• Title/Summary/Keyword: Choi Je-woo

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Fabrication and analysis of optical micro-pyramid array-patterns (광학 마이크로 피라미드 패턴의 제조 및 광특성 해석)

  • Lee, Je-Ryung;Jeon, Eun-Chae;Je, Tae-Jin;Woo, SangWon;Choi, Do-Sun;Yoo, Yeong-Eun;Kim, Hwi
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.4
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    • pp.7-12
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    • 2014
  • A transparent poly methyl methacrylate (PMMA) optical micro-pyramid array-pattern is designed and fabricated using an injection modeling technique. The device's optical characteristics are tested and analyzed theoretically. In the optical pattern generated using the fabricated PMMA pattern, the components, due to not only refraction but also diffraction, are observed simultaneously. Wave optic modeling and analysis reveals that the energy ratio between the diffraction and refraction in the optical pattern are dependent on the critical dimension of the optical pattern such that the refraction and diffraction tend to be directly and inversely proportional to the pattern dimension, respectively.

N-4-Substituted-benzyl-N'-tert-butylbenzyl Thioureas as Vanilloid Receptor Ligands: Investigation on the Role of Methanesulfonamido group in Antagonistic Activity

  • Park, Hyeung-Geun;Choi, Je-Yeon;Choi, Sea-Hoon;Park, Mi-Kyung;Lee, Ji-Hye;Suh, Young-Ger;Cho, Ha-Won;Oh, Uh-Taek;Lee, Ji-Youn;Kang, Sang-Uk;Lee, Jee-Woo;Kim, Hee-Doo;Park, Young-Ho;Jeong, Yeon-Su;Choi, Jin-Kyu;Jew, Sang-Sup
    • Proceedings of the PSK Conference
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    • 2003.10b
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    • pp.173.2-173.2
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    • 2003
  • Vanilloid receptor I (VR1) is a nonselective cation ion channel placed in the plasma membrane of peripheral sensory neurons that is potential target for analgesia A series of N-4-substituted-benzyl-N'-tert-butylbenzyl thioureas were prepared for the study of their agonistic/antagonistic activities to the vanilloid receptor in rat DRG. Their structure-activity relationship in reveals that not only the two oxygens and amide hydrogen of sulfonamido group but also the optimal size of methyl in methanesulfonamido group play an integral role for the antagonistic activity on vanilloid receptor.

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Inhibition of glutamate dehydrogenase and insulin secretion by KHG26377 does not involve ADP-ribosylation by SIRT4 or deacetylation by SIRT3

  • Kim, Eun-A;Yang, Seung-Ju;Choi, Soo-Young;Lee, Woo-Je;Cho, Sung-Woo
    • BMB Reports
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    • v.45 no.8
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    • pp.458-463
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    • 2012
  • We investigated the mechanisms involved in KHG26377 regulation of glutamate dehydrogenase (GDH) activity, focusing on the roles of SIRT4 and SIRT3. Intraperitoneal injection of mice with KHG26377 reduced GDH activity with concomitant repression of glucose-induced insulin secretion. Consistent with their known functions, SIRT4 ribosylated GDH and reduced its activity, and SIRT3 deacetylated GDH, increasing its activity. However, KHG26377 did not affect SIRT4-mediated ADP-ribosylation/inhibition or SIRT3-mediated deacetylation/activation of GDH. KHG26377 had no effect on SIRT4 protein levels, and did not alter total GDH, acetylated GDH, or SIRT3 protein levels in pancreatic mitochondrial lysates. These results suggest that the mechanism by which KHG26377 inhibits GDH activity and insulin secretion does not involve ADP-ribosylation of GDH by SIRT4 or deacetylation of GDH by SIRT3.

Modeling and Vibration Control of Small-sized Magneto-rheological Damper (소형 MR 댐퍼의 모델링 및 진동제어)

  • Lee, Jong-Woo;Seong, Min-Sang;Woo, Je-Kwan;Choi, Seung-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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    • pp.344-349
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    • 2012
  • This paper presents a new small-sized damper featuring magneto-rheological (MR) fluid which can be applied to vibration control system. The proposed MR damper consists of cylinder, piston, a couple of bearings, oil-seals and magnetic circuit which has two coils. In this damper, approximately 5cc of MR fluid is used. The damping force of the MR damper is designed to be followed by linear shear-mode Bingham-plastic model. In order to verify the performance of the MR damper, an experimental apparatus is established. In the experimental test, the damping force of the MR damper is measured with respect to time, displacement and velocity. In addition, the time response of MR damper is measured when 1A of step current is applied. Finally, The proposed small MR damper is applied to vibration control. In this process, a simple 1-DOF system is modeled and controlled using PID controller.

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Modeling and Vibration Control of Small-sized Magneto-rheological Damper (소형 MR 댐퍼의 모델링 및 진동제어)

  • Lee, Jong-Woo;Seong, Min-Sang;Woo, Je-Kwan;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.11
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    • pp.1121-1127
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    • 2012
  • This paper presents a new small-sized damper featuring magneto-rheological(MR) fluid which can be applied to vibration control system. The proposed MR damper consists of cylinder, piston, a couple of bearings, oil-seals and magnetic circuit which has two coils. In this damper, approximately 5cc of MR fluid is used. The damping force of the MR damper is designed to be followed by linear shear-mode Bingham-plastic model. In order to verify the performance of the MR damper, an experimental apparatus is established. In the experimental test, the damping force of the MR damper is measured with respect to time, displacement and velocity. In addition, the time response of MR damper is measured when 1A of step current is applied. Finally, the proposed small MR damper is applied to vibration control. In this process, a simple 1-DOF system is modeled and controlled using PID controller.

