• Title/Summary/Keyword: Two-dimensional probe

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A Handheld Probe Based Optical Coherence Tomography System for Diagnosis of Dental Calculus (치석 진단용 소형 프로브 기반 광간섭단층촬영 시스템)

  • Lee, Chang-Ho;Woo, Chai-Kyoung;Jung, Woong-Gyu;Kang, Hyun-Wook;Oh, Jung-Hwan;Kim, Jee-Hyun
    • Journal of Sensor Science and Technology
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    • v.21 no.3
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    • pp.217-222
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    • 2012
  • Optical coherence tomography(OCT) is a noninvasive optical imaging tool for biomedical applications. OCT can provide depth resolved two/three dimensional morphological images on biological samples. In this paper, we integrated an OCT system that was composed of an SLED(Superluminescent Light Emitting Diode, ${\lambda}_0$=1305 nm bandwith= 141 nm), a reference arm adopting a rapid scanning optical delay line(RSOD) to get high speed imaging, and a sample arm that used a micro electro mechanical systems(MEMS) scanning mirror. The sample arm contained a compact probe for imaging dental structures. The performance of the system was evaluated by imaging in-vivo human teeth with dental calculus, and the results indicated distinct appearance of dental calculus from enamel, gum or decayed teeth. The developed probe and system could successfully confirm the presence of dental calculus with a very high spatial resolution($6{\mu}m$).

An investigation on flow characteristics of two dimensional inclined wall attaching offset jet (단이 진 경사벽면에 부착되는 2차원 제트유동에 관한 연구)

  • 송흥복;심재경;윤순현
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.1
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    • pp.52-66
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    • 1998
  • An experimental study on the flow characteristics was performed for a two-dimensional turbulent wall attaching offset jet at different oblique angles to a surface. The flow characteristics were investigated by using a split film probe with the modified Stock's calibration method. The jet mean velocity, turbulent intensity, wall static pressure coefficient profiles, and time-averaged reattachment point were measured at the Reynolds number Re (based on the nozzle width, D) ranging from 17700 to 53200, the offset ratio H/D from 2.5 to 10, and the inclined angle .alpha. from 0.deg. C to 40.deg. C. The Correlations between the maximum pressure position, minimum pressure position, and reattachment point and offset ratios, and inclined angles are presented.

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Flexure hinge mechanism having amplified rectilinear motion for confocal scanning microscopy using optical section

  • Kwon, Oh-Kyu;Park, Poo-Gyeon
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.162.6-162
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    • 2001
  • Confocal scanning microscopy (CSM) is an important instrument in a wide variety of imaging applications because of its ability to provide three-dimensional images of thick, volume specimens. The mechanism for two-dimensional beam scanning and optical sectioning has an important roe in CSM as the three-dimensional profiler. This optical sectioning property arises from the use of a point detector, which serves to attenuate the signals from out-of-focus. The intensity profile for the open loop scanning should be matched with its response for the standard. The non-linearity can be minimized with the optical sectioning or the optical probe of the closed loop control. This paper shows the mathematical expression of the light such as the extinction curve in the optical fields of system using AO deflector, the axial/lateral response experimentally when the error sources change, and the methods of optical sectioning. Thorough design of optical sectioner is crucial to the success of CSM in the field ...

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Three-dimensional evaluation on the repeatability and reproducibility of dental scanner-based digital models (치과용 스캐너로 채득한 디지털 모형의 반복성 및 재현성에 관한 3차원적 평가)

