• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.157-161
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• 2007

There are technological changes to reduce the size and weight of electronic components and to accommodate multi-functions in them. To meet this trend, more complicated technological processes are required. To maintain the processes, more accurate inspection systems are also necessary. Therefore, new inspection methods are needed, which is differ from conventional inspection methods such as electrical test methods ICT(In-Circuit Test), FCT(Function Test) and visual test using optical equipments. One of the possible approaches is non-destructive test using X-ray. In this paper, an inspection method using X-ray is developed and applied to inspection of soldering state and internal defects of electronic components.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.9
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• pp.1796-1804
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• 1992

Profiles of soot volume fraction, average diameter and particle number density have been measured using a light scattering and extinction technique in a coannular propane diffusion flame at atmosperic pressure. Temperature profiles were also obtained using a thermocouple technique. Measurements show that soot is first observed to form low in the flame in an annular region inside the main reaction zone. At higher locations this annular region widen until entire flame is observed to contain particles. Soot volume fraction and particle diameter profiles peak some 1mm on the fuel side of peak temperature and increase with height to oxidation region. Number density of the flame core drop steeply from formation region to growth region and relatively invariant to some height and decay out at flame tip.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.628-630
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• 2017

관상동맥의 협착 병변의 위험성을 치료 및 예방하기 위하여 FFR(Fractional flow reserve)이라는 지표를 사용한다. 기존의 임상에서 FFR을 측정하기 위하여 침습적인 방법을 이용하여 진행하였다. 이러한 침습적 방법은 부작용의 위험성을 가지고 있기 때문에 컴퓨터 시뮬레이션을 통해 계산하면 위험성을 해소할 수 있다. 하지만 현재 컴퓨터 시뮬레이션은 CT image를 이용하기 때문에 칼슘을 정확히 구별하거나 지질의 위치 등을 확인하는 것이 어렵기 때문에 FFR 결과에 오류를 발생시킬 수도 있고, 또한 전체 관상동맥을 해석하기 때문에 많은 계산량이 필요하다. 본 연구에서는 최근 높은 해상도를 가진 OCT(Optical Coherence Tomography)를 이용하여 이러한 한계점을 극복하고자 하고, 임상에서 측정한 FFR과 OCT에서 측정된 FFR은 비교하는 것이 목적이다.

• Broadcasting and Media Magazine
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• v.18 no.3
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• pp.95-108
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• 2013

디지털 홀로그래픽 현미경이나 정량적 위상 현미경(quantitative phase microscopy)과 같은 기존의 간섭현미경은 3차원 이미징 기술로 분류되는데, 이는 획득한 이미지의 복소장(complex field)을 계산을 통해 다른 깊이로 전파시킬 수 있기 때문이다. 그러나 엄밀한 의미에서는 하나의 복소장 이미지는 단지 2차원 맵이기 때문에 근본적으로는 샘플의 2차원 정보만을 가지고, 물체의 3차원 구조의 일부분을 측정하는 것에 지나지 않는다. 본 논문에서는 1969년에 Wolf가 제안한[1,2] 홀로그래픽 회절 토모그래피(Optical Diffraction Tomography: ODT)를 실험적으로 구현한 3차원 위상 현미경(Tomographic Phase Microscopy: TPM)을 소개하고자 한다. TPM은 샘플을 다양한 각도로 조명하여 서로 다른 입사각에 대해 복소장 이미지를 얻고, ODT를 통해서 샘플의 3차원 구조를 복원해내는 기술이다. 보다 구체적으로는 다양하고 독립적인 2차원 이미지들을 샘플의 3차원 푸리에 공간에 맵핑함으로써 샘플 단면의 흡수율과 굴절률을 복원할 수 있다. 굴절률은 분자 농도와 비례하기 때문에, 살아있는 세포에 대한 굴절률의 3차원 맵을 얻을 수 있으면 세포 내부의 분자 구성을 연구할 수 있고, 이를 통해 다양한 생의학적 응용을 연구할 수 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.321-323
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• 2004

We developed the monte-carlo simulation code for analysis of the On signal in dental medium. In calculation, we obtain the two different propagation signals as a function of the probing depth. Signal 2 begins to exceed the signal 1 at a very small probing depth(=60${\mu}{\textrm}{m}$). For reduce the signal, detection area is limited to radius and detection angle. As numerical result, probing depth becomes appoximately 500${\mu}{\textrm}{m}$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.140-143
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• 2004

The mage enhancement of dental On image using wavelet coefficients is presented. The processing is that make gray image from On image by preprocessing, extract high frequency from detail coefficient after acquisition detail coefficient by wavelet transform and emphasize edge appling input image. Experimental results show that enhanced contrast of dental On image, improved mage quality.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.212-214
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• 2002

Basically, OCT use the interference effect of Michelson interferometer. The receiver noise of interferometer is a important fact to improve the system performance. To improve the system performance for high resolution image processing, we design a interferometer topology adding the attenuator to the reference arm. In this paper, we design the receiver noise parameter and computer simulation. In this results, SNR of the new topology system is improved 5dB compare to standard interferometer.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.27 no.2
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• pp.89-100
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• 2014

Vogt-Koyanagi-Harada(VKH) Disease is a bilateral granulomatous uveitis often associated with exudative retinal detachment and extraocular manifestations, such as pleocytosis in the cerebrospinal fluid and, in some case, vitiligo, poliosis, alopecia, and dysacusis. There has been no previous report for the disease in the field of Korean traditional medicine. The case was treated with conventional medical intervention and Korean traditional treatment including acupuncture and herbal medicine. The case was discharged with improvement in fundus photography and optical coherence tomography. The authors report the case to suggest that Korean medical approach combined with conventional treatment can be helpful for the disease.

• Journal of Yeungnam Medical Science
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• v.35 no.2
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• pp.232-235
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• 2018

Fabry disease (FD) is an X-linked, recessively inherited, rare, progressive, disorder of glycosphingolipid metabolism affecting multiple organs resulting in organ dysfunction. It is rare to find only one FD affected subject with a de novo mutation. Here we report a case of a 41-year-old Asian male diagnosed with de novo FD. Comprehensive ophthalmological evaluation was performed using slit lamp, color fundus photography, optical coherence tomography, fluorescein angiography, and indocyanine green angiography. On slit lamp examination, cornea verticillata and slightly tortuous, and aneurysmal dilatation of inferior bulbar conjunctival vessels were observed. Other imaging modalities showed unremarkable findings. Cornea verticillata and inferior bulbar conjunctival vascular abnormalities may be detected earlier than other ocular abnormalities in de novo FDs like hereditary FDs.

• Electronics and Telecommunications Trends
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• v.36 no.5
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• pp.1-8
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• 2021

Over the last three decades, the development of Ti:sapphire femtosecond lasers has led to advancements in scientific and industrial fields. In particular, these advanced lasers show great potential for applications with bio-imaging and medical surgery, such as two-photon microscopy, nonlinear Raman microscopy, optical coherence tomography, and ophthalmic surgery. Herein, we present a detailed description of the theoretical and experimental physics of Kerr-lens mode-locked femtosecond Ti:sapphire lasers and its two-photon microscopy.