• Title/Summary/Keyword: Oh Gyu-won

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High Power-Factor Single-Stage Half-Bridge High Frequency Resonant Inver (고역률을 가지는 Single-Stage Half-Bridge 고주파 공진 인버터)

  • Won, Jae-Sun;Kim, Dong-Hee;Seo, Cheol-Sik;Cho, Gyu-Pan;Oh, Seung-Hoon;Jung, Do-Young;Bae, Yeong-Ho
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.1196-1198
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    • 2002
  • A novel single-stage half-bridge high frequency resonant inverter using ZVS(Zero Voltage Switching) with high input power factor suitable for induction heating applications is presented in this paper. The proposed high frequency resonant inverter integrates half-bridge boost rectifier as power factor corrector(PFC) and half-bridge resonant inverter into a single stage. The input stage of the half-bridge boost rectifier is working in discontinuous conduction mode (DCM) with constant duty cycle and variable switching frequency. So that a high power factor is achieved naturally. Simulation results through the Pspice have demonstrated the feasibility of the proposed inverter. This proposed inverter will be able to be practically used as a power supply in various fields as induction heating applications, DC-DC converter etc.

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Bacillus anthracis Spores Influence ATP Synthase Activity in Murine Macrophages

  • Seo, Gwi-Moon;Jung, Kyoung-Hwa;Kim, Seong-Joo;Kim, Ji-Cheon;Yoon, Jang-Won;Oh, Kwang-Keun;Lee, Jung-Ho;Chai, Young-Gyu
    • Journal of Microbiology and Biotechnology
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    • v.18 no.4
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    • pp.778-783
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    • 2008
  • Anthrax is an infectious disease caused by toxigenic strains of the Gram-positive bacterium Bacillus anthracis. To identify the mitochondrial proteins that are expressed differently in murine macrophages infected with spores of B. anthracis Sterne, proteomic and MALDI-TOF/MS analyses of uninfected and infected macrophages were conducted. As a result, 13 mitochondrial proteins with different expression patterns were discovered in the infected murine macrophages, and some were identified as ATP5b, NIAP-5, ras-related GTP binding protein B isoform CRAa, along with several unnamed proteins. Among these proteins, ATP5b is related to energy production and cytoskeletal rearrangement, whereas NIAP-5 causes apoptosis of host cells due to binding with caspase-9. Therefore, this paper focused on ATP5b, which was found to be down regulated following infection. The downregulated ATP5b also reduced ATP production in the murine macrophages infected with B. anthracis spores. Consequently, this study represents the first mitochondrial proteome analysis of infected macrophages.

Differences of Organizational Health and Customer Orientation by the Hospital Ownership (병원설립주체별 간호조직건강성이 고객지향성에 미치는 영향)

  • Lee, Gyu-Hee;Oh, Chang-Seok;Cho, Kyoung-Won
    • The Korean Journal of Health Service Management
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    • v.9 no.3
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    • pp.69-79
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    • 2015
  • Objectives : This study was conducted to verify the influence organizational health has on customer orientation by hospital ownership. Methods : This survey was conducted on a public hospital, private hospital, and religious hospital, respectively, during March 2014 and a total of 210 questionnaires were used in the analysis. ANOVA and regression analysis were used to analyze the collected data. Results : The management environment factor of organizational health was statistically significant in the public hospital compared to the private hospital. The reliability factor of customer organization was statistically significant in the public hospital and religious hospital respectively compared to the private hospital. For reactivity, the religious hospital was statistically significant compared to private hospital. A positive influence was shown in the vitality factor at the public hospital, and community orientation at the private hospital, while both community orientation and career showed effects at the religious hospital. ICU had a negative influence on customer orientation at the private hospital. Conclusions : The reason vitality had a relatively more important effect on customer orientation in the public hospital was due that age group of 20~29 was the dominant socio-demographic factor. Furthermore, the influence of community orientation on customer orientation in the private hospital and religious hospital may be related to the nurses' career.

