• Korean Journal of Optics and Photonics
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• v.11 no.6
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• pp.395-399
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• 2000

In white light interferometry, fast and accurate localization of the fringe visibility is the most essential part in application of the principle. So much attention has been concentrated on speeding up the process, we in this study decided to investigate the results of the various peak-finding algorithms. Of the many approaches, two most simplistic algorithms were selected for their straightforwardness and robustness. Both were equally accurate in measuring the step height of a sample, but the method based on the weighted average technique proved to be truer to the surface topography. A model explaining the shortcomings of the correlation technique is presented. ented.

• Journal of Korean Society of Forest Science
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• v.78 no.1
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• pp.35-41
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• 1989

The pollen morphology of nine species and one variety of Korean Salix was investigated by means of light and scanning electron microscopy. Pollen grains are tricolpate or tricolporate varying from subprolate or prolate. Based on aperture and sculpture patterns, the pollen morphology of the investigated Korean Salix appeared to exhibit three different types.

• The Korean Journal of Mycology
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• v.27 no.5 s.92
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• pp.341-344
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• 1999

The genus Hypocrea, a member of the Hypocreales, has yellow to pale yellow-ochre, perithecial stromata and angular to cuboid ascospores. The isolate of Hypocrea microrufa collected on decayed tropical wood at Malaysia is compared with H. rufa and H. microsplendens. This isolation of H. microrufa will be the first record from tropical region and the first description with scanning electron microscopy. The ornamentation of ascospores used one of main taxonomic keys for identification.

• Proceedings of the KAIS Fall Conference
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• 2002.11a
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• pp.260-262
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• 2002

제품의 소재를 미리 테입 형태로 만들어 단면의 경계면을 따라 레이저로 절단하여 적층하는 방식은 제품의 표면에 계단 모양의 무늬가 생기므로 정밀한 제품을 제작하는데 어려움이 있었다. 이를 극복하기 위하여 단면의 경계선을 절단할 때 수직으로 절단하는 것이 아니라 경사면을 따라 절단하여 전체적인 제품의 옆면이 부드럽게 연결되는 경사절단형 임의형상가공시스템을 개발하였다. 이를 위하여 레이저 5축 경사절단기를 개발하였는데, x축과 y축은 상용화되어 있는 x-y table을 이용하였고 z축은 한 개의 z축 이송대를 이용하였다. 롤과 피치를 위하여는 서보모터 두 개를 이용하여 작업대가 회전할 수 있도록 하였다. 이와 같은 레이저 5축 경사절단기를 개발함으로써 시편의 어느 위치에서든 어느 각도로도 절단이 가능하게 할 수 있었다.

• Korean Journal of Optics and Photonics
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• v.10 no.5
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• pp.369-372
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• 1999

We have constructed an interferometric microscopy using a Michelson interferometer and a He-Ne laser. The three dimensional image was obtained by the interference from the reflected signal by a sample surface and from the reflected signal by a mirror. The axial resolution obtained by Michelson interferometric microscopy is as good as that of the white-light interferometer, but the same fringe is obtained when optical path difference is half-wavelength. The image from Michelson interferometric microscopy was compared with the images from the various types of confocal microscopy.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1927-1928
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• 2002

기존의 3차원 형상 측정법은 대부분 접촉식이기때문에 피측정물이 손상이 입거나 Probe의 보정이 필요하거나 Probe가 측정면에 직접 닿지 않는 경우는 측정이 불가능하였다. 또한 많은 점을 측정할 경우측정시간이 많이 걸린다. 물체의 크기가 크거나 측정하고자하는 물체가 무를 경우에는 적합하지 못하다. 이러한 단점은 보완하기 위하여 비접촉식인 측정법 이용한 관측이 대두되게 되었다. 비접촉식에 의한 관측은 물체의 표면을 손상시키지 않으면서 정밀하고 고품질이 요구되는 제품 검사 및 자동화 기술의 발달로 인하여 생산 산업 분야에 이용되고 있다 이에 비접촉식 방식에서도 광학간섭의 하나인 마이켈슨 간섭계를 이용하여 간섭무늬 패턴으로 물체 이미지를 분석하고 CCD카메라에서 영상을 얻어 3차원 물체를 해석하였다.

