelines. One concern in the Korea railway sector is that low scheduled speeds contrast with the highspeed railway system design. Research design, data, and methodology - Current literature and foreign cases are analyzed. Subsequently, using data from the Korean Railroad Research Institute, a benefit analysis is conducted based on expanded track capacity and the saving of time owing to the introduction of the express highspeed railway. Result - The express highspeed railway system is expected to increase the number of train lines from 262 to 348 and the scheduled speed from 168.3km/h to 192.2km/h. Considering reduced time value, the economic effect is about 80 million won per year. Conclusion - The findings suggest that the express highspeed railway is a promising option to improve efficiency and increase customer utility. This study contributes to the literature by initiating a discussion on the express system in Korea; practically, it offers railway operators guidelines for improving highspeed railway system efficiency that can be transformed into a variety of marketing options.

A Study on Load Cell Development by means of a Nano-Carbon Piezo-resistive Composite and 3D printing (탄소나노튜브 복합소재 전왜 특성과 3D 프린팅을 활용한 로드셀 개발 연구)

  • Kang, Inpil;Joung, Kwan Young;Choi, Beak Gyu;Kim, Sung Yong;Oh, Gwang Won;Kim, Byung Tak;Baek, Woon Kyung
    • Journal of Drive and Control
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    • v.17 no.4
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    • pp.97-102
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    • 2020
  • This paper presents the basic research for the design and fabrication of a 3D-printed load cell made of NCPC (nano-carbon piezo-resistive composite). We designed a structure that can resonate at a low frequency range of about 5-6 Hz with ANSYS using sensitivity analysis and a response surface method. The design was verified by fabricating the device with a low-quality commercial 3D printer and ABS filament. We conducted a feasibility test for a commercial sensor using 1000 cyclic load tests at 0.3 Hz in a material testing system. A manufacturing process for the 3D printer filament based on the NCPC was also developed using the nano-composite process.

A Study on the Environmental-Based Turning Characteristics of Multi-Purpose Agricultural Robots (다목적 농업 로봇의 농작업 환경 기반 선회 특성 연구)

  • Lee, Ji-Won;Kang, Minsu;Park, Huichang;Cho, Yongjun;Oh, Jangseok;Kim, Min-Gyu;Seo, Kap-Ho;Park, Min-Ro
    • The Journal of Korea Robotics Society
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    • v.16 no.4
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    • pp.319-326
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    • 2021
  • To improve the driving performance and work efficiency of the multi-purpose agricultural robot, this paper conducted a study on the turning and steering characteristics of the robot platform according to the characteristics of the working machine coupled to the multi-purpose agricultural robot considering the agricultural environment. First, the size and characteristics of the developed multi-purpose agricultural robot platform and working machine, and the targeted field farming work environment are analyzed. And based on this analysis, the problems that arise in multi-purpose robots with conventional turning methods are quantitatively presented. And to overcome this problem, an improved turning and steering method for multi-purpose agricultural robots is proposed considering the characteristics of various workstations and the agricultural working environment. Finally, by applying the proposed method, the turning characteristics of the multi-purpose agricultural robot according to the working machine are analyzed and the effectiveness of the proposed method is verified.