• 비파괴검사학회지
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• 제16권4호
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• pp.234-240
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• 1997

기존의 Scanning Laser Acoustic Microscope (SLAM)에 횡파를 사용함으로써 분해능을 개선시키는 방법을 연구하였다. 액체-고체 경계에서는 모드 변환이 발생하여 액체에서 입사되는 종파 에너지의 일부분은 고체 시험편 내에서 횡파 에너지로 변환된다. SLAM의 분해능은 수신측의 레이저 빔 폭과 입사되는 초음파의 파장에 의하여 결정되고, 고체에서 횡파의 파장은 같은 주파수의 종파의 파장보다 짧기 때문에 횡파를 사용한다면 높은 분해능을 얻을 수 있다. 종파와 횡파를 사용하였을 때에 얻어지는 SLAM 영상을 시뮬레이션을 통하여 비교하여 횡파를 이용하면 분해능이 향상됨을 입증하였다. SLAM을 횡파 모드에서 동작시키기 위하여 입사각을 조절할 수 있는 ??지를 제작하였고, 알루미늄 시험편에 대하여 실험한 결과로부터 종파 모드 SLAM에 의한 영상보다는 횡파 모드 SLAM의 영상의 콘트라스트가 양호함을 확인하였다.

• 한국광학회지
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• 제18권5호
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• pp.309-316
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• 2007

주파수영역 광 간섭 단층촬영 시스템을 위한 파장가변 광원과 주파수 보정(calibration)을 위한 신호처리계를 구현하였다. 제작된 레이저의 평균출력을 부스터(booster) 반도체 광 증폭기를 이용하여 14 mW까지 증폭시키고, 레이저 스펙트럼의 편이(shift)를 보상하였다. 패브리-페롯 에탈론(Fabry-Perot etalon)과 디지털 신호처리(digital signal processing)로 신호처리계를 제작함으로서 파장가변광원의 속도가변에 따른 비트주파수(beat frequency)의 넓어짐을 보정하였다. 제작된 광 간섭 단층촬영 시스템은 종방향 주사속도 154.4 kHz, 측정깊이 0.95 mm, 종방향 분해능 $12{\pm}0.37{\mu}m$의 특성을 가진다.

• 조명전기설비학회논문지
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• 제21권7호
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• pp.54-60
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• 2007

15개의 광섬유 격자를 이용하여 전력설비의 온도변화를 상시 감시하는 분배형 광섬유 온도센서 시스템을 제작하였다. MEMS 파장가변 필터를 사용하는 복조시스템의 비선형 동작특성에 의한 측정오차를 보상하기 위하여 Fabry-Perot ITU 필터의 투과파장을 기준으로 하는 다항식 피팅 알고리즘을 사용하였다. 실험을 통하여 보상알고리즘이 구동주파수와 무관하게 센서시스템의 정밀도를 유지하는 것을 확인하였으며 기준 온도계로 사용한 써모커플과의 선형화 오차는 약 0.18[%]로 측정되었다.

• 한국재료학회지
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• 제16권10호
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• pp.624-628
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• 2006

In this study, divalent europium-activated $NaCaPO_4$ green phosphor powders were prepared by the chemical synthetic method followed by heat treatment in reduced atmosphere, and the crystal structures, morphologies and photoluminescent properties of the powders were investigated by x-ray powder diffraction, scanning electron microscope and spectrometer for the first time. The effects of Ca/P and Na/Ca mole ratios on the final products were also investigated. The influences of input amount change of europium as the activator on the light emission intensity were studied, and the resulting concentration quenching phenomenon was observed. The optimized synthesis conditions obtained in this study were Ca/P mole ratio 1.2, Na/Ca mole ratio 3.0 and 4 mole%Eu. The peak wavelength was 505 nm for all the samples. The result of excitation spectrum measurement indicated that the excitation efficiency was high for the long-wavelength UV region. It was thus concluded that the samples prepared in this study can be successfully applied for the light-emitting devices such as LED excited with long-wavelength UV light sources.

