• Title/Summary/Keyword: Choi Je-woo

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An Experimental Study on the Property of Strength for kinds and Replacement ratio of Admixture under Low Temperature (저온 환경하에서의 혼화재 종류 및 대체율에 따른 콘크리트의 강도발현특성에 관한 연구)

  • Kim, Ho-Soo;Jun, Soon-Je;Ban, Seong-Soo;Choi, Sung-Woo;Ryu, Deuk-Hyun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.687-690
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    • 2005
  • Recently, to consider financial and constructive aspect, usage of Admixture, like Blast- Furnace Slag and Fly-Ash, are increased. These mineral admixtures, a by-product of steel industry, have many advantage, to reduce the heat of hydration, increase in ultimate strength, improve workability and etc. But it also reduces early-age strength, so it is prevented from using of Blast-Furnace Slag at cold-weather-concrete. In this study, for the purpose of increasing usage of mineral admixtures, like Blast-Furnace Slag and Fly ash, it is investigated the strength properties of concrete subjected to under low temperature According to this study, if early curing is carried out before having frost damage, the strength of concrete, subjected to frost damage, is recovered. And to consider increasing effect of strength, it is more effective to use of mineral admixtures, especially to use blast furance slag.

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A Tool Pack Mechanism for DRM Interoperability

  • Choi, Bum-Suk;Byun, Young-Bae;Nam, Je-Ho;Hong, Jin-Woo
    • ETRI Journal
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    • v.29 no.4
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    • pp.539-541
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    • 2007
  • As the number of digital content service providers increases, a variety of digital rights management (DRM) systems appear without supporting interoperability. The lack of interoperability in DRM systems causes inconvenience to customers, especially when they want to play content through multiple devices manufactured by different vendors. In this letter, we propose a novel method to support interoperability between different DRM systems. The proposed technique aims to build an open framework structure which satisfies DRM vendors' requirements by enhancing the security of intellectual property management and the protection tools.

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Preliminary X-Ray Diffraction Study of Glutathione S-Transferase from Pseudomonas sp. DJ77

  • Choi, Heung-Soo;Woo, Ju-Rang;Lee, Jung-Hee;Chung, An-Sik;Ryu, Seong-Eon;Kim, Young-Chang;Chung, Yong-Je
    • BMB Reports
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    • v.30 no.4
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    • pp.296-298
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    • 1997
  • A bacterial glutathione S-transferase from Pseudomonas sp. DJ77 has been crystallized. The crystals diffract to at least $2.3\;\AA$ resolution, and belong to the orthorhombic space group $P2_{1}2_{1}2_{1}$, with cell parameters $a=97.4\;\AA,\;b=100.3\;\AA$, and $c=46.0\;\AA$. There is one dimer molecule of pGST per crystallographic asymmetric unit. with the crystal volume per protein mass of $2.34\;\AA^3/dalton$ and a solvent content of about 47% (v/v).

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Effect of Dispersion Technique on Heat Transfer Properties of Transformer Oil with Nanoparticles (변압기 나노절연유의 열전달특성에 미치는 분산기술의 영향)

  • Song, Hyun-Woo;Choi, Cheol;Oh, Je-Myung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.151-152
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    • 2005
  • Both $Al_2O_3$ and AlN nanopowders with diameters from ${\mu}m$ to mm were bead-milled and surface-modified by stabilizing agent. The size of bead-milled nanoparticles compared with the primary powder was effectively decreased and was dependent on milling time and bead size. The results of dispersion stability analysis indicated that chemical bonding between nanoparticles and surfactant is more effective than chemical adsorption to prepare the stable transformer oils containing nanoparticles. In this study, the thermal conductivity of the transformer oils containing nanoparticles was measured by transient hot-wire and laser flash methods.

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A Study on the Nano-Lithography using FE-tip (FE-tip을 이용한 Nano-Lithography 기술에 관한 연구)

  • Choi, Je-Hyuk;Park, Sun-Woo;Kim, Chul-Ju
    • Proceedings of the KIEE Conference
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    • 1999.11d
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    • pp.1160-1163
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    • 1999
  • In this study, we developed FE-tip lithography system that could apply to multi-tip system and did lithography using FE-tip. The software that control FE-tip lithography system, was proposed for acquiring more adaptive data to compensate the effect of fluctuation. We found that the fluctuation effect was reduced. The minimum line width was related to applied voltage and we observed a movement of Z-axis piezo stage to correct the error of this system. When FE current was 5nA, scanning speed was $3{\mu}m/sec$ and applied voltage was 200V, we made a line pattern which had minimum line width of 614 nm. If we reduce applied voltage to several decades and increase scanning speed to $20{\mu}m/sec$, it is possible to set the minimum line width of 100 nm. The proposed system can be easily applied to multi FE-tip lithography system.