A study of development of next generation terrestrial 4K & HD convergence transmission systems (차세대 지상파 4K & HD 융합방송을 위한 전송 시스템 개발에 관한 연구)

  • Oh, Jong-Gyu;Won, Yong-Ju;Lee, Jin-Sub;Kim, Joon-Tae
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2014.06a
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    • pp.122-125
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    • 2014
  • 세계적으로 아날로그 방송에서 디지털 방송으로의 전환이 마무리되고 있는 가운데, 앞으로 다가올 UHDTV 등 실감의 대용량 방송 및 방송 통신 융합 환경에 대비하기 위한 새로운 차기 방송 표준에 관한 연구의 필요성이 날로 높아져 가고 있다. 특히, 저해상도 서비스에 머물러 있던 이동 방송에서는 기존 HD급의 서비스 제공이 가능한 이동 실감방송으로 진화하기 때문에 고정/이동 방송 서비스가 동시에 가능한 고효율 전송 원천 기술 개발이 이루어질 필요가 있다. 이에 최근 지상파 단일 채널을 통해 4K & HD 방송 서비스를 동시에 제공하는 융합방송 시스템 개발에 대해서 연구가 진행되고 있다. 본 논문에서는 지상파 단일 채널을 통해 4K & HD 융합방송 서비스를 제공하기 위해 필요한 전송 요구 사항들에 대해서 분석하고, 효율적인 데이터 전송을 위해 필요한 전송 시스템 및 다중화 기술에 관해서 알아보았다. 또한 분석한 데이터 전송률을 달성하기 위한 최적의 시스템 파라메터를 도출하고 분석하였다.

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A Study on Influence of Fuel Cell Performance by Hydrogen Odorant (수소가스 부취제가 연료전지의 성능에 미치는 영향 연구)

  • Han, Sang-Won;Oh, Seok-Hwan;Kim, Young-Gyu;Lee, Sung-Hun;Chae, Jae-Ou
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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    • pp.491-494
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    • 2008
  • The hydrogen fuel and fuel cell which have high energy efficiency and low pollutant emission are getting interest as an alternative energies due to the fossil fuel exhaust, green house effect and atmospheric pollutant problems. The hydrogen gas is very effective as an alternative energy. But, if it is leaked into the air it forms the mixed gas with the air then the danger of the explosion is risen up. So, the secure the safety is mostly important. In this research, to detect the leakage of the hydrogen rapidly, added the odorant materials which don't include the sulfur component into the hydrogen gas and researched on the effect of each odorant on the performance of the fuel cell. As the results, setting the cumulation electric power on the basis and comparing the pure hydrogen, 2,3-Butanedione 5ppm mixed gas 86.1%, 5-Ethylidene-2-Norbornene 17ppm mixed gas 88.2%, Isovaleraldehyde 10ppm mixed gas 74.8%, Ethyl Isobutyrate 2.2ppm mixed gas 93.5% of performance was shown.

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Hesperidin Attenuates Ultraviolet B-Induced Apoptosis by Mitigating Oxidative Stress in Human Keratinocytes

  • Hewage, Susara Ruwan Kumara Madduma;Piao, Mei Jing;Kang, Kyoung Ah;Ryu, Yea Seong;Han, Xia;Oh, Min Chang;Jung, Uhee;Kim, In Gyu;Hyun, Jin Won
    • Biomolecules & Therapeutics
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    • v.24 no.3
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    • pp.312-319
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    • 2016
  • Human skin cells undergo pathophysiological processes via generation of reactive oxygen species (ROS) upon excessive exposure to ultraviolet B (UVB) radiation. This study investigated the ability of hesperidin ($C_{28}H_{34}O_{15}$) to prevent apoptosis due to oxidative stress generated through UVB-induced ROS. Hesperidin significantly scavenged ROS generated by UVB radiation, attenuated the oxidation of cellular macromolecules, established mitochondrial membrane polarization, and prevented the release of cytochrome c into the cytosol. Hesperidin downregulated expression of caspase-9, caspase-3, and Bcl-2-associated X protein, and upregulated expression of B-cell lymphoma 2. Hesperidin absorbed wavelengths of light within the UVB range. In summary, hesperidin shielded human keratinocytes from UVB radiation-induced damage and apoptosis via its antioxidant and UVB absorption properties.

