• The Journal of the Acoustical Society of Korea
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• v.18 no.3
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• pp.55-61
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• 1999

In this study, we have constructed the acoustic microscope using quadrature technique and analyzed the relative variation of image intensity and the quality of image by reconstructing the amplitude and phase image for surface defects with tiny hight variation. In this experiment, we have constructed the scanning acoustic microscope using the focused transducer with 3㎒ center frequency and the quadrature detector. And we have fabricated aluminum samples with round defects whose depth is different and reconstructed the amplitude and phase images for the samples. One sample has round defects with 2㎜ diameter and 100㎛ depth and the other has round defects with 4㎜ diameter and 5㎜ depth. In the result of line scanning for the sample with 100㎛ round defects, it has been shown that the variation rate of amplitude image intensity is 7% and the variation rate of phase image intensity is 89%. The phase image has better contrast than amplitude image for the sample. In contrast to this, the amplitude image has better contrast than phase image for the sample with 5㎜ depth's defects. Accordingly there is big difference between amplitude image and phase image for depth variation of defects whose boundary is 1 wavelength. Consequently the acoustic microscope using quadrature detector can be evaluated efficiently more than using envelope detector, for detecting defects which have height variation less than 1 wavelength. And also the phase image and the amplitude image can be used for detecting defects of tiny height variation with complimentary relation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.335-338
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• 2004

In this study has developed analysis system for automatic inspection of FPD(Flat Panel Display) characteristic, such as brightness, view angle, color ratio in the manufacturing process. Developed system consists of inspection-sensor part, acquiring a data by 3-CCD Color CCD camera and Inspection-stage part, driving a FPD holder to rotation and tilt direction. In experiment results, we could have ensured easily brightness distribution, available view angle, color reproduce and could expect to improve the quality, productivity, and yield.

• The Journal of Information Technology
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• v.4 no.2
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• pp.129-136
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• 2001

Most of the acoustic microscopes have been constructed acoustic image by simply measuring the amplitude of the reflected signal from the specimen. This method fails to produce images of good quality because the change in amplitude is not sensitive enough to specimen with fine variation. In this paper, we have been constructed the acoustic microscope system which has been able to measure simultaneously the amplitude and phase of the reflected ultrasonic signal. And also we have been constructed the amplitude and phase images for the 500 won coin as a sample and the alumium spacimen with internal round defect, and compared and analyzed these images. In expermental result, the phase image have shown better sensitive than the amplitude image and given better contrast for the micro height variation of specimen. It will be expected that the phase image can be used as an additional bit of information to improve ambiguituities in amplitude image on nondestructive testing for specimen with fine variation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1529-1534
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• 2012

In this study, tensile tests for 12-${\mu}m$-thick copper thin foils were performed by using the DIC method. The DIC method provided precise stress-strain curves for thin film materials, and a commercial inkjet printer can be simply and effectively used for printing speckle patterns on the specimen of Cu thin films whose surface contrast is too low to apply the DIC method. The mechanical properties of Cu thin foils obtained in this study are as follows: elastic modulus E = 89.2 GPa, 0.2% offset yield stress $S_{0.2%}$= 232.8 MPa, tensile strength $S_u$= 319.2 MPa, elongation at fracture ${\varepsilon}_f$=16.8 %, and Poisson's ratio ${\nu}$= 0.34.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.126-136
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• 2019

The film born by Lumiere brothers in 1895 was not the first. Edison, who invented the Kinetograph four years ago, has already made dozens of films. But it has been relatively undervalued. That's because the platform for projecting a movie was through a single person viewer called Kinetoscope. However, the physical characteristics of the film itself are the same as those of modern films, and have a unique aesthetic distinction compared to other early films. The subject is entertainment-oriented, and the image is characterized by contrast effect. In addition, even before the birth of the film, it shows the important creative elements and genres pursued by fictional films, and has industrial production systems and experts. If Lumiere's film is the beginning of a documentary film that portrays the fact, Edison's film deserves historical value as the beginning of popular film, which is the hallmark of modern cinema.