• 한국응용과학기술학회지
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• 제14권3호
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• pp.55-61
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• 1997

Maxwell displacement current(MDC) measuring technique has been applied on the study of monolayers of polyamic acid containing p-cyanoazobenzene. The displacement current was generated from monolayers on the water surface by monolayer compression and expansion. Displacement current was generated when the area per molecule was about $140{\AA}^2$ and $100{\AA}^2$. Maxwell displacement currents were investigated in connection with monolayer compression cycles. It was found that the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles.

• 한국응용과학기술학회지
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• 제14권2호
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• pp.35-40
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• 1997

The organization of phospholipid monolayers and their monolayers mixed with fatty acid containing azobenzene on the water surface was investigated by means of the displacement current measurement method. The phase transition from the gaseous phase to the gaseous-fluid phase which accompanies the polar ordering of phospholipid molecules was detected in the range of immeasurably low surface pressure. The molecular area which gives the onset of the transition was determined for phospholipid monolayers. The Maxwell displacement current(MDC) pulses were generated across mixed monolayers due to the photoisomerization of fatty acid containing azobenzene by alternating irradiation of ultraviolet and visible light, because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipids into the monolayers. The displacement currents generated during light irradiation were also investgated in connection with monolayer compression cycles. It was found that the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles.

• 한국응용과학기술학회지
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• 제28권2호
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• pp.213-218
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• 2011

Displacement current measuring technique has been applied on the study of polyamic acid monolayer containing p-nitroazobenzene. The displacement current was generated from monolayer on the water surface by monolayer compression and expansion. Maxwell displacement current(MDC) was generated when the area per molecule was about $200{\AA}^2$ and $70{\AA}^2$. Maxwell displacement currents were investigated in connection with monolayer compression cycles. It was found that the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles. The monolayer surface morphology of the LB film have been measured by Atomic Force Microscope(AFM). As a result, we confirmed that the microscopic properties of LB film by AFM showed the good orientation of monolayer molecules and the thickness of monolayer was 3.5-4.1nm.

• 한국광학회지
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• 제8권3호
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• pp.199-203
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• 1997

안구표면과 같은 미세구면의 변위를 알아내기 위하여 Twyman-Green 간섭계를 이용하였으며 반송무늬(carrier fringe)를 형성시켜 푸리에 변환법으로 미세구면의 변위분포를 측정하였다. 기준위치에서 일정한 반송무늬가 형성되도록 한 후 구면이 변화할 때 반송무늬의 변화방향을 관측하였으며, 반송무늬의 변화방향에 의해 구면의 변화방향을 알아내었다. 푸리에 변환법(Fourier transform method)을 이용하여 CCD카메라에서 받아들여진 한 장의 간섭무늬로부터 위상분포를 얻어내고 구면의 변위 분포를 계산하였다. 공간주파수 영역에서 변위에 대한 정보를 분리함으로써 간섭무늬의 배경분포 및 잡음을 제거하였으며, 구면의 변위에 대한 3차원 분포를 이론적인 계산값의 측정오차가 .lambda./10 이내에서 얻어내었다.

• 한국자동차공학회논문집
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• 제1권2호
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• pp.125-133
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• 1993

Electronic Speckle Pattern Interferometry(ESPI) using a CW laser, a video system and image processor was applied to the rotating displacement of rigid body. ESPI require no special surface preparation or attachments and displacements between any two arbitrary points on the surface can be measured. The characteristic speckle pattern formed when imaging a scattering surface illuminated by laser light retains phase information, which can be used for interferometric measurement of surface displacement. The application of this principle to measuring in-plane displacement resolved in one direction is described, together with the novel use of television equipment to detect and process the information contained in the speckle pattern. This is faster, and more convenient and versatile than customary photographic methods.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.351-352
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• 2010

• 한국지반공학회논문집
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• 제19권4호
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• pp.23-32
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• 2003

사면지반변위를 측정하기 위한 기존의 시스템은 고가의 장비를 사용함에도 불구하고 설치ㆍ유지가 힘들고 지반지표의 전반적 계측이 힘들며 계측시 위험을 항상 동반한다. 따라서, 이러한 단점을 극복하고 사면의 변위량을 굴착초기부터 굴착단계별 및 유지관리단계까지 쉽게 미숙련자들도 측정할 수 있는 방법이 필요하며 이를 위하여 사진측량 장점을 활용한 소프트카피 사진측량(Softcopy Photogrammetry)의 매카니즘이 사면지반의 변위계측을 위해 적용되었으며 이는 접근하기 어려운 위험 사면의 3차원 지반데이터를 효과적으로 획득ㆍ분석할 수 있는 방법으로 제시하였다. 또한, 기존의 지상사진측량결과 분석과는 다른 등고선 재생성과정을 광속조정프로그램인 DIMA (Digital IMage Analysis)를 개발 적용하여 적용성을 높였다. 사면파괴발생현장 사례를 통해 사면파괴 전후의 계측결과에 대한 사면안정체계 및 기존계측시스템의 단점을 해결할 수 있는 기술적 토대를 마련할 수 있었다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제33회 KOSCO SYMPOSIUM 논문집
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• pp.177-186
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• 2006

Flame surface area is a critical parameter determining turbulent flame speed. Three-dimensionaldirect numerical simulations (DNS) were conducted to figure out the evolution process of flame surface area. Fully compressible Navier-Stokes equations are solved to reproduce premixed flame embedded in isotropic decaying turbulent flow. The tangential straining and curvature of propagating surface affect development of flame area. In this study, four different turbulent intensity flows and three different Le number flames are investigated to force changes in straining and curvature effects. Consistent results are obtained for the probability density functions (PDF) of strain and curvature with previous researches. It is revealed that displacement speed, which is a speed of flame surface relative to unburnt flow, controls the balance between sink and source of flame surface area.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.156-159
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• 2003

Surface normal vector and surface velocity are very important parameters to simulate rolling processes precisely. In this study, Local displacement functions are constructed for each node on the contact surface and parameters are found by the least square fitting of displacement on the neighbor nodes. Deformation gradient tensor is calculated from the displacement function and surface normal vector and velocity also can be derived. Flat rolling simulation model is presented on the basis of the suggested contact scheme. Series of rolling process simulation are carried out and the results are compared with the experiments.

• 한국연소학회지
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• 제12권2호
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• pp.10-19
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• 2007

Flame surface area is a critical parameter determining turbulent flame speed. Three-dimensional direct numerical simulations(DNS) were conducted to figure out the evolution process of flame surface area. Fully compressible Navier-Stokes equations are solved to reproduce premixed flame embedded in isotropic decaying turbulent flow. The tangential straining and curvature of propagating surface affect development of flame area. In this study, four different turbulent intensity flows and three different Le number flames are investigated to force changes in straining and curvature effects. Consistent results are obtained for the probability density functions (PDF) of strain and curvature with previous researches. It is revealed that displacement speed, which is a speed of flame surface relative to unburnt flow, controls the balance between sink and source of flame surface area.