• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.35-35
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• 2002

나노미터 표준을 확립하기 위하여 일체식 엑스선 간섭계에 광간섭계를 결합시킨 복합간섭계를 구성하였다. 복합간섭계는 광간섭계의 Zero crossing 지점부터 표준시편이 올려진 미소이동대의 이동거리를 변화된 위상값으로 읽고 그 변화량을 고분해능 변위 측정기인 엑스선 간섭계로 읽어들이는 구조로 구성된다. 본 연구에서는 미소이동대의 위치 변화와 관련된 광간섭계의 위상 안정도, 엑스선 간섭계 및 미소이동대의 위치 안정도 등이 나노미터 영역의 길이 측정에 매우 중요한 요인이 되므로, 미소이동대의 위치 변화시 정지상태에서의 위상 잠김 (phase locking) 안정도를 측정하였다. 마이켈슨 레이저간섭계의 한쪽 팔을 고정시키고 다른 한 팔은 미소이동대 위에 반사거울을 설치하여 미소이동대의 움직임을 측정하였다. 보다 안정된 위상잠김 상태를 확보하기 위하여 PID feedback loop controller를 사용하였다. 측정 결과 위상 변동폭이 0.022 degree 이하의 높은 위상잠김 안정도를 확보하였으며, 이를 길이단위로 환산하면 정지상태에서 약 0.02 nm 이하의 위치 안정도를 나타낸다.

• Journal of the Korean Ceramic Society
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• v.13 no.3
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• pp.55-62
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• 1976

순수한 닉켈과 금 박막을 (III)규소 단 결정위에 진공 증착시켰다. Ni/Au/Si나 Au/Ni/Si시료를 진공중에서 약 55$0^{\circ}C$로 가열하였을 때 육방정 혹은 변형된 육방정의 미소 결정들이 규소 기질위에 형성되었다. 이들 미소 결정들의 형성과정 및 조성은 X-선 회절법, scanning electron microscopy 및 scanning Auger microprobe 법을 사용하여 결정하였다. 이들 미소 결정은 NiSi2임이 확인되었다. Ni/Au/Si 시료에서는 Au-Si 공융점(37$0^{\circ}C$) 이상으로 온도가 증가됨에 따라 닉켈과 규소가 Au-Si 공융체 속으로 이동한 후 반응하여 NiSi2를 형성하였다. Au/Ni/Si 시료에 있어서의 Au-Si 공융체 형성은 닉켈 박막에 있는 바늘구멍형의 표면 결함과 관련 지을 수 있겠다. 금이 닉켈 박막의 grain boundary를 통하여 Ni/Si 계면으로 확산되어 그 계면을 습윤시킨 다음 Au-Si 공융체를 형성하였다. 이런 Au-Si 공용체는 닉켈과 규소 원자에 대한 높은 확산 매질로서 작용하여 NiSi2 형성을 촉진시켰다. 표면에 평행한 (III)규소면 위의 NiSi2 미소 결정은 유사한 육방정으로 나타났으며, 경사진 미소결정은 부등변 사변형과 유사하였다. Auger 스펙트럼 및 Ni, Au 및 Si에 대한 내층조성(indepth Composition Profiles)은 NiSi2 미소 결정이 Au-Si 공융체의 matrix에 미소 부분으로 나타났음을 보여주었다.

• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.69-69
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• 2000

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.262-275
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• 2015

The treatment of areas demanding esthetic requirements, such as maxillary anterior teeth, should take into account the achievement of a healthy, harmonious to the surrounding tissue, and an attractive smile line. In this case report, smile line, soft tissue and hard tissue morphology, and the anatomy and proportion of the tooth, must be considered. In patients with unesthetic maxillary anterior ratio due to inadequate gingival contour and diastema caused by peg lateralis, it would be challenging to achieve an esthetic restoration by orthodontic treatment alone. In such case, after orthodontic treatment, dento-gingivo-facial compositional diagnosis and analysis, followed by gingivectomy and prosthodontic restoration is needed to improve the interdental mesial/distal, width/length ratio to achieve a satisfactory esthetic result. In addition, when improving the tooth proportion of peg lateralis by prosthodontic treatment, Porcelain laminate veneer (PLV), which results in less tooth structure loss, reproduction of similar shade to that of the proximal tooth and high transparency, is recommended. This case report demonstrates esthetic improvements by prosthodontic restoration through systematic diagnosis and treatment procedure in patients with unesthetic maxillary anterior proportion after orthodontic treatment due to peg lateralis by means of two female patients aged twenty years old.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.3
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• pp.65-72
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• 2007

