• Title/Summary/Keyword: Collimated Beam

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The Analysis on the Error of Diverging Beam and Cylindrical Surface in Holographic Interferometer for Measuring out-of-plane Displacement. (면외변위 측정을 위한 홀로그래피 간섭게에서 발산빔과 원통표면에 대한 오차해석)

  • Kang, Young-June;Moon, Sang-Joon
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.6
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    • pp.128-134
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    • 1997
  • Holographic interferometry is a useful whole-field nondestructive tesing method for measuring deformations and vibrations of engineering structure. In practical way most holographic interferometer uses a diverging beam, a point light source. When an oject is relatively small, the optical arrangement using a collimated light source has no difficulty technically but for a large object the collimated beam connot be applied anymore practically. In this paper we calculate the error of measured displacement from the sensi- tivity vector dominated by the geometry of optical arrangement for holographic interferometer and show the result with 2-D plots. A plane surface and a cylindrical surface were chosen as objects to be measured and the results from the cases of a diverging and a collimated beams were compared and analyzed.

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Transient Radiative Heat Transfer Using Finite Volume Method with 2-Order Upwind Scheme and QUICK Scheme (비정상상태 복사열전달 해석을 위한 2 차 상류스킴 및 QUICK 스킴의 유한체적복사해법 적용 연구)

  • Byun, Do-Young;Lee, Gun-Ho;Kim, Man-Young
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1294-1299
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    • 2004
  • Transient radiative heat transfer is analyzed in a one-dimensional slab using finite volume method (FVM). In this study, the step, $2^{nd}$ order upwind, and QUICK schemes are used for incident diffuse radiation and collimated beam, respectively. The results for diffuse radiation show that all schemes applied in this study give good agreements with available published results. In case of collimated beam, however, the results show deviations from the analytical solutions. To successfully describe the propagations of collimated beam, shock capturing schemes such as TVD scheme are need to be developed.

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Analysis on the error of sensitivity vector of holographic interferometer for measuring out-of-plane displacement (면외변위 측정을 위한 홀로그래픽 간섭계의 민감도백터의 오차 해석)

  • 문상준;강영준;백성훈;김철중
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.515-518
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    • 1994
  • Holographic interferometry is a useful whole-field nondestructive testing for measuring deformations and vibrations of engineering structure. A diverging beam is used as a light source int the most of holographic interferometer practically. For a relatively small object the optical arrangement using a collimated light source has no difficulty in use technically, but for a large object it is difficult to use a collimated beam. In this study we calculate the error of measured displacement from the sensitivity vector dominated by the geometry of optical arrangement for holographic interferometer and show the result obtained with 2-D plots. A Plane surface and a cylindrical surface were chosen as objects to be calculated and computer analysis was carried out for the cases of a diverging beam and a collimated one.

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1- Dimensional Transient Radiative Heat Transfer Using Finite Volume Method with 2-Order Upwind Scheme and QUICK Scheme (1차원 비정상상해 복사열전달 해석을 위한 2차 상류스킴 및 QUICK 스킴의 유한체적복사해법 적용 연구)

  • Lee Gun-Ho;Kim Man-Young;Byun Do-Young
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.3 s.246
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    • pp.201-207
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    • 2006
  • Transient radiative heat transfer is analyzed in a one-dimensional slab using finite volume method (FVM). In this study, the step, $2^{nd}$ order upwind, and QUICK schemes are used for incident diffuse radiation and collimated beam, respectively. The results fer diffuse radiation show that all schemes applied in this study give good agreements with available published results. In case of collimated beam however, the results show deviations from the analytical solutions. To successfully describe the propagations of collimated beam shock capturing schemes such as TVD scheme are need to be developed.