Isolation and Characterization of a Lymantria dispar Multinucleocapsid Nucleopolyhedrovirus Isolate in Korea

  • Shim, Hee-Jin;Roh, Jong-Yul;Choi, Jae-Young;Li, Ming-Shun;Woo, Soo-Dong;Oh, Hyun-Woo;Boo, Kyung-Saeng;Je, Yeon-Ho
    • Journal of Microbiology
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    • v.41 no.4
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    • pp.306-311
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    • 2003
  • In Korea, a Lymantria dispar multinucleocapsid nucleopolyhedrovirus, LdMNPV-NM, was isolated and characterized from dead L. dispar larvae. The polyhedra of LdMNPV-NM were irregularly shaped with a diameter of $1.62{\pm}0.33{\mu}m$. Numerous virions comprised of the multinucleocapsid were evident in the electron microscopic examination of the polyhedra cross sections. These polyhedra were composed of a major protein of 30 kDa. The restriction enzyme digestion patterns of LdMNPV-NM showed that this isolate had some different fragments from those of the Gypchek LdMNPV isolate, although their overall profiles were similar. The deduced amino acid sequence of the enhancin gene of LdMNPV-NM showed differences when compared to previously reported enhancin genes of other LdMNPV strains. These results suggested that the LdMNPV-NM isolate from Korea was a new NPV strain and had a new enhancin gene.

Improving Visual Accessibility for Color Vision Deficiency Based on MPEG-21

  • Yang, Seung-Ji;Ro, Yong-Man;Nam, Je-Ho;Hong, Jin-Woo;Choi, Sang-Yul;Lee, Jin-Hak
    • ETRI Journal
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    • v.26 no.3
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    • pp.195-202
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    • 2004
  • In this paper, we propose a visual accessibility technique in an MPEG-21 framework. In particular, MPEG-21 visual accessibility for the colored-visual resource of a digital item is proposed to give better accessibility of color information to people with color vision deficiency (CVD). We propose an adaptation system for CVD as well as a description of CVD in MPEG-21. To verify the usefulness of the proposed method, computer simulations with CVD and color adaptation were performed. Furthermore, a statistical experiment was performed using volunteers with CVD in order to verify the effectiveness of the proposed visual accessibility technique in MPEG-21. Both the experimental and simulation results show that the proposed adaptations technique can provide better color information, particularly to people with CVD.

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The Manufacture and Output Characteristics of Small PV System Using Solar Tracking System (소용량 태양 추적장치를 이용한 PV 시스템제작 및 출력특성)

  • Lim, Hong-Woo;Park, Je-Woong;Choi, Mun-Han;Kim, Pyoung-Ho;Jang, Yong-Hae;Cho, Geum-Bae;Baek, Hyung-Lae
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.1328-1331
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    • 2002
  • Nowaday, almost of practical energy is come from the fossil fuel, such as coal, oil and gas those are limited and caused the environmental pollution. For these reason. solar energy is come into notice as a new alternative energy source to overcome the shortage of electricity in the $future^{(1)}$. In this paper, small PV system using photo sensor for tracking sun is developed and is verified by experiments.

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The Joining Characteristics of Butt Friction Stir Welded C1020/Al6063 (C1020/Al6063 이종 합금의 맞대기 마찰교반접합의 접합특성)

  • Ko, Young-Bong;Choi, Jun-Woong;Cho, Je-Hyoung;Kim, Hyen-Woo;Park, Kyeung-Chae
    • Journal of the Korean institute of surface engineering
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    • v.42 no.5
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    • pp.240-245
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    • 2009
  • The Friction Stir Welding (FSW) has mainly been used for making butt joints in Al alloys. Development of FSW would expand the number of applications. The FSW is a relatively solid-state joining process. This study possibility of a welding between C1020 and Al6063 by means of FSW has fundamentally clarified. The primary process parameters, such as a rotating speed, rotating direction of tool and off-set of pin periphery from materials interface were optimize, respectively.

The Structural Analysis and Experimental Verification for the Next Generation High Speed EMU (분산형 고속전철의 하중조건에 따른 정적 하중시험 평가)

  • Choi, Jeong-Yong;Jeong, Won-Wha;Park, Geun-Soo;Woo, Kwan-Je
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.307-313
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    • 2011
  • Hyundai Rotem Company has designed and manufactured the next generation high speed EMU bodyshell (M3-car). Korean Railway Safety Law specifies the loads vehicle bodies shall be capable of withstanding, identifies what material data shall be used and presents the principles to be used for design verification by analysis. Therefore, in order to fulfill the structural requirements, Hyundai Rotem Company has carried out Finite Element Analysis (FEA) and static load test to verify whether the carbody structure has enough strength to withstand the loads specified by Korean Railway Safety Law. This research contains the results obtained by the FE analysis and static load test. The FE analysis is carried out using NX I-DEAS 6.1 and specially designed test jigs and equipment are used for the load tests.

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