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Eosinophilic Furunculosis of the Face in a Dog (개의 안면부 호산구성 종기증 1예)

  • Jun JeGal;Choi Eul soo;Lee Chang woo
    • Journal of Veterinary Clinics
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    • v.22 no.1
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    • pp.74-75
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    • 2005
  • A 4 year-old Doberman Pinscher was presented with periocular skin lesions which has developed after climbing a mountain with the client. Cytologic preparations of the periocular skin lesions revealed marked eosinophilic infiltration, and a few neutrophils, lymphocytes and epithelial cells. These findings are consistent with eosinophilic furunculosis of the face typically in medium breed dogs. The patient was administered orally with prednisolone 1mg/kg for 2 weeks. The skin lesions were regressed responsively. The patient has no recurrent signs.

Design and Performance Evaluation of MR Damper for Integrated Isolation Mount (통합제진마운트용 MR 댐퍼의 설계 및 성능 평가)

  • Seong, Min-Sang;Lim, Seung-Gu;Choi, Seung-Bok;Kim, Cheol-Ho;Woo, Je-Kwan
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.11
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    • pp.1046-1051
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    • 2010
  • This paper presents design and performance evaluation of magnetorheological(MR) damper for integrated isolation mount. The MR damper needs two functions for the integrated isolation mount. The one is vibration absorption and the other is isolation of vibration transmission. For vibration absorption, the MR damper requires wide damping force range. And for isolation of vibration transmission, the friction of MR damper needs to be eliminated. In order to achieve this goal, a novel type of MR damper is originally designed in this work. Subsequently, the MR damper is mathematically modeled and its damping force characteristics are evaluated. In addition, the vibration control performance of the MR damper associated with the stage mass is evaluated. From the result, this paper evaluates the performance of MR damper for integrated isolation mount.

Study of Effect of tunnelling on pile group - Numerical Analysis (터널 굴착이 무리말뚝거동에 미치는 영향에 대한 수치해석연구)

  • Woo, Seung-Je;Choi, Go-Ny;Yoo, Chung-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09b
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    • pp.96-103
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    • 2010
  • This paper presents of effect of tunneling on pile group of being operated bridge using Three-dimensional numerical modeling to study the effect of coordination of tunneling location under discontinuous group pile. In order to find idealistic tunneling location that causes settlement, change of stress on the piles and movement of soil at a minimum, a fully coupled 3D finite element model is adopted. The study contains pile settlement, axial force on each piles in the group, axial displacement of piles and soil behaviour caused by tunneling. Based on the result some insights into the pile behavior due to tunneling obtained from numerical analysis were mentioned and discussed.

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Comparative Analysis of Various Industrial By-Products Pozzolanic Activity (다양한 산업부산물들의 포졸란 반응성 비교분석)

  • Choi, Ik-Je;Kim, Ji-Hyun;Chung, Chul-Woo;Lee, Soo-Yong
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.05a
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    • pp.32-33
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    • 2016
  • In this work, pozzolanic activities of various waste materials were compared with those of well-known pozzolanic materials. Uncondensed and densified silica fume, two ASTM class F fly ashes with different calcium contents, and bentonite powder, ceramic powder obtained from wash basin, and waste glass wool, which can possibly possess pozzolanic property were chosen for comparison. Drop in electrical conductivity at 40℃ saturated lime solution was measured for each materials. The amount of Ca(OH)2 decomposed from cement paste at 450~500℃ was also measured used to evaluate pozzolanic activity. The 28 day compressive strength were used to observe the mechanical property enhanced by various waste materials.

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Build Up Support Function Capability by Introduction of Shared Service Center (Shared Service Center 도입을 통한 지원 기능 역량 강화 방안)

  • Joo, Min-Woo;Choi, Sung-Rak;Park, Gi-Han;Yun, Hyung-Je
    • 한국IT서비스학회:학술대회논문집
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    • 2005.05a
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    • pp.575-579
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    • 2005
  • A Shared Services center (SSC) is created by removing common administrative functions from operational divisions within an organization, and centralizing the functions in a separate centre. SSC helps supporting organizations to focus on core activities and to achieve cost reduction as well as service quality enhancement. In contrast to many leading global companies which has been adopted SSCs from early 90's. A Company's HR SSC which has opened this year is the first genuine SSC practice in Korea. Centering on the case of A Company' s HR SSC implementation, we discussed on some practical implications for companies which has future plan to introduce a shared service center.

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