• Journal of Biomedical Engineering Research
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• v.30 no.6
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• pp.476-481
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• 2009

The most troublesome artifacts in micro computed tomography (micro-CT) are ring artifacts. The ring artifacts are caused by non-uniform sensitivity and defective pixels of the x-ray detector. These ring artifacts seriously degrade the quality of CT images. In flat-panel detector based micro-CT systems, the ring artifacts are hardly removed by conventional correction methods of digital radiography, because very small difference of detector pixel signals may make severe ring artifacts. This paper presents a novel method to remove ring artifacts in flat-panel detector based micro-CT systems. First, the bad lines of a sinogram which are caused by defective pixels of the detector are identified, and then, they are corrected using a cubic spline interpolation technique. Finally, a ring artifacts free image is reconstructed from the corrected projections. We applied the method to various kinds of objects and found that the image qualities were much improved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.388-391
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• 2003

The properties of these detectors can be controlled by electronics and exposure conditions. Flat-panel detectors for digital diagnostic imaging convert incident x-ray images to charge images. Flat panel detectors gain more interest real time medical x-ray imaging. Active area of flat panel detector is $14{\times}17$ inch. Detector is based on a $2560{\times}3072$ away of photoconductor and TFT pixels. X-ray conversion layer is deposited upper TFT array flat panel with a 500m by thermal deposition technology. Thickness uniformity of this layer is made of thickness control technology(5%) of thermal deposition system. Each $139m{\times}139m$ pixel is made of thin film transistor technology, a storage capacitor and charge collection electrode having geometrical fill factor of 86%. Using the separate driving system of two dimensional mosaic modules for large area, that is able to 4.2 second per frame. Imaging performance is suited for digital radiography imaging substitute by conventional radiography film system..

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.220-224
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• 2005

The technology trend of Flat Panel Display (FPD) equipments have been demanded that there are compact and multi-function. Therefore, nano/micro scale patterned on polymeric materials of Back Light Unit (BLU) in Liquid Crystal Display (LCD) that has been investigated. This paper describes a series of Horizontal Type Micro Tensile Tester that were carried out to investigate the load strain distance performance of typical polymeric material sheets. The polymeric materials film that micro size shaped specimens for tensile test are used by Cold-Isostatic-Press (CIP). Test equipment is Horizontal type Micro Tensile Tester that is presented to measure the micro scale mechanical property of thin film for FPD. This paper presents which easy testing tools measure for micro patterned on polyethylene (PET) specimens.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.678-682
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• 2007

It is conducted that study on corner crack protection for various thermal environment in a flat panel display. Most of the consumer electronics consist of a plastic and a metal structure. And different properties of materials could cause failure of structural reliability due to the various operating temperatures. Especially for front bezel with thin and slender structure, the effect of temperature is significant, and the design for crack protection is crucial for thermal reliability of displays. In this study, it is prescribed the behavior of the front bezel in flat panel display for various operation temperatures and proposed design parameters to ensure the structural reliability of displays.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.231-234
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• 2006

과거 디스플레이 장치로서 사용되던 CRT를 대신하여, 상대적으로 두께가 않고 가벼운 영상장치인 평판 디스플레이(Flat Panel Display, FPD)의 사용이 급증하고 있다. 이렇게 평판표시장치(Flat Panel Display) 산업의 폭발적인 성장과 함께 새로운 공정개발을 통해 짧은 시간에 더 많은 양을 생산하고, 불량률을 낮추는가에 생산업체의 사활이 달려있다. 본 논문은 FPD 공정에서 품질을 결정하는 여러 요인 가운데 비중이 큰 박막 두께의 제어를 지능화 알고리즘을 통해 해결하고자 한다. 이는 불필요한 과정을 줄여 공정경비를 절감 및 소요시간을 단축하고, 정밀하게 두께를 측정하는 것을 가능하게 한다. 마지막으로, 제안한 알고리즘을 광 간섭 두께 측정기를 통해 얻은 실제 값을 가지고 시료의 두께를 측정한다.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.122-124
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• 2005

The flat panel lamp is used as back light. It is perceived the best type for the wide size LCD of back light system. However, the flat panel lamp has high value of heat. So it need to improve efficiency. Therefore, more researches are requested for the back light of the flat panel lamp. In this paper, the properties of spectrum is investigated according to change in frequency from 30kHz to 60kHz using power supplies voltage with changing from 500V to 700V. As a result, main spectrum peak of plasma showed in 450[nm], 630[nm], 750[nm] and spectrum peak of 750nm is the highest.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.249-250
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• 2006

Recently FPD(Flat Panel Display) is used in various field to display enormous information. So cutting technique of flat panel display is needed for producing variety display merchandises. In present, cutting methods of flat panel glass includes breaking process. But this process occurs many glass particles. This glass particles are directly related badness of merchandise and falling productivity. In this paper, to cut front substrate glass of LCD and to get optimized cutting condition are tried fur eliminating breaking process with developed glass cutting machine using a Piezoelectric ceramics actuator. It is known that the vibration of Piezoelectric Ceramic have effect in crack proceeding through the analysis of fracture section.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.4
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• pp.86-100
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• 2008

This article reviews the development of flat-panel detectors for digital radiography based on amorphous materials, Important design parameters and developments are described for the two main components of flat-panel detectors: the X-ray converter and the readout pixel array. This article also introduces the advanced development concepts of new detectors. In addition, the cascaded linear systems method is reviewed because it is a very powerful tool for improving the design and assessment of X-ray imaging detector systems.

• Wind and Structures
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• v.16 no.2
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• pp.213-224
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• 2013

One of the key issues affecting the promotion of solar water heaters in Taiwan is the severe impact of typhoon each year. An experimental study was conducted to investigate the wind uplift characteristic of a solar collector model with and without a guide plate. The guide plate with different lengths and orientations with respect to wind direction was adopted. It is found that the wind uplift of a solar collector is associated with the tilt angle of the flat panel as expected. A cavity formed between the guide plate and the flat panel has a significant effect on the distributions of streamwsie and lateral pressure. Reduction in uplift is essentially coupled with the projected area of a guide plate on the lower surface of the tilt flat panel.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.3
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• pp.453-458
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• 1987

Amorphous silicon thin-film transtors (TFT's) have been designed and fabricated on glass substrates. The hydrogenated amorphous silicon (a-Si:H) thin-film has been deposited by decomposing silane(SiH4) in hydorgen ambient by rf glow discharge method. Amorphous silicon nitride(a-Si:H) has been chosen as the gate dielectric material. It has been prepared by decomposing the mixed gas of silane(SiH4) and ammonia(NH3). The electrical properties and performance characteristics of the thin-film transistrs have been measured and compared with the requirements for the switching elements in liquid crystal flat panel display. The results show that liquid crystal flat panel displays can be fabricated using the thin-film transistors described in this paper.