• 제목/요약/키워드: Jang suk-sun

검색결과 280건 처리시간 0.026초

강제 입수에 의한 슬래밍 현상에 관한 실험적 연구 (An Experimental Study on Slamming Phenomenon by Forced Impact)

  • 남종오;강효동;정장영;권순홍;최한석
    • 한국해양공학회지
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    • 제21권1호
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    • pp.40-44
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    • 2007
  • This paper presents the experimental results on slamming phenomenon. The air pressure cylinder was used to ensure repeatability of the impact. The results showed that the adopted experimental technique was excellent in terms of repeatability, compared to that of the free drop tests. The pressure time histories, magnitude of peak pressure and the behavior of jetspray were obtained. The flat specimen was tested for various incident angles. To estimate the incident speed of the specimen, a high-speed camera was used. The high-speed camera was also a useful tool in understanding the behavior.

실 배전 계통 현장에서의 전압 측정값을 Database로 연동 하는 연구 (A Study on Interconnecting Measured Voltage Data To Database)

  • 안재윤;고석남;장선주;김태완;김척기;김수한;김재언
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 A
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    • pp.372-374
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    • 2003
  • 전력 계통에서의 안정적인 전기 공급과 전기 품질 수준의 유지 관리를 위해 전압 측정 Database를 이용한 분석이 필요하게 된다. 본 논문에서는 실 배전 계통에서 측정될 수 있는 RMS 간과 사고 시 전압을 저가형 전력 품질 모니터링 시스템을 통해 서버 컴퓨터로 데이터를 전송하여 Database에 저장 처리 할 수 있는 프로그램을 Delphi 언어로 개발하였다. 이는 구축된 Database를 이용 전력 품질을 분석하고 진단하는데 사용된다.

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$SrTiO_3$ 장벽층을 이용한 경사형 모서리 접합의 터널링 자기저항 특성연구 (Tunneling Magnetoresistance of a Ramp Edge Junction with $SrTiO_3$ Barrier Layer)

  • Lee, Sang-Suk;Kim, Young-Il;Hwang, Do-Guwn;Kim, Sun-Wook;Kungwon Rhie;Rhee, Jang-Roh
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2002년도 동계연구발표회 논문개요집
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    • pp.174-175
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    • 2002
  • A ramp-type tunneling magnetoresistance (TMR) junction having structure NiO(60 nm)/pinned Co(10 nm)MiO(60 nm)/barrier SrTiO$_3$(2-10 nm)/free NiFe(10 nm) with the 15 degree slope was investigated. We obtained nonlinear I(V) characteristics for ramp-type tunneling junctions that have distinctive difference with and without applied magnetic field. In the barrier SrTiO$_3$ thickness of 4 nm, the TMR was about 52% at a bias voltage of 50 mV. (omitted)

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자료기간에 따른 확률강우량 산정과 기준강우량을 초과하는 호우사상의 특성 분석 (Probability Precipitation Estimates According to the Date Periods and Characteristics Analysis of Rainfall Events Above Threshold)

  • 문장원;오태석;문영일;윤선권
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2010년도 학술발표회
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    • pp.1541-1545
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    • 2010
  • 최근 이상기후 및 기후변화로 인하여 전 세계의 피해가 증가하고 있다. 하지만 그 피해를 최소화하기 위하여 과도한 비용을 지출 할 수 없기 때문에 적정 설계 빈도에 맞는 치수 정책을 수립한다. 본 연구는 적정 설계 빈도의 설계를 위해 자료기간에 따른 확률강우량의 변화 특성에 대해 분석 하였고, 빈도별 확률강우량을 초과하는 강우사상의 시간적 특성을 분석하기 위해 초과횟수를 산정하여 경향성 분석을 수행하였다. 분석 대상 자료는 기상청에서 관할하고 있는 관측소 중에서 비교적 장기간의 자료를 보유하고 있는 16개 지점을 선정하여 분석하였다. 선정된 지점을 관측년수를 3가지로 나누어 구분하여 빈도해석을 실시하였고, 그 결과 많은 지역에서 확률강우량이 증가하는 것을 확인 할 수 있었다. 또한 빈도해석을 통해 산정된 확률강우량으로 기준을 정하였고, 그 기준을 초과하는 초과횟수를 산정하여 경향성 분석을 수행하였다.