A Study of the Dependence on Incidence Angle of the Sensitivity of an Extraordinary Optical Transmission Sensor (특이 광 투과 센서에서 민감도의 입사각 의존성 연구)

  • Kwon, Yongjae;Lee, Seunghun;Kim, Taeyeon;Kim, Kyujung
    • Korean Journal of Optics and Photonics
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    • v.32 no.3
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    • pp.126-132
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    • 2021
  • In this research, we have investigated the sensitivity of an extraordinary optical transmission sensor depending on the angle of incident light. Three types of light, including a collimated beam and focused beams (4× and 10×), were designed for the sensor system. To compare the sensitivity of the sensor, we measured transmittance spectra using deionized water (n=1.333) and refractive-index-matching oils (n=1.360 and 1.380). Those spectra were analyzed in terms of redshifting of the peak, so that we could determine the sensitivity. The sensitivity tended to increase when the collimated beam is used on the system, and we have concluded that the sensitivity could be affected by the incidence angle on an extraordinary optical transmission sensor.

Study of ion beam shaping of an anode-type ion source coupled with a Whenelt mask

  • Huh, Yunsung;Hwang, Yunseok;Kim, Jeha
    • Applied Science and Convergence Technology
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    • v.27 no.4
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    • pp.70-74
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    • 2018
  • We fabricated an anode-type ion source driven by a charge repulsion mechanism and investigated its beam shape controlled by a Whenelt mask integrated at the front face of the source. The ion beam shape was observed to vary by changing the geometry of the Whenelt mask. As the angle of inclination of the Whenelt mask was varied from $40^{\circ}$ to $60^{\circ}$, the etched area at a thin film was reduced from 20 mm to 7.5 mm at the working distance of 286 mm, and the light transmittance through the etched surface was increased from 78% to 80%, respectively. In addition, for the step height difference, ${\Delta}$ between the inner mask and the outer mask of ${\Delta}=0$, -1 mm, and +1 mm, we observed the ion beam shape was formed to be collimated, diverged, and focused, respectively. The focal length of the focused beam was 269 mm. We approved experimentally a simple way of controlling the electric field of the ion beam by changing the geometry of the Whenelt mask such that the initial direction of the ion beam in the plasma region was manipulated effectively.

Study on terrestrial LIDAR transmitter designed to improve accuracy (측량용 레이저 스캐너의 정밀도 개선을 위한 송신부설계)

  • Yoo, Hyun-Kuk;Jeong, Jung-Yeon;Oh, Dong-Geun;Kim, Jae-Soon
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2009.04a
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    • pp.41-48
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    • 2009
  • Laser diode is used as a crucial part for minimization of terrestrial 3D Laser Scanner. But it has certain limitations such as oval beam shape and inevitable astigmatism. In order to realize a parallel light with beam divergence below 1 mrad, These problems of laser diode can be solved through beam shaping by Pinhole and Aperture. Finally, this study could materialize a collimated beam with 0.3 mrad beam divergence angle and 3mm diameter, that performance and checked by using real manufacture.

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Collimation of cesium atomic beam using laser light pressure (레이저 광압을 이용한 세슘 원자빔의 집속)

  • 박상언
    • Korean Journal of Optics and Photonics
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    • v.11 no.4
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    • pp.227-231
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    • 2000
  • Thermal cesium atomic beam was collimated by transversely cooling of atoms, for which circularly polarized ($\sigma^+$ and $\sigma^-$ polarized) laser light was illuminated to the atomic beam from two perpendicular directions. As a result, the temperature corresponding to the transverse velocity component could be decreased from 430 mK to 60 11K. In addition, the spatial atomic distribution was observed according to the power difference of the two laser beams and the magnetic field applied, and the result was qualitatively coincided with the calculation result by the Doppler cooling theory. heory.

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Measurement of Temperature Field using Holographic and Speckle Visualization Techniques (홀로그래피/스페클 가시화를 이용한 온도분포 측정)

  • 백성훈;박승규;김철중
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.371-374
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    • 1995
  • The real-time holographic interferometer with a digital high-speed camera is applied to the visualization of transient temperature field. Collimated and diffused laser beams are used to the object beam according to the shape and transmittance of the phase object. Also, ESPI(Electronic Speckle Speckle Pattern Interferometer) technique is used to the visualization and quantitatie measurement of slow-varying temperature field. The experimental results obtained form these two techniques are discussed.

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