• 제목/요약/키워드: surface front

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액체와 2 파장 투과형 편향법을 이용한 다초점 렌즈 양면 프로파일 동시측정 (Simultaneous Determination of Both Surface Profiles of a Bifocal Lens Using Dual-Wavelength Transmission Deflectometry With Liquid)

  • 신상훈;유영훈
    • 한국광학회지
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    • 제26권3호
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    • pp.147-154
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    • 2015
  • 두 개의 액체와 두 개의 파장을 이용한 투과형 편향법을 이용하여 시료 양면의 3차원 형상을 동시에 측정 할 수 있는 모델을 제시하고, 실험적으로 다초점 렌즈의 양면 프로파일을 측정하였다. 편향법은 면적이 비교적 크고 거울과 같이 산란이 거의 없는 물체의 3차원 측정을 하는데 유용하다. 편향법을 통해 얻은 왜곡 무늬로부터 위상 기울기를 구하기 위해 위상이동법과 시간추적 위상펼침 (TPU:Temporal Phase Unwrapping) 방법을 이용하였고, 구한 기울기로부터 3차원 프로파일을 구하기 위해 최소자승법을 이용하였다. 본 연구에 사용된 방법은 기존의 투과형 편향법과는 달리 시료의 이동 없이 동시에 양면 프로파일을 측정할 수 있는 장점이 있다.

형상충전기법과 세분화된 유동장 재생성기법을 이용한 자유표면을 가진 비압축성 점성유동의 수치적 모사 (Numerical Analysis of Incompressible Viscous Flow with Free Surface Using Pattern Filling and Refined Flow Field Regeneration Techniques)

  • 정준호;양동렬
    • 대한기계학회논문집A
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    • 제20권3호
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    • pp.933-944
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    • 1996
  • In this paper, two new techniques, the pattern filling and the refined flow field regeneration, based on the finite element method and Eulerian mesh advancement approach have been developed to analyze incompressible viscous flow with free surfaces. The gorerning equation for flow analysis is Navier-Stokes equation including inertia and gravity effects. The penalty and Newton-Raphson methods are used effectively for finite element formulation. The flow front surface and the volume inflow rate are calculated using the pattern filling technique to select an adequate pattern among five filling patterns at each quadrilateral control volume. By the refined flow field regeneration technique, the new flow field which renders better prediction in flow surface shape is generated and the velocity field at the flow front part is calculated more exactly. Using the new thchniques to be developed, the dam-breaking problem has been analyzed to predict flow phenomenon of fluid and the predicted front positions versus time have been compared with the reported experimental result.

삼각형 요소의 형상 충전 및 격자 세분화를 이용한 붕괴하는 물 댐의 유한 요소 해석 (Finite Element Analysis of Collapse of a Water Dam Using Filling Pattern Technique and Adaptive Grid Refinement of Triangular Elements)

  • 김기돈;양동열;정준호
    • 대한기계학회논문집B
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    • 제28권4호
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    • pp.395-405
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    • 2004
  • The filling pattern and an adaptive grid refinement based on the finite element method and Eulerian mesh advancement approach have been developed to analyze incompressible transient viscous flow with free surfaces. The governing equation for flow analysis is Navier-Stokes equation including inertia and gravity effects. The mixed FE formulation and predictor-corrector method are used effectively for unsteady numerical simulation. The flow front surface and the volume inflow rate are calculated using the filling pattern technique to select an adequate pattern among four filling patterns at each triangular control volume. By adaptive grid refinement, the new flow field that renders better prediction in flow surface shape is generated and the velocity field at the flow front part is calculated more exactly. In this domain the elements in the surface region are made finer than those in the remaining regions for more efficient computation. Using the proposed numerical technique, the collapse of a water dam has been analyzed to predict flow phenomenon of fluid and the predicted front positions with respect to time have been compared with the reported experimental results.

