• 제목/요약/키워드: Yoon Jeung

검색결과 249건 처리시간 0.026초

ETABr 용액내에서 P-Nitrophenyldiphenylphosphinate의 탈인산화반응에 미치는 Benzimidazole의 촉매효과 (Dephosphpoylation of P-Nitrophenyldiphenylphosphinate by Benzimidazole Catalyzed with Ethyl tri-n-octyl Ammonium Bromide(ETABr))

  • 김정배;김학윤
    • 한국환경과학회지
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    • 제16권5호
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    • pp.641-647
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    • 2007
  • The phase transfer catalysis(PTC) reagent, ethyl tri-octyl ammonium bromide(ETABr), strongly catalyzes the reaction of p-nitrophenyi diphenyl phosphinate(p-NPDPIN) with benzimidazole(BI) and its anion($BI^{\theta}$). In ETABr solutions, the dephosphorylation reactions exhibit higher first order kinetics with respect to the nucleophile, BI, and ETABr, suggesting that reactions are occuring in small aggregates of the three species including the sub-strate(p-NPDPIN), whereas the reaction of p-NPDPIN with $OH^{\theta}$ is not catalyzed by ETABr. This behavior for the drastic rate-enhancement of the dephosphorylation is referred as 'aggregation complex model' for reaction of hydrophobic organic phosphinates with benzimidazole(BI) in hydrophobic quarternary ammonium salt(ETABr) solutions.

극초음속 추진과 관련된 초음속 연소 현상의 수치적 검증 (Computational Validation of Supersonic Combustion Phenomena associated with Hypersonic Propulsion)

  • 최정열;정인석;윤영빈
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 1998년도 춘계 학술대회논문집
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    • pp.117-122
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    • 1998
  • A numerical study is carried out to investigate the transient process of combustion phenomena associated with hypersonic propulsion devices. Reynolds averaged Navier-Stokes equations for reactive flows are used as governing equations with a detailed chemistry mechanism of hydrogen-air mixture and two-equation SST turbulence modeling. The governing equations are discretized by a high order accurate upwind scheme and solved in a fully coupled manner with a fully implicit time accurate method. At first, oscillating shock-induced combustion is analyzed and the comparison with experimental result gives the validity of present computational modeling. Secondly, the model ram accelerator experiment was simulated and the results show the detailed transient combustion mechanisms. Thirdly, the evolution of oblique detonation wave is simulated and the result shows transient and final steady state behavior at off-stability condition. Finally, shock wave/boundary layer interaction in combustible mixture is studied and the criterion of boundary layer flame and oblique detonation wave is identified.

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물이 채워진 소화 배관의 전파 차폐도 해석 (Analysis on Shielding Effectiveness of Electromagnetic Wave in Fire Pipes)

  • 김윤증
    • 한국화재소방학회논문지
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    • 제30권4호
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    • pp.94-102
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    • 2016
  • EMP 방호용 차폐 시설을 구축 할 때 소화 배관들의 방호 처리를 위하여 WBC 효과를 이용하며, 차폐도를 높이기 위해서 소화 배관 내부에 허니컴을 삽입한다. 이때 허니컴 단위 셀의 크기가 작으면 물의 흐름에 지장을 주며, 침전물에 의하여 소화 배관이 막히게 된다. 이것을 방지하기 위하여, 물의 분극손실에 의한 차폐도를 이용해서, 허니컴 셀의 크기는 키우고, 두께는 얇게 하면서도 요구하는 차폐도를 얻을 수 있는 설계 방법을 제시하였다.

외상성 경부 척수 손상 환자에서 동반된 소장 천공 : 증례보고 (Traumatic Cervical Spinal Cord Injury Patient with Jejunal Perforation)

  • 고승제;윤정석;윤정호
    • Journal of Trauma and Injury
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    • 제26권4호
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    • pp.319-322
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    • 2013
  • A 66 year-old woman had cervical spinal cord injury by an automobile. We performed emergency operation for partial quadriplegia. She recovered from motor weakness gradually, but complained of abdominal distension and mild dyspnea. A physical examination of her abdomen did not have tenderness and rebound tenderness. She underwent a decubitus view of chest X-ray due to aggravated dyspnea at postoperative 4 days. We detected free air gas of abdomen and immediately identified a cause of pneumoperitoneum by abdominal computed tomography. We performed an emergent laparotomy and confirmed a jejunal perforation. After an operation, she recovered well and is under rehabilitation.

