• Title/Summary/Keyword: LIF

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At the time of issuing the Journal of Korean Life Insurance Medical Association volume 27(1) (보험의학회지 제27권 1호의 발간에 즈음하여...)

  • Lee, Sin-Hyung
    • The Journal of the Korean life insurance medical association
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    • v.27 no.1
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    • pp.6-8
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    • 2008
  • Korean life insurance medical association's public periodical, the Journal of Korean Life Insurance Medical association (J Kor Lif Ins Med Assoc, JKLIMA) is now published $27^{th}$ issue. From this issue there are some changes of the journal than before. It is because general requirements for medical journals from the Korean association of medical journals editors. It can be remedy for the development of JKLIMA, in terms of academicism. First, the style of the manuscripts, medical opinion of insurance administration is added. This style of manuscript needs not keep the format of original research article such as background, materials, results, and discussion. Secondly, It is emphasized that submitted manuscripts must be reviewed by peer reviewers. Thirdly, we will make an effort to globalization of our journal. Lastly the publication period has been changed from annual to biannual. The publication date will be at March 31st and September 30th every year.

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An Experimental Study on the Lift-off Characteristics of the Triple Flame with Concentration Gradient (농도구배가 삼지화염의 부상특성에 미치는 영향에 관한 실험적 연구)

  • Seo, Jeong-Il;Kim, Nam-Il;Oh, Kwang-Chul;Shin, Hyun-Dong
    • 한국연소학회:학술대회논문집
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    • 2004.06a
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    • pp.7-14
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    • 2004
  • The lift-off characteristics of the triple flame have been studied experimentally with various mean velocities and concentration gradients using a multi-slot burner, which can control the concentration gradient and the mean velocity independently, Lift-off height, axial maximum velocity, flame temperature, and some other characteristics were examined for methane and propane flame, It was found that minimum values of the lift-off heights exist at a certain concentration gradient for constant mean velocity, and this result implies that the propagation velocity has a maximum value at this condition, OH radical distribution was measured with LIF method and velocity variation along streamline was measured with PlV system. In addition maximum temperature along streamline was measured with CARS system. The intensity of the diffusion flame affects on the propagation velocity of triple flame in the region of very weak concentration gradient.

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A Study on the Algorithm for Fault Discrimination in Transmission Lines using Neural Network and the Variation of Fault Currents (신경회로망과 고장전류의 변화를 이용한 고장판별 알고리즘에 관한 연구)

  • Yeo, Sang-Min;Kim, Cheol-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.49 no.8
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    • pp.405-411
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    • 2000
  • When faults occur in transmission lines, the classification of faults is very important. If the fault is HIF(High Impedance Fault), it cannot be detected or removed by conventional overcurrent relays (OCRs), and results in fire hazards and causes damages in electrical equipment or personal threat. The fast discrimination of fault needs to effective protection and treatment and is important problem for power system protection. This paper propolsed the fault detection and discrimination algorithm for LIFs(Low Impedance Faults) and HIFs(High Impedance Faults). This algorithm uses artificial neural networks and variation of 3-phase maximum currents per period while faults. A double lines-to-ground and line-to-line faults can be detected using Neural Network. Also, the other faults can be detected using the value of variation of maximum current. Test results show that the proposed algorithms discriminate LIFs and HIFs accurately within a half cycle.

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Study on Instantaneous Structure of Turbulent Pulverized Coal Flame by Simultaneous Measurement (동시계측에 의한 난류 미분탄 화염의 순간구조에 관한 연구)

  • Hwang, Seung-min
    • Journal of Environmental Science International
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    • v.27 no.5
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    • pp.309-317
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    • 2018
  • In this study, a laser sheet technique and PLIF (Planar laser-induced fluorescence) are applied to a laboratory-scale pulverized coal burner of the open type, and the spatial relationship of the pulverized coal particle zone and the combustion reaction zone is examined by simultaneous measurement of Mie scattering and OH-LIF images. It is found that this technique can be used to investigate the spatial relationship of the combustion reaction zone and pulverized-coal particles in turbulent pulverized-coal flames without disturbing the combustion reaction field. In the upstream region, the combustion reaction occurs only in the periphery of the clusters where high-temperature burned gas of the methane pilot flame is entrained and oxygen supply is sufficient. In the downstream region, however, combustion reaction can be seen also within clusters of pulverized-coal particles, since the temperature of pulverized-coal particles rises, and the mixing with emitted volatile matter and ambient air is promoted.