• Tribology and Lubricants
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• v.24 no.6
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• pp.368-373
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• 2008

This paper will investigate the friction characteristics of a 100m Hexagonal Array, Micro-scale Dimple Pattern, on bearing steel. These characteristics are researched by utilizing a pin-on-disk wear test machine, under various test conditions. The reduction of friction is a necessary requirement for the improved efficiency of this machine. As the speed increases, there is a decrease in the effect of the dimple of friction characteristic, with substantially little change to density. Conversely, as the load increases, the dimple pattern grows larger, resulting in a difference in the texture of these two components. At a dimple density of 10% the friction characteristic is easily demonstrated, with a consistent change in both speed and load.

• The Journal of the Acoustical Society of Korea
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• v.17 no.8
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• pp.41-47
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• 1998

이중 통신(Duplexer) 필터를 설계 및 개발하기 위한 최적조건을 구하기 위해 36° LiTaO3 기판 표면에 빗살무늬 변환기를 사용한 모의 실험을 수행하였으며, 전극 재료로는 Cu-Al(W3%)합금을 이용하였다. 제작한 듀플렉스 필터의 사다리(Lader)형 구조로서 직렬 공진기와 병렬 공진기의 결합으로 필터를 구성하였다. 적절한 통과대역과 저지대역을 형성 하기 위하여 직렬 공진기와 병렬 공지기의 주파수 차이를 30MHz로 했으며, 낮은 저지대역 을 형성하기 위하여 두 공진기의 전기용량의 비는 1로 하였고, 전극의 두께는 2,500Å으로 하였을 때 설계 조건과 일치하는 주파수 응답을 얻었다. 제작한 듀플렉서 필터의 주파수 특 성은 중심 주파수는 836.5MHz와 881.5MHz, 통과대역 폭은 25MHz, 삽입손실은 2.5dB 이하 및 저지대역은 -35dB이하로 나타났다.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.3
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• pp.122-129
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• 2006

We propose the Fizeau-type phase shifting interferometer(FPSI) system for the performance test of high-order aspheric lenses. The proposed system is divided into two parts : optical part and signal processing part. Those two parts are operated by a program for hardware control. We also developed an analysis program adopting the phase shifting algorithm to analyze the obtained interferograms. We can confirm that the proposed system is efficient and adequate by direct comparison with the standard criterion in Mark IV interferometric system of Zygo. The peak-to-valley and RMS values of surface errors which are used to characterize high-order aspheric lenses are 0.845 wave and 0.1871 wave, respectively. The measurement errors between the proposed system and Mark IV are less than ${\lambda}/100$ and the repeatability is also calculated at less than ${\lambda}/100$.

• Research in Plant Disease
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• v.9 no.3
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• pp.162-165
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• 2003

High sporulation method and cultural characteristics of Cercospora capsici causing Cercospora leaf spot of pepper were examined. Optimum temperature for mycelial growth of Cercospora capsici was $25^{\circ}C$. The fungus did not grow below $5^{\circ}C$ and over $35^{\circ}C$. Optimum pH for mycelial growth was pH 4.0~pH 8.0. Mycelial growth was not influenced by light. C. capsici sporulated well on pepper leaf agar (5g/l). A standard method of sporulation established was as follows. The mycelial plugs were ground with some water in motar with pestle. The mycelial suspension was smeared on the surface of medium and incubated for 2~3 days at $20^{\circ}C$. The culture surface was lightly scraped with a brush after adding 1 ml of sterile water to stimulate sporulation and further incubated for 2~3 days.