Fire is one of important checkpoints in crewed exploration systems, where men inhabit in space. In space, astronaut can't escape from fire out of a spacecraft and not expect any help of fire fighters, either. Accordingly, the best way to stand against fire is to prevent it. But, when fire occurs in space, flame behaviors are quite different from those observed on earth because of micro- or zero-gravity in space. The present paper introduces major research results on flame behaviors under microgravity and fire prevention, detection, and suppression in crewed exploration spacecrafts and international space station based on NASA's FPDS research program.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.15-21
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• 1996

Recently speed control system of the towing carriage have been modified by applying a personal computer in the Ship Model Towing Tank of Seoul National University. With this system the carriage speed could be controled precisely in coincidently with a prescribed speed diagram to evaluate the effect of slight towing speed fluctuation caused by some residual current or standing waves which have believed as trivial phenomena in the towing tank. It is found that the slight speed fluctuation of the carriage could lead to serious error in measurement of resistance test of a ship.

• Korean Journal of Veterinary Research
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• v.41 no.1
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• pp.99-104
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• 2001

To determine if micronucleus (MN) assay could be used to predict the absorbed dose of victims after accidental radiation exposure, we carried out to assess the absorbed dose depending on the numerical changes of MN in human peripheral blood lymphocytes after $^{60}Co\;{\gamma}-rays$ exposure in the range of 0.25 to 1 Gy, respectively. The MNs were observed at very low doses, and the numerical changes according to doses. Satisfactory dose-effect calibration curve is observed after low dose irradiation of human lymphocytes in vitro. When plotting on a linear scale against radiation dose, the line of best fit was $Y=(0.02{\pm}0.0009)+(0.033{\pm}0.010)D+(0.012{\pm}0.012)D^2$. The dose-response curve for MN induction immediately after irradiation was linear-quadratic and has a significant relationship between the frequencies of MN and dose. These data show a trend towards increase of the numbers of MN with increasing dose. The number of MN in lymphocytes that were observed in the control group is $0.1610{\pm}0.0093/cell$. Accordingly, MN assay in human peripheral lymphocytes could be a useful in viva model for studying radio-protective drug sensitivity or screening test, microdosimertic indicator and radiation-induced target organ injury. Since MN assay is simple, rapid and reproducible, it will also be a biodosimetric indicator for individual dose assessment after accidental exposure.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.99-109
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• 2016

This paper presents a method for generating spatiotemporal images to detect the leukocyte motions in a microvessel. By using the constraint that the leukocytes move along the contour line of a blood vessel wall, the method detects leukocyte motions and then generates spatiotemporal images. the translational motion by a movement in vivo is removed first by the template matching method. Next, a blood vessel region is detected by the automatic threshold selection method to binarize the temporal variance image, then a blood vessel wall's contour is expressed by B-spline function. With the detected blood vessel wall's contour as an initial curve, the plasma layer of the best accurate position is determined to be the spatial axis by snake. Finally, the spatiotemporal images are generated. The experimental results show the spatiotemporal images are generated effectively through the comparison of each step of three image sequences.

• Journal of the Institute of Convergence Signal Processing
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• v.15 no.4
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• pp.128-134
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• 2014

In this paper, we propose a detection method of the leukocyte motions in a microvessel by using spatiotemporal image analysis. The leukocyte motions that adhere to blood vessel walls can be visualized to move along the blood vessel wall's contours in a sequence of images. In this proposal method, we use the constraint that the leukocytes move along the blood vessel wall's contours and detect the leukocyte motions by using the spatiotemporal image analysis method. The generated spatiotemporal image is processed by a special-purpose orientation-selective filter and then subsequent grouping processes are done. The subsequent grouping processes select and group the leukocyte trace segments among all the segments obtained by simple thresholding and skeletonizing operations. Experimental results show that the proposed method can stably detect the leukocyte motions even when multiple leukocyte traces intersect each other.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.65-73
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• 2000

An elasto-plastic constitutive model was proposed, in which the behavior at small-to-large strain level can be modeled. The proposed model is based on the anisotropic hardening description with the generalization of isotropic hardening rule and the total stress concept. From a mathematical approach it was proved that the model includes the previous successful models. The model was verified by a series of resonant column tests, torsional shear tests and triaxial tests, and the proposed model predicted small-to-large strain behavior more consistently and accurately than the hyperbolic model and the Ramberg-Osgood model for a weathered granitic soil. In addition, the nonlinearity under small strain condition was predicted appropriately for the torsional shear test results.