On the adaptive pre-processing technique for the linerization of weakly nonlinear volterra systems (볼테라 시스템 선형화를 위한 적응 선행처리 기법)

  • Choi, Bong-Joon;Kim, Yong-Nam;Chung, Ji-Hyun;Nam, Sang-Won
    • Journal of Institute of Control, Robotics and Systems
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    • v.3 no.5
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    • pp.450-454
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    • 1997
  • 본 논문에서는 볼테라 비선형 시스템의 선형화를 위한 새로운 적응 선행처리 기법을 제시한다. 특히, 제안된 적응 선행처리 기법은 (i) 순수 비선형 왜곡 보상을 위한 부분(pure nonlinear distortion compensator: PNDC)과, (ii) 선형 왜곡 보상을 위한 선형 역필터(linear inverse filter: LIF)의 두 부분으로 구성된다. 본 논문의 선형화 기법의 장점으로는 기존의 P차 역(Pth-order inverse) 기법에 비하여 계산량이 상당히 감소되며, 적응 알고리듬이 보다 빠르고 안정된 수렴 특성을 나타낸다. 끝으로, 모의실험을 통하여, 제안된 선행처리 기법의 성능및 실제 적용 가능성을 살펴본다.

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Application of Fluorescence/Scattering Technique to the Measurement of Spray Droplet Size in GDI Injector (직접 분사식 가솔린 인젝터 분무의 입경 측정에 형광/산란광법의 적용)

  • Kwak, Soo-Min;Ryu, Kyeong-Hun;Choi, Bong-Seok;Kim, Duck-Jool
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.353-358
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    • 2000
  • To achieve the requirement for high fuel economy and low emissions, the research for GDI engines is recently very brisk in the whole world. This study was performed to measure distribution of average particle size in non-evaporating spray. The 2-D fluorescence/scattering images of fuel spray were captured simultaneously by visualization system composed of a laser sheet, a doubling prism, optical filters, and an ICCD camera. Using the ratio of the two light intensities, particle size distribution was obtained. The SMD measured by fluorescence/scattering technique was compared with it obtained by PDA. The experimental results show that the spray structure of GDI injector and temporal SMD distribution.

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The Effects of Surface Shear Viscosity and Surface Tension on a Columnar Vortex Interacting with a Free Surface (자유표면과 반응하는 수직와류에 대한 표면점성계수와 표면장력의 영향)

  • Kim Kyung-Hoon;Sohn Kwon;Kim Seok-Woo
    • Journal of the Korean Society of Visualization
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    • v.3 no.1
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    • pp.51-57
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    • 2005
  • Vertices terminating at free surface have been investigated extensively. Most of investigations, however, are focused on surface parallel vortices and little has been known about surface normal vortex or columnar vortex. Visualized experimental results utilizing LIF technique are discussed fur the purpose of characterization of columnar vortex interacting with a clean and a contaminated free surfaces and a solid body interface in the present investigation. The results reveal that surface tension changes due to surface contamination although bulk viscosity remains constant and eventually the behavior of a columnar vortex interacting with a contaminated free surface and a solid body interface are totally different from the clean free surface case.

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A Study on the baffle effect in a stirred mixer using simultaneous measurement of velocity/concentration fields (속도/농도 동시측정에 의한 회전교반기 내부 유동의 baffle 효과에 관한 연구)

  • Kim Yun Gi;Min Young Uk;Kim Kyung Chun
    • 한국가시화정보학회:학술대회논문집
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    • 2003.11a
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    • pp.35-38
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    • 2003
  • Simultaneous measurement of velocity and concentration fields in a stirred mixer flow using a combined Stereo-PIV/Planar-LIF technique is carried out. Instantaneous velocity fields and concentration fields represent the local flow characteristics. A baffle is perpendicularly attached to the Wall to remove inactive region which shows very slow dispersion. It is found that the baffle produces tip vortex and breaking the divided streamline, so that mixing efficiency could be increases significantly.

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Flow Visualization in a new CSC micromixer (새로운 CSC micromixer 를 이용한 유동가시화)

  • Singh, Kanika;Kim, Hyun-Hoon;Min, Young-Uk;Kim, Hyung-Dong;Kim, Kyung-Chun
    • 한국가시화정보학회:학술대회논문집
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    • 2007.11a
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    • pp.63-65
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    • 2007
  • The paper reports on a new type of combinatorial chaotic and serpentine micromixer. Such a new and novel micromixer is simple to fabricate and easy to use. The micromixer is characterized and visualized with the help of the Micro-LIF technique. The new micromixer will e further applied to lab-on-chip device. The mixing capabilities of this mixer is about 30-33%.

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Study on the Fuel Vapor Distribution of the Stratified Charge in a DISI Engine by PLIF Technique (직분식 전기점화 엔진에서 PLIF기법에 의한 성층 혼합기의 분포특성 연구)

  • Kim, S.S.
    • Journal of Power System Engineering
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    • v.12 no.6
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    • pp.64-69
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    • 2008
  • The spatial fuel distribution of the stratified charge of a high pressure 6-hole injector was examined in a single cylinder optical direct injection spark ignition(DISI) engine. The effects of in-cylinder charge motion, and fuel injection pressure, and coolant temperature were investigated using a planar LIF(Laser Induced Fluorescence) technique. It was confirmed that the in-cylinder tumble flow played more effective role in the spatial fuel distribution of the stratified charge than the swirl flow during the compression stroke and the fuel distribution area increased due to the activation of the fuel vaporization by the increase of the coolant temperature. But, the increase of the fuel supplying pressure could not change the pattern of the fuel vapor distribution against the expectation.

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