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High Oxygen Sensitivity of Nanocrystalline Ceria Prepared by a Thermochemical Process

  • Lee, Dong-Won;Yu, Ji-Hoon;Lim, Tae-Soo;Jang, Tae-Suk
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.416-417
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    • 2006
  • Nanostructured ceria powder was synthesized by a thermochemical process and investigated its applicability for an oxygen gas sensor. An amorphous precursor powders prepared by spray drying a cerium-nitrate solution were transformed successfully into nanostructured ceria by heat-treatment in air atmosphere. The powders were a loose agglomerated structure with extremely fine $CeO_2$ particles about 15 nm in size, resulting in a very high specific surface area $(110\;m^2/g)$. The oxygen sensitivity and the response time $t_{90}$ measured at sintered sample at $1000^{\circ}C$ was about -0.25 and very short, i.e., $3{\sim}5$ seconds, respectively.

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경량충격음 차단성능 실험실 측정방법 고찰 (A Survey on the Laboratory Measurements of Impact Sound Insulation of Floors)

  • 송민정;장길수;고성석;김선우
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.976-979
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    • 2004
  • The KS of 'Laboratory Measurement of Impact Sound Insulation of Floors' is not established yet. To establish this KS, present conditions of domestic laboratory test facilities for measuring impact sound insulation of floors in laboratory and current researches were reviewed As a result the outline of 'Laboratory Measurement of Impact Sound Insulation of Floors' is suggested.

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Development of Redundant Levitation and Guidance Control System of the Urban and Medium to High Speed Magnetic Levitation Train

  • Cho, Yeon-Hwa;Lee, Sun-Hee;Jang, Kyung-Hyun;Lee, Sang Suk;Lee, Kyoung-Bok;Park, Doh-Young
    • International Journal of Railway
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    • 제8권1호
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    • pp.21-29
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    • 2015
  • This study focuses on the performance enhancement of the levitation and guidance control system in urban and medium-to high-speed magnetic levitation trains. A levitation control system, which is currently being tested in Yeongjongdo, is a single controller that is neither designed nor produced on the basis of redundancy. Hence, vehicular stability and reliability should be improved for the situation in which levitation failure occurs because of a breakdown in a controller during vehicle operation. In addition, the control system should be developed to control electromagnetic levitation considering changes in normal force according to changes in the driving force of the propulsion system.

In vitro Stimulation of NK Cells and Lymphocytes Using an Extract Prepared from Mycelial Culture of Ophiocordyceps sinensis

  • Sun-Hee Jang;Jisang Park;Seung-Hwan Jang;Soo-Wan Chae;Su-Jin Jung;Byung-Ok So;Ki-Chan Ha;Hong-Sig Sin;Yong-Suk Jang
    • IMMUNE NETWORK
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    • 제16권2호
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    • pp.140-145
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    • 2016
  • Ophiocordyceps sinensis is a natural fungus that has been valued as a health food and used in traditional Chinese medicine for centuries. The fungus is parasitic and colonizes insect larva. Naturally occurring O. sinensis thrives at high altitude in cold and grassy alpine meadows on the Himalayan mountain ranges. Wild Ophiocordyceps is becoming increasingly rare in its natural habitat, and its price limits its use in clinical practice. Therefore, the development of a standardized alternative is a great focus of research to allow the use of Ophiocordyceps as a medicine. To develop an alternative for wild Ophiocordyceps, a refined standardized extract, CBG-CS-2, was produced by artificial fermentation and extraction of the mycelial strain Paecilomyces hepiali CBG-CS-1, which originated from wild O. sinensis. In this study, we analyzed the in vitro immune-modulating effect of CBG-CS-2 on natural killer cells and B and T lymphocytes. CBG-CS-2 stimulated splenocyte proliferation and enhanced Th1-type cytokine expression in the mouse splenocytes. Importantly, in vitro CBG-CS-2 treatment enhanced the killing activity of the NK-92MI natural killer cell line. These results indicate that the mycelial culture extract prepared from Ophiocordyceps exhibits immune-modulating activity, as was observed in vivo and this suggests its possible use in the treatment of diseases caused by abnormal immune function.