동특성 분석을 통한 하우징의 구조건전성 평가 (The Evaluation of the Electronic Housing Structural Integrity Using Dynamic Analysis)

  • 이재은;최혜윤;김병준;이증;정오균
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2014년도 추계학술대회 논문집
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    • pp.54-59
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    • 2014
  • The rapid tactical operation and mobility are getting important to recently developed the guided weapon systems. And military wants multi-purposes equipment to carry the war more easily. So military wants to have the equipment that can apply without any distinction about environment. For this reason, the robust design is getting more important now to guarantee survivability of equipment. In this paper, we try to check about structural integrity of Fire Control Unit(FCU) which is one of the guided weapon system using dynamic FEM analysis.

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Electronic Structures of Graphene on Ru(0001) : Scanning Tunneling Spectroscopy Study

  • Jang, Won-Jun;Jeon, Jeung-Hum;Yoon, Jong-Keon;Kahng, Se-Jong
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.307-307
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    • 2011
  • Graphene is the hottest topic in condensed-matter physics due to its unusual electronic structures such as Dirac cones and massless linear dispersions. Graphene can be epitaxially grown on various metal surfaces with chemical vapor deposition processes. Such epitaxial graphene shows modified electronic structures caused by substrates. Here, local geometric and electronic structures of graphene grown on Ru(0001) will be presented. Scanning tunneling microscopy (STM) and spectroscopy (STS) was used to reveal energy dependent atomic level topography and position-dependent differential conductance spectra. Both topography and spectra show variations from three different locations in rippled structures caused by lattice mismatch between graphene and substrate. Based on the observed results, structural models for graphene on Ru(0001) system were considered.

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Electronic Structures of Graphene Intercalated by Oxygen on Ru(0001): Scanning Tunneling Spectroscopy Study

  • Jang, Won-Jun;Jeon, Jeung-Hum;Yoon, Jong-Keon;Kahng, Se-Jong
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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    • pp.114-114
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    • 2011
  • Graphene is the hottest topic in condensed-matter physics due to its unusual electronic structures such as Dirac cones and massless linear dispersions. Graphene can be epitaxially grown on various metal surfaces with chemical vapor deposition (CVD) processes. Such epitaxial graphene shows modified electronic structures caused by substrates. In the method for removal of the effect of substrate, there are bi, tri-layer graphene, gold intercalation, and oxygen intercalation. Here, We will present the changes of geometric and electronic structure of graphene grown on Ru(0001) by oxygen intercalation between graphene and Ru(0001). Using Scanning tunneling microscopy (STM) and spectroscopy (STS), we observed the aspect that the band gap features near the fermi level of graphene on Ru(0001) system is shifted and narrow. Based on the observed results, two effects by intercalated oxygen were considered.

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BT 실험실의 KMS를 위한 지식 생성 툴로써의 실험실정보관리시스템 설계 (Design of Laboratory Information Management System as a Knowledge Creation Tool for the KMS of BT Laboratory)

  • 배진;황윤민;노재정
    • 한국IT서비스학회:학술대회논문집
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    • 한국IT서비스학회 2003년도 춘계학술대회
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    • pp.428-435
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    • 2003
  • Post-Genome 시대의 Biotechnology(BT) 산업에 세계적으로 관심과 투자가 증가하고 있다. BT 산업은 기술 및 지식 집약적 특성상 R&D 활동이 중요하기에 BT 연구실의 실험 생산성 증가에 대한 연구가 필요하다. 이와 관련하여 연구실 지식경영과 지식경영시스템활용에 관한 연구가 활발히 진행되고 있다. 하지만 그 초점이 연구 지식들의 조직화, 체계화 및 검색기능 등의 원활한 지식 공급 시스템 구축에 있기에 효율적이고 효과적인 지식 생성 방안을 제시해 주지 못하고 있다. 이에 본 연구는 실험실 내 데이터 처리 및 통합 관리 역할을 해온 LIMS(Laboratory Information Management System)를 활용하여 실험 데이터들로부터 실험 디자인을 위한 효율적이고 효과적인 형식지(Explicit Knowledge)의 생성을 목적으로 하는 지식 생성 툴(Knowledge Creation Tool)을 설계하였다. 또한 상기 모델을 적용하여 실제 어떠한 형태로 지식이 생성되는지 A대학교 B유전자 연구실의 실험 데이터로 실증 분석해 보았다.

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