  • Lee, Gyeong-Tak;Kim, Jae-Hong;Kim, Woong-Chul;Kim, Ji-Hwan
    • Journal of Technologic Dentistry
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    • v.34 no.3
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    • pp.213-220
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    • 2012
  • Purpose: The aim of this study was to determine the repeatability and reproducibility of two dental scanners. Methods: The master die and the stone replicas(Kavo, Germany) were digitized in touch-probe scanner(Incise, Renishaw, UK), white light scanner(Identica, Medit, Korea) to create 3-dimensional surface-models. The number of points in the point clouds from each reading were calculated and used as the CAD reference model(CRM). Discrepancies between the points in the 3-dimensional surface models and the corresponding CRM were measured by a matching-software(Power-Inspect R2, Delcam Plc, UK). The t-student test for one samples were used for statistical analysis. Results: The reproducibility of both scanner was within $3{\mu}m$, based on mean value. The mean value between measurements made directly on the touch probe scanner digital models and those made on the white light scanner digital models was $2.20-2.90{\mu}m$, and was statistically significant(P<0.05). Conclusion: With respect to adequate data acquisition, the reproducibility of dental scanner differs. Three-dimensional analysis can be applied to differential quality analysis of the manufacturing process as well as to evaluation of different analysis methods.

Microscopic Surface Dynamics Studied by Scanning Probe Microscopy

  • Gwon, Gi-Yeong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.111-111
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    • 2011
  • Arrangement of individual atoms and molecules with atomic precision and understanding the resulting properties at the molecular level are ultimate goals of chemistry, biology, and materials science. For the past three decades, scanning probe microscopy has made strides towards these goals through the direct observation of individual atoms and molecules, enabling the discovery of new and unexpected phenomena. This talk will discuss the origin of forces governing motion of small organic molecules and their extended self-assembly into two-dimensional surface structures by direct observation of individual molecules using scanning tunneling microscopy (STM). In addition, atomic force microscopy (AFM) is utilized for the investigation of fundamental mechanisms of bone mineral dissolution by examining atomically well characterized simulated bone minerals under aqueous solution environments.

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A Study on Smart Soil Resistance Measuring Device for Safety Characterized Ground Design in Converged Information Technology (ICT 융합 환경에서의 안전 특성화 접지 설계를 위한 스마트 대지 저항 측정 기술에 관한 연구)

  • Kim, Hong-Yong;Shin, Seung-Jung
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.19 no.1
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    • pp.203-209
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    • 2019
  • In this work, a new land-specific resistance measuring device (GM) and a measuring probe (Grounding Rod) are connected to the WENNER quadrant as power-line communication (PLC). In groups of two (P1,P2) probes, five to ten probes are installed in series on the ground at intervals of 1m, 2m, 4m, 8m, and 16m, respectively. If the PLC signal from the GMD is detected by the receiver of the Probe 1 (P1) for measurement, the minute voltage and current for measurement flow from the PSD (power supply) attached to the probe to the ground, and then, through the soil between P1 and P2, enters the Probe 1 (P2). The resistance value is then measured by the principle of voltage drop due to ground resistance. Measure the earth resistance every T seconds up to 1 trillion and store the measured data on the Arduino Server mounted on the main equipment. Stored measurement data can be derived from formulas by Ohm's Law and from inherent resistance (here,). Data obtained in real time will be linked to CDGES programs installed on Main PC, enabling data analysis and real-time monitoring of the ground environment on land. In addition, a three-dimensional display is possible with 3D graph support by identifying seasonal characteristics such as temperature and humidity of land (soils). The limitations of the study will require specific application measures of Test Bed for commercial access to a model that has been developed and operated experimentally.

Effect of Convex Wall Curvature on Three-Dimensional Behavior of Film Cooling Jet

  • Lee, Sang-Woo;Lee, Joon-Sik;Keon Kuk
    • Journal of Mechanical Science and Technology
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    • v.16 no.9
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    • pp.1121-1136
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    • 2002
  • The flow characteristics of film coolant issuing into turbulent boundary layer developing on a convex surface have been investigated by means of flow visualization and three-dimensional velocity measurement. The Schlieren optical system with a spark light source was adopted to visualize the jet trajectory injected at 35° and 90° inclination angles. A five-hole directional pressure probe was used to measure three-dimensional mean velocity components at the injection angle of 35°. Flow visualization shows that at the 90° injection, the jet flow is greatly changed near the jet exit due to strong interaction with the crossflow. On the other hand, the balance between radial pressure gradient and centrifugal force plays an important role to govern the jet flow at the 35° injection. The velocity measurement shows that at a velocity ratio of 0.5, the curvature stabilizes downstream flow, which results in weakening of the bound vortex structure. However, the injectant flow is separated from the convex wall gradually, and the bound vortex maintains its structure far downstream at a velocity ratio of 1.98 with two pairs of counter rotating vortices.

