• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1962-1963
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• 2002

The hand-piece fiber optics is applied to medical appliances such as glaucoma theraphy to focus semiconductor laser on the affected parts efficiently. In this paper, we evaluate optical properties such as beam power and radius of a hand-piece probe by experiments and we also simulate the hand-piece optics by ray tracing method in order to study major parameters to optimize focalization ability. As results, we show experimental and simulation results of the hand-piece optics and also summarize several requirements that have to be considered in optimizing the hand-piece optics.

• Current Optics and Photonics
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• v.8 no.4
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• pp.327-344
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• 2024

Optical phantoms are essential in optical imaging and measurement instruments for performance evaluation, calibration, and quality control. They enable precise measurement of image resolution, accuracy, sensitivity, and contrast, which are crucial for both research and clinical diagnostics. This paper reviews the recent advancements and challenges in phantoms for optical coherence tomography, photoacoustic imaging, digital holographic microscopy, optical diffraction tomography, and oximetry tools. We explore the fundamental principles of each technology, the key factors in phantom development, and the evaluation criteria. Additionally, we discuss the application of phantoms used for enhancing optical-image quality. This investigation includes the development of realistic biological and clinical tissue-mimicking phantoms, emphasizing their role in improving the accuracy and reliability of optical imaging and measurement instruments in biomedical and clinical research.

• 순환기질환의공학회:학술대회논문집
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• 2006.10a
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• pp.49-49
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• 2006

• Current Optics and Photonics
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• v.7 no.4
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• pp.457-462
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• 2023

Quantitative measurement of trace ethane is important in environmental science and biomedical applications. For these applications, we typically require a few tens of part-per-trillion level measurement sensitivity. To measure trace-level ethane, we constructed a cavity ring-down spectroscopy setup in the 3.37 ㎛ mid-infrared wavelength range, which is applicable to multi-species chemical analysis. We demonstrated that the detection limit of ethane is approximately 300 parts per trillion, and the measured concentration is in agreement with the amounts of the injected sample. We expect that these results can be applied to the chemical analysis of ethane and applications such as breath test equipment.

• Current Optics and Photonics
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• v.3 no.4
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• pp.351-351
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• 2019

• BMB Reports
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• v.49 no.9
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• pp.497-501
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• 2016

Wide-line ¹H NMR intensity and differential scanning calorimetry measurements were carried out on the intrinsically disordered 73-residue full transactivation domain (TAD) of the p53 tumor suppressor protein and two peptides: one a wild type p53 TAD peptide with a helix pre-structuring property, and a mutant peptide with a disabled helix-forming propensity. Measurements were carried out in order to characterize their water and ion binding characteristics. By quantifying the number of hydrate water molecules, we provide a microscopic description for the interactions of water with a wild-type p53 TAD and two p53 TAD peptides. The results provide direct evidence that intrinsically disordered proteins (IDPs) and a less structured peptide not only have a higher hydration capacity than globular proteins, but are also able to bind a larger amount of charged solute ions.

• Journal of the Korean Society of Visualization
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• v.9 no.3
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• pp.3-9
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• 2011

• Korean Journal of Acupuncture
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• v.28 no.1
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• pp.53-60
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• 2011

Objectives : Cupping therapy has been used as various treatment methods in oriental medicine clinic for a long time. Specially, Cupping stimulation caused skin hyperpigmentation which has been used as diagnosis method for extravasated blood & inner organs functional disease. But it was difficult to quantitatively measure and analyze the interrelation between extravasated blood and skin hyperpigmentation. The aim of this study is to measure the acupoint's RGB and melanin change pattern by stimulating under fixed 80kPa negative pressure and to evaluate the extravasated blood. Methods : To evaluate extravasated blood, 10 acupoints (left/right BL13, BL15, BL18, BL20, BL23) were stimulated by treatment 80kPa negative pressure for 1 minute. And then we measured the acupoints' skin color change patterns using the color meter, followed by RGB analysis and melanin change pattern. Results and Conclusions : We could observe the correlation of the acupoints' skin color condition related with RGB change pattern. All acupoints' color change degree were different. Regardless of acupoints' color degree due to extravasated blood, we observed in common the fact that RGB values decreased after stimulation and steadily increased according to time. We observed that melanin index increased after stimulation and recovered before stimulation-condition after the lapse of time. In other words, we confirmed the correlation between raised color change degree and $L^*a^*$ index change pattern. Therefore we observed the possibility of charting the $L^*a^*$ index following extravasated blood.

• Current Optics and Photonics
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• v.7 no.5
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• pp.569-573
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• 2023

We utilized terahertz time-domain spectroscopy (THz-TDS) to measure the thickness and electrical properties of nickel-chromium (Ni-Cr) films. This technique not only aligns well with traditional methods, such as haze-meter and transmission-densitometer measurements, but it also reveals the electrical properties and thickness of films down to a few tens of nanometers. The complex conductivity of the Ni-Cr thin films was extracted using the Tinkham formula. The experimental values closely aligned with the Drude model, indicating the reliability of our Ni-Cr film's electrical and optical constants. The thickness of Ni-Cr was estimated using the complex conductivity. These findings emphasize the potential of THz-TDS in quality control of metallic nanofilms, pointing toward an efficient and nondestructive test (NDT) for such analyses.

• ETRI Journal
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• v.30 no.4
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• pp.615-617
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• 2008

A novel and compact elliptic-function bandpass filter is proposed in this letter. The techniques of slot etching and the addition of open stubs are applied to enhance the self-inductance and self-capacitance of hexagonal open-loop resonators. Thus, size reduction and improved transmission performance are obtained. Compared to the performance of the conventional design, the central frequency and insertion loss are reduced by 28% and 3.1 dB, respectively. Measurements show that the proposed filter has a fraction bandwidth of 23% at the central frequency of 1.84 GHz, and its insertion loss in the passband is less than -1.5 dB. The bandpass filter occupies only 12 mm${\times}$21.2 mm (approximately $0.24{\lambda}_g{\times}0.14{\lambda}_g$).