• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 제13회 정기총회 및 2002년도 동계학술발표회
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• pp.223-233
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• 2002

• 전자공학회논문지A
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• 제28A권10호
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• pp.806-813
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• 1991

In this paper, we suggested the diagnosis of the optical FSK transmitter output characteristics using the Micheloson interferometer. The transmitter is designed by the direct frequency modulation effect of a semoconductor laser diode. The optical FSK transmitter consists of a temperature stabilized semiconductor laser diode and an optimally designed equalizer. It is modulated by 100Mbit/s PRBS Generator to diagonosis of Optical FSK transmitter output characteristics. The Michelson Interferometer is used for the optical frequency discriminator which transforms the output frequency of the transmitter to the amplitude of light. The measurement of the performance of the transmitter to the amplitude of light. The measurement of the performance of the transmitter computer the transmitted data and their eye pattern with the simulation results, the received data and their eye pattern. As the result of experiment, the data transfer rate of the transmitters is 100Mbit/s.

• 한국표면공학회지
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• 제54권6호
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• pp.348-356
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• 2021

In this study, optical diagnosis of plasma was performed for nitrogen doping in graphene using a horizontal inductively coupled plasma (ICP) system. Graphene was prepared by mechanical exfoliation and the ICP system using nitrogen gas was ignited for plasma-induced and defect-suppressed nitrogen doping. In order to derive the optimum condition for the doping, plasma power, working pressure, and treatment time were changed. Optical emission spectroscopy (OES) was used as plasma diagnosis method. The Boltzmann plot method was adopted to estimate the electron excitation temperature using obtained OES spectra. Ar ion peaks were interpreted as a reference peak. As a result, the change in the concentration of nitrogen active species and electron excitation temperature depending on process parameters were confirmed. Doping characteristics of graphene were quantitatively evaluated by comparison of intensity ratio of graphite (G)-band to 2-D band, peak position, and shape of G-band in Raman profiles. X-ray photoelectron spectroscopy also revealed the nitrogen doping in graphene.

• 센서학회지
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• 제23권1호
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• pp.1-6
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• 2014

In many medical image devices, dc noise often prevents normal diagnosis. In wireless capsule endoscopy systems, multipath fading through indoor wireless links induces inter-symbol interference (ISI) and indoor electric devices generate impulsive noise in the received signal. Moreover, dc noise, ISI, and impulsive noise are also found in optical fiber communication that can be used in remote medical diagnosis. In this paper, a blind signal processing method based on the biased probability density functions of constant modulus error that is robust to those problems that can cause error propagation in decision feedback (DF) methods is presented. Based on this property of robustness to error propagation, a DF version of the method is proposed. In the simulation for the impulse response of optical fiber channels having slowly varying dc noise and impulsive noise, the proposed DF method yields a performance enhancement of approximately 10 dB in mean squared error over its linear counterpart.

• 한국분무공학회지
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• 제7권3호
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• pp.31-37
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• 2002

In previous study, diesel-methanol stratified injection system is manufactured and applied to a D.I. diesel engine in order to realize combustion improvement using methanol, which is oxygenated fuel with large latent heat. We know that NOx and soot is reduced by stratified injection of diesel fuel-methanol. Therefore, in the present study, combustion diagnosis using optical measurement is tried to make clear effect of methanol on simultaneous reduction of NOx and soot. Two-color method is used to measure flame temperature and KL value, which is approximately proportional to the soot consentration along the optical path. Laser induced scattering method was used to measure distribution of soot at two dimensional area. Also, it is compared exhaust characteristics of NOx and soot with results of optical measurement.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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• pp.2-3
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• 2003

빛이 생체조직에 조사되면 흡수, 산란과 같은 물리적 반응과 형광, 라만 등과 같은 화학적 반응을 일으키게 된다. 이러한 현상들은 생체조직내의 구성방식에 따라 또는 정상적, 병적 변화에 따라 각기 다르게 나타나며 이들을 이용하여 암 등 병적인 조직변화에 대한 진단이나 조직 내부의 이미징을 수행할 수 있다. (중략)

• 한국한의학연구원논문집
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• 제13권3호
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• pp.105-110
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• 2007