진동둘레선 설계를 위한 진동체표변화에 관한 연구 (Body Surface Changes at Armhole Area for the Pattern of Armhole Line)

  • 이정란;임원자
    • 한국의류학회지
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    • 제20권5호
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    • pp.930-942
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    • 1996
  • This study was done to provide the characteristics of body surface changes at armhole area. Experiments were carried out at upper arm and upper body inchuding 67 items, 74 segments by the stanard posture and arm movements. The subjects were 15 females of twenty aged. The major conclusions of this study are; 1. On the circumference items of upper arm, armhole circumference was decreased by all arm movement, especially high contracted on front armhole line. The most contracted segments of armhole circumference were from the shonlder point to front and back interscye breadth point. Axillary circumference was increased 5 cm to the utmost, so the function of sleeve pattern would be decided by axillary circumference. 2. The lengths of upper arm were decreased near center line, sleeve cap length was contracted 3∼4 cm. Posterior armpit point area was increased both length and breadth. According to the rates of expansion and contraction, the diagram of expansion and contraction of upper arm was suggested. 3. On upper body, back side chest breadth was increased exceedingly and shoulder length was decreased most. It was apparent that surface changes of upper body were greatly larger as far away from center front and center back line. The rates of expansion and contraction of upper body were also represented as a diagram of surface changes.

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Slacks의 기능성에 관한 인간공학적 연구 -동하부 및 대퇴부의 신축을 중심으로- (An ergonomic Study on the function of Slacks -On the Expansion and Contraction of the Skin Surface of the Lower Body-)

  • 함옥상
    • 대한가정학회지
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    • 제19권2호
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    • pp.151-163
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    • 1981
  • This study was to investigate the changes of shape of the surface square measurements, the rate, measurements of expansion and contraction and correlation. In this study was found the following: 1. According to the developmental illustration of the shell it was revealed that there was a great change in the thigh area of the body. When the leg was raised and the waist bent forward the front sections of the abdomen were contracted and the center back of the hip was expanded. 2. It was found that the contraction was present in the girth of the back section and front section was expanded in the rate of the body surface. In the length from the middle waist to hip the front area showed a great deal of contraction the back area of the hip & thigh revealed a great deal of expansion. 3. By the somatometry, the measurements of the expansion and contraction of the body surface, there was a great change in waist and hip. It revealed that the maximum expansions of waist and hip line in the chair were 1.8cm and 4.08cm respectively. Therefor, when slacks are made at least the amount of ease of 1.8cm of waist line and 4cm of hip line must be made and the allowance of the center back of hip area must be made. 4. It revealed that there was a correlation between waist and hip girth.

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Conditions for No Soil -Push By Outside of Front Cutting Surface on Bent Blade

  • Chen, Cuiying;Mao, Hanping
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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    • pp.1088-1094
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    • 1993
  • One of the important restraint conditions for determination of rotary tiller parameters is whether the outside of front cutting surface on blade in rotary tiller pushes untilled soil in operation. By theoretical analysis and graphic verification on computer, no sil-push conditions is put forward and formula for calculating the position angle of its bent line derived, as is convenient for selection of rotary tiller parameters and design and drawing of its blade.

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Bare Wafer Inspection using a Knife-edge Test

  • Lee, Jun-Ho;Kim, Yong-Min;Kim, Jin-Seob;Yoo, Yeong-Eun
    • Journal of the Optical Society of Korea
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    • 제11권4호
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    • pp.173-176
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    • 2007
  • We present a very simple and efficient bare-wafer inspection method using a knife-edge test. The wafer front surface and inner structures are inspected simultaneously. The wafer front surface is inspected visually using a knife-edge test while the inner structure is simultaneously inspected by a camera in the infrared region with a single white-light source. This paper presents a laboratory implementation of the test method with some experimental results.

Unstructured Quadrilateral Surface Grid Generation and Cell Size Control

  • Kim, Byoung-Soo
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2008년도 학술대회
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    • pp.386-389
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    • 2008
  • In this paper grid generation of unstructured quadrilateral surface grids is described. The current approach uses conventional Advancing Front Method which is used to generate unstructured triangular grids. Grid cell size control is done by using closeness-based global interpolation method controlled by pre-described control elements. Algorithm and procedure for quadrilateral grid generation using AFM method and cell size control method are described. Examples of quadrilateral grid generation are shown, and difficulties and problems related to the current approach are also discussed.

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Unstructured Quadrilateral Surface Grid Generation and Cell Size Control

  • Kim, Byoung-Soo
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2008년 추계학술대회논문집
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    • pp.386-389
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    • 2008
  • In this paper grid generation of unstructured quadrilateral surface grids is described. The current approach uses conventional Advancing Front Method which is used to generate unstructured triangular grids. Grid cell size control is done by using closeness-based global interpolation method controlled by pre-described control elements. Algorithm and procedure for quadrilateral grid generation using AFM method and cell size control method are described. Examples of quadrilateral grid generation are shown, and difficulties and problems related to the current approach are also discussed.

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