• 한국전기전자재료학회논문지
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• 제17권1호
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• pp.70-74
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• 2004

We investigated transmittance, surface characteristics, and resistivity according to bending of ITO(indium tin oxide) film with four other multi -harrier film). Transmission data of ITO film with four ITO films showed there was about large 90％ transmission above 550nm wavelength at three multi-barrier structures. But, both-side hard coated structure showed relatively low 75％ transmission above 550nm wavelength. And, surface images measured from SEM (scanning electron microscope) showed both-side hard coated structure have a tendency of more roughness. Also, resistivity change of four other multi-barrier film showed there was the lowest change at one-side hardcoated structure. Subsequently, with result of resistivity change according to position, we knew the resistivity change of the center increased rapidly than that of the edge.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.264-267
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• 2007

It is important to reduce optical losses from front surface reflection to improve the efficiency of crystalline silicon solar cells. Surface texturing by isotropic etching with acid solution based on HF and $HNO_3$ is one of the promising methods that can reduce surface reflectance. Anisotropic texturing with alkali solution is not suitable for multicrystalline silicon wafers because of its various grain orientations. In this paper, we textured multicrystalline silicon wafers by simple wet chemical etching using acid solution to reduce front surface reflectance. After that, surface morphology of textured wafer was observed by Scanning Electron Microscope(SEM) and Atomic Force Microscope(AFM), surface reflectance was measured in wavelength from 400nm to 1000nm. We obtained 29.29% surface reflectance by isotropic texturing with acid solution in wavelength from 400nm to 1000nm for fabrication of multicrystalline silicon solar cells.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.555-557
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• 1995

In near field optics, optical fiber probe is smaller than the wavelength of light. This small probe makes it possible to overcome the diffraction limit due to wave property of light. In conventional optical systems, the image resolution is governed by wavelength. But in NSOM, it is determined by probe tip size and probe shape. Therefore probe tip size and shape are very important points in near field optics. In this paper, we will suggest the new fabrication methods of optical fiber probe and show that the probe tip size is sub-micrometer using SEM.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2002년도 추계학술대회 발표 논문집
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• pp.130-136
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• 2002

Device makers want to make higher density chips as devices shrink, especially WSix poly stack down is one of the key issues. However, EPD (End Point Detection) time delay was happened in DPS+ poly chamber which is a barrier to achieve device shrink because EPD time delay killed test pattern and next generation device. To investigate the EPD time delay, a test was done with patterned wafers. This experimental was carried out combined with OES(Optical Emission Spectroscopy) and SEM (Scanning Electron Microscopy). OES was used to find corrected wavelength in WSix stack down gate etching. SEM was used to confirm WSix gate profile and gate oxide damage. Through the experiment, a new wavelength (252nm) line of plasma is selected for DPS+ chamber to call correct EPD in WSix stack down gate etching for current device and next generation device.

• 대한화장품학회지
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• 제40권3호
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• pp.259-268
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• 2014

최근 여러 가지 비침습적인 방법으로 피부조직의 생검 또는 조직학적 처리과정 없이 피부의 실시간 이미지를 이용한 연구가 가능해졌다. Confocal scanning laser microscope (CSLM) 이미지는 830 nm의 근적외선 파장을 사용하는 비침습적 방법으로 피부의 내부 구조를 이미지화할 수 있으며, CSLM을 이용한 연구를 통해 비침습적인 피부 측정법으로 색소 침착 부위의 기저층과 진피 유두 사이에서 melanin cap, papillary ring과 같은 지표가 뚜렷하게 관찰된다고 보고되었다. 본 연구에서는 scanning probe image processor (SPIP)소프트웨어를 사용하여 CSLM 디지털 이미지 정량 분석을 처음 시도하였으며 본 연구결과는 정성적 피부조직 이미지 데이터를 정량화함으로써 향후 CSLM 활용범위를 높이게 될 것으로 기대하고 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1271-1276
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• 2007

The most powerful analytical equipment usually comes at the cost of having the highest demand for space. Where electron microscopes has traditionally required a room to themselves, not just for reasons of their size but because of ancillary demands for pipes and service. The simple optical microscopes, of course, can occupy the desk-top, but because their performance is limited by the wavelength of light, their powers of magnification and resolution are inferior to that of the electron microscope. Mini SEM will sit comfortably on a desk-top but offers magnification and resolution performances much closer to that of a standard SEM. This new technique extends the scope of SEM as a high-resolution microscope, relatively cheap and widely available imaging tool, for a wider variety of samples.