• Title/Summary/Keyword: laser Doppler

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An Analysis and a 3D Prediction of vibration modes in a Laser Doppler (레이저 도플러의 진동에 대한 분석과 3차원 예측연구)

  • Baik, Ran
    • Journal of Digital Contents Society
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    • v.11 no.2
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    • pp.117-122
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    • 2010
  • This is a study on the analysis of vibration mode of a laser doppler. We measure the vibration mode of a doppler and analyze each component, and want to estimate three dimensional properties from 2-dimensional data. The vibration mode relies on a range detector that uses a distance sensor. Since the outputs are determined by the measured distance, we want to study how 3-dimensional vibration mode is generated from 2-dimensional ones. The study will include the patterns of generating a 3-dimensional vibration mode as well as the relationship between the distance and the vibration mode.

Relationship between UV-induced MED and Perfusion Value Assessed by Laser Doppler Perfusion Imager (Laser Doppler Perfusion Imager (LDPI)로 측정한 자외선 조사부위의 혈류량과 최소 홍반량(MED)과의 상관관계)

  • Kim, Nam-Soo;Lee, Kyung-Hoon
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.31 no.3 s.52
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    • pp.259-263
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    • 2005
  • The aim of the present study is to evaluate relationship between UV-induced MED and perfusion value assessed by Laser Doppler Perfusion Imager. In this study, A increasing linear relationship is seen between perfusion and dose (p<0.05). The dose-response curve show a steep slope in the case of lower MED values group after MED point, For higher MED group, increase with a gentle slope.

Determination of Flow Direction by Using an Acousto-Optic Effect (광음향 변조효과를 이용한 유체의 방향 결정)

  • 김규욱
    • Proceedings of the Optical Society of Korea Conference
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    • 1990.02a
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    • pp.34-36
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    • 1990
  • The flow direction in a glass tube is measured by using a forward scatering dual beam laser Doppler velocimeter with an acousto-optic modulator. We can determine the flow direction by measuring the shifted Doppler frequency which is dependent on the order of modulation of the laser frequency shifting moves only the Doppler signal, enabling complete separation of the Pedestal and Doppler singal.

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THE USE OF LASER DOPPLER FLOWMETER FOR PULP VITALITY TEST (치수생활력 검사를 위한 Laser Doppler Flowmeter의 이용)

  • Su, Wan-Jong;Kim, Hyun-Jung;Nam, Soon-Hyeun;Kim, Young-Jin
    • Journal of the korean academy of Pediatric Dentistry
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    • v.25 no.3
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    • pp.562-568
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    • 1998
  • Various diagnostic methods, such as electric pulp test, cold test, test cavity etc., have been used to determine the pulp vitality. At least two or more methods should be used with supplemental information to diagnose each case because using one method doesn't provide sufficient accuracy. These conventional methods have depended on nervous responses, but Laser Doppler Flowmeter determines the pulp vitality by measuring pulpal blood flow. In this case, we tested the vitality of the traumatized teeth with incomplete root apices and autotransplanted teeth with conventional methods and Laser Doppler Flowmeter. Conventional methods, such as electric pulp test and cold test can produce various responses according to the development state of the pulpal nerve and the sensory threshold of the patient. But, Laser Doppler Flowmeter has a lower false response rate than any other pulp vitality test methods and it can determine the vitality somewhat earlier than the other method.

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PULP VITALITY TEST OF TEETH AFTER TRAUMATIC INJURIES USING LASER DOPPLER FLOWMETRY - A CASE REPORT (외상 받은 치아의 치수생활력 검사 - Laser Doppler flowmetry를 이용한 증례보고)

  • Song, Yun-Ju;Kim, Hyun-Jung;Nam, Soon-Hyeun;Kim, Young-Jin
    • Journal of the korean academy of Pediatric Dentistry
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    • v.26 no.2
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    • pp.310-316
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    • 1999
  • In the traumatized teeth, the major complications are pulp necrosis, and root resorption. The factors influencing to prognosis are the state of root development, type of injuries, quality of fixation. There are good prognosis in the case of immature teeth, minor luxation injuries. To minimize of occurrence of these complication, it is very important to determine the pulp vitality. This can help us decide whether or not to treat the teeth endodontically. But, it is difficult to determine of pulp vitality in immature teeth or traumatized teeth. In this case, pulp vitality test was done periodically on the traumatized upper central incisors, and the results were different among cold test, electric pulp test, and laser Doppler flowmetry. The conclusions were obtained from this case can be summarized as follows; 1. Pulp vitality of traumatized teeth should be negative early, but with time going, pulp vitality could be recovered. 2. The positive response of pulp vitality test was detected earlier in laser Doppler flowmetry. 3. Between cold test and electric pulp test, cold test was more reliable in determining pulp vitality.

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A Continuous Scanning Laser Doppler Vibrometer for Mode Shape Analysis (모드형상분석을 위한 연속 스캐닝 레이저 도플러 진동측정기)

  • Park, Kyi-Hwan;Choi, Ji-Eun;La, Jong-Pil;Wang, Sem-Yung;Kyoung, Yong-Soo;Kim, Koung-Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.5
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    • pp.734-741
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    • 2003
  • This paper addresses the vibration mode shape Measurement technique utilizing a Continuous Scanning Laser Doppler Vibrometer (CSLDV). The continuous scanning capability is added to the conventional discrete Laser Doppler Vibrometer by reflecting the laser beams on the surface of the object using two oscillating mirrors. The bow scanning resulted from the proposed scanning method is eliminated by feedback control. The velocity output signal from the CSLDV is modulated to give the spatial velocity distribution in terms of coefficients which are obtained from the Fast Fourier Transformation of the time dependent velocity signal. Using the Chebyshev series from, the analysis of the vibration mode shape techniques for straight line scanning and 2 dimensional scanning are presented and discussed. The performance of the proposed SLDV is presented using the experimental results of the vibration mode shape of a cantilever and plate

The Research on the Vibration of the Circular Plate for Varying Free Arc Angles by Time-Average Holographic Interferometry (시간평균 홀로그래픽 간섭계를 이용한 경계조건의 변화에 따른 원형평판의 진동에 관한 연구)

  • 이기백;양장식;나종문
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.10
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    • pp.1900-1907
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    • 1992
  • This paper presents the vibration mode, natural frequencies and amplitudes of the circular plate due to the changes of the boundary conditions by varying free arc angles. The vibration mode, amplitudes and natural frequencies of the circular plate are obtained by time-average holographic interferometry and laser doppler vibrometer. The vibration modes of the circular plate with the mixed boundary conditions are found from the 1st mode to the 4th mode. The curve shapes of the natural frequency ratios obtained from this study are in a good agreement with other results obtained by numerical analysis. The displacement curves obtained from time average holographic interferometry and laser doppler vibrometer agree well in case of large amplitude, but show a little difference in case of small amplitude.