Biomechanical Effect of Total Disc Replacement on Lumbar Spinal Segment : A Finite Element Analysis (추간판 치환술이 요추분절에 미치는 생체역학적 영향 : 유한요소해석)

  • Park, Won-Man;Kim, Ki-Tack;Hong, Gyu-Pyo;Kim, Yoon-Hyuk;Oh, Taek-Yul
    • Korean Journal of Computational Design and Engineering
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    • v.13 no.1
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    • pp.58-66
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    • 2008
  • The artificial discs have recently used to preserve the motion of the treated segment in lumbar spine surgery. However, there have been lack of biomechanical information of the artificial discs to explain current clinical controversies such as long-term results of implant wear and excessive facet contact forces. In this study, we investigated the biomechanical effects of three artificial implants on the lumbar spinal segments by finite element analysis. The finite element model of intact lumbar spine(L1-S) was developed and the three implants were inserted in L4-L5 segment of the spine model. 5 Nm of flexion and extension moments were applied on the superior plate of L1 with 400 N of compressive load. Excessive motions and high facet contact forces at the surgical level were generated in the all three implanted models. In the flexion, the peak von-Mises stresses in the semi-constrained type implant was higher than those in the un-constrained type implant which would cause wear on the polyethylene core. The results of the study would provide a biomechanical guideline for selecting optimal surgical approach or evaluating the current design of the implants, or developing a new implant.

Aortoenteric Fistula -one case report- (대동맥장루 -1예 보고-)

  • Kim, Hyuck;Jung, Tae-Yol;Ban, Dong-Gyu;Chung, Won-Sang;Kim, Young-Hak;Kang, Jung-HO;Jee, Heng-Ok;Lee, Chul-Bum;Kwon, Oh-Jung;Kim, Kyung-Soo
    • Journal of Chest Surgery
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    • v.34 no.2
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    • pp.176-179
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    • 2001
  • 이차성 대동맥장루는 아주 드물며 대동맥-장골동맥의 재건수술의 중대한 합병증으로 발생할 수 있다. 이 질환은 진성 대동맥장루와 paraprosthetic enteric fistula 로 분류할 수 있다. 이러한 합병증의 예방, 진단 및 치료는 추구해야할 문제로 되어 있다. 염증성 가성동맥류로 복부대동맥 및 장골동맥을 인조혈관으로 치환한 후 41개월에 내시경으로 Paraprosthetic enteric Fistula로 진단되어 수술을 시행한 39세 남자환자를 치험하였기에 보고한다.

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A Study on the Configuration of Cost Items and the Identification of Cost Affecting Factors for the Decommissioning Cost Estimation of Nuclear Research Facilities (원자력연구시설 해체비용 산정을 위한 비용항목 구성 및 비용 영향인자 산출 방안)

  • Jeong Kwan-Seong;Lee Dong-Gyu;Lee Kune-Woo;Oh Won-Zin
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2005.11a
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    • pp.25-31
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    • 2005
  • The decommissioning cost estimation is the very essential procedure to establish the decommissioning plans for Nuclear Research Facilities. The cost estimation must be made in accordance with activity phase and facility installations. This paper shows how to configuring the cost items and identifying the effecting cost factors. In the end, these methods will be utilized as a tool and technique to develop the methodology of cost estimation and calculation program.

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A Study on the MTF of optical system with optical path difference (광경로차가 있는 광학기기의 변조전달함수에 관한 연구)

  • Che, Gyu-Shik;Jang, Won-Seok;Oh, Jake
    • Journal of Advanced Navigation Technology
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    • v.16 no.3
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    • pp.518-525
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    • 2012
  • The modulation transfer function is generally used as a method to estimate the characteristics of this kind of optical system because it cannot reappear or implement image of the object perfect. By the way, it is difficult to assess the optical system with existing MTF method since the reaction between diffraction and aberration of aperture is very complicate if the aberration is very small. The MTF has to be calculated considering the numerical aperture, defocusing, OPD and phase difference. We validate its feasibility using bessel function as an estimating method, and then realize it through illustration in this paper.