This work reports the pulse diagnosis system using FBG sensors which can display pulse signals detected while oriental medical doctors are conducting pulse diagnoses and simultaneously pressing the sensors by three fingers. Each optical fiber has five FBG sensing units fabricated in 2 mm width and 2 mm inter-sensor spacing. Three optical fibers with the FBG units in the parallel line configuration are then placed on each finger-pressing region and thus overall 9 fibers are used for the pulse measurements on the so-called "chon", "gwan", and "ch대k". A fixture holding the optical fiber arrays is able to adjust the height of the FBG sensing units while placing the fibers on the wrist. The pulse signals detected by the FBG sensors from chon, kwan, and chuk have been analyzed using 4 channel spectrum analyzer connected to the optical fibers. The measured pulse signals exhibit variations due to the nonuniform pressure distributions applied. resulting in the differences in the detected pulse signals between fiber lines. However. this work is the first step towards objective and quantitative analyses of the pulse diagnosis in oriental medicine which has traditionally been performed on subjective basis. Future works will be devoted to improving sensor stability, developing the way applying pressure and algorithms reporting the objective classification of the pulse status from systemic measurements using the sensors instead of relying on the clinicians' diagnoses subjectively performed. A successful pulse diagnosis system emerging in the future is expected to contribute to education as well as promoting pulse diagnosis in oriental medicine to the scientific research area.

• 대한치과보철학회지
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• 제55권1호
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• pp.100-110
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• 2017

목적: 본 논문은 다양한 의료분야 진단에 사용되고 있는 비침습적 영상진단장치 중 낮은 투과 깊이를 가지지만 우수한 분해능과 실시간 영상획득이 가능한 광간섭 단층영상기기(OCT)의 기본 작동 원리, 종류, 장단점 및 응용분야 등을 소개한다. 재료 및 방법: 본 논문에 사용된 연구 데이터는 PubMed, 의료저널 및 관련논문을 검색하여 작성하였다. 결과: OCT를 이용하여 비치습적인 방법으로 실시간 영상 획득 및 고해상도의 생물학적 미세구조 관찰이 가능하며 이는 치아균열, 치아우식, 치아의 마모, 치주질환, 구강암, 그리고 수복물의 미세누출 평가 등에 유용하다. 결론: 현재 다양한 치의학적 진단에 OCT가 사용되고 있으며, 특히 치과보철학 분야에 있어서 지르코니아와 같은 재료의 발전과 함께 더욱 활용범위가 넓어질 것으로 판단된다.

• Korean Journal of Acupuncture
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• 제26권2호
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• pp.1-13
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• 2009

Objective: Optical Coherence Tomography (OCT) has emerged as an important optical imaging modality in non-invasive medical diagnostics. Hence, the aim of this study is to measure the similarity of the diagnosis by a traditional method using doctor's hand for feeling of pulse and by the non-contact/non-invasive pulse analyzing system using OCT on Chon(寸), Kwan(關), Chuk(尺). Method: Four korean medical doctors and the non-contact/non-invasive pulse analyzing system using OCT have measured the rapidity, the dimension, and the power of pulse waves of 25 volunteers. First, four korean medical doctors measured pulse waves of volunteers. During measuring, four doctors were separated from each other and so were volunteers. And then, the pulse waves of volunteers were measured by OCT. This was performed on the right Chon(寸), Kwan(關), Chuk(尺). Results: The study showed that the traditional method and the OCT based method had the 88% matches on the values of the slow and rapid pulse condition (遲數), 64% matches on the values of the small and big pulse condition(微細弱緩大[洪]), and 72% matches on the values of the weak and strong pulse condition(虛實). Conclusions: Based on the high similarities of the measurements of two approaches, we suggest that the OCT based pulse diagnosis method is useful for compensating the traditional method for the pulse diagnosis.

• The Journal of Korean Physical Therapy
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• 제22권4호
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• pp.83-89
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• 2010

Purpose: The goal of this study was to investigate the feasibility for the early diagnosis of inflammatory arthritis by the reconstruction of three-dimensional photoacoustic imaging with a tissue phantom. Methods: Q-switched Nd:YAG laser (l = 532 nm) was applied to a tissue phantom to generate photoacoustic waves, and the acquired photoacoustic signals at different positions around the sample were used to recombine the distribution of the optical absorption and the images were subsequently generated through a reconstruction algorithm. Results: From the acquired photoacoustic signals, the surface andinner core of the phantom was clearly distinguished. Furthermore, the back-projection algorithm was able to reconstruct two-dimensional and three-dimensional photoacoustic images that contained the optical absorption property information of the tissue phantom. Conclusion: The results indicate that the photoacoustic imaging technique has many advantages such as high optical contrast and high acoustic resolution. The acquired images can be used for the early diagnosis of inflammatory arthritis by the structural information obtained from the region of interest.