Three-Dimensional Flow and Aerodynamic Loss Downstream of a Turbine Rotor Blade with a Squealer Tip (스퀄러팁 터빈 동익 하류에서의 3차원 유동 및 압력손실)

  • Chae, Byoung-Joo;Lee, Sang-Woo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.9 s.252
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    • pp.913-920
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    • 2006
  • Three-dimensional flow and aerodynamic loss in the tip-leakage flow region of a high-turning first-stage turbine rotor blade with a squealer tip have been measured with a straight miniature five-hole probe for the tip gap-to-chord ratio, h/c, of 2.0%. This squealer tip has a indent-to-chord ratio, $h/{st}/c$, of 5.5%. The results are compared with those for a plane tip $(h_{st}/c=0.0%)$. The squealer tip tends to reduce the mass flow through the tip gap and to suppress the development of the tip-leakage vortex. Therefore, it delivers lower aerodynamic loss in the near-tip region than the plane tip does. At the mid-span, however, the aerodynamic loss has nearly the same value for the two different tips.

Simulation of Eddy Current Testing Signals Using Simulation Software Dedicated to Nondestructive Testing (비파괴검사 전용 시뮬레이터를 이용한 와전류검사 신호 시뮬레이션)

  • Lee, Tae-Hun;Cho, Chan-Hee;Lee, Hee-Jong
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.10 no.1
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    • pp.75-81
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    • 2014
  • A simulation of eddy current testing has been utilized for predicting the signal characteristics to the various defects and developing the probes. Especially, CIVA which is a simulation tool dedicated to nondestructive testing has a good accuracy and speed, and provides a three-dimensional graphical user interface for improved visualization and familiar data displays consistent with NDE technique. Although internal validations have been performed by the CIVA software development specialists, an independent validation study is necessary for the accuracy assessment of the software prior to practical use. For this purpose, in this study, eddy current testing signals of ASME FBH calibration standard tube for bobbin probe were simulated using CIVA and the results were compared to the experimental inspected signals based on the relationship between each flaw signal in terms of amplitude and phase, and the shape of the Lissajous curve. And then we verified the accuracy of the simulated signals and the possible range for simulation. Overall, there is a good qualitative agreement between the CIVA simulated and experimental results in the absolute and differential modes at the two inspection frequencies.

Performance Characteristics Due to the Inflow Distortion near Hub in an Axial Flow Fan (축류 송풍기 허브측 불균일 유입유동 현상 및 성능 특성)

  • Jang, Choon-Man;Choi, Seung-Man;Kim, Kwang-Yong
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.663-669
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    • 2005
  • Performance characteristics of an axial flow fan having distorted inlet flow have been investigated using numerical analysis as well as experiment. Two kinds of hub-cap, round shape and right-angled front shape, are tested to investigate the effect of inlet flow distortion on the fan performance. In case of right-angled front shape, axisymmetric distorted inflow is induced by flow separation at the sharp edge of hub-cap, and the characteristics of the inflow depends on the distance between hub-cap and blade leading edge. Flow analysis of the blade passage is peformed by solving the three-dimensional Reynolds-averaged Navier-Stokes equations. numerical solutions are validated in comparison with experimental data measured by a five-hole probe downstream of the fan rotor. It is found from the numerical results that non-uniform axial inlet velocity profile near the hub results in the change of inlet flowangle. The changed inlet flow angle near the hub invokesa flow separation on the blade surfaces, thus deteriorating the fan efficiency. The effect of the distance between hub-cap and blade leading edge on the efficiency is also discussed.

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