• Corrosion Science and Technology
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• 제19권6호
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• pp.310-317
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• 2020

This study investigated the damage to the specimen due to liquid droplet impingement erosion corrosion, which improved the corrosion resistance and durability via hard anodization of 5083-H321 aluminum alloy, which is widely used for small ships and marine structures. The experiment combined liquid droplet impingement erosion and electrochemical equipment with the flow rates in natural seawater solution. Subsequently, Tafel extrapolation of polarization curves was performed to evaluate damage due to the liquid droplet impingement erosion corrosion. The damaged surface was observed using a 3D microscope and a scanning electron microscope. The degree of pitting damage was measured using the Image J program, and the surface hardness was measured using the micro-Vickers hardness tester. The corrosion current density, area, depth, and ratio of the damaged areas increased with the increase in flow rate. The grain size of the damaged area at a flow rate of 20 m s-1 showed fewer and minor differences in height, and a smooth curved shape. The hardness of the damaged surface tended to decrease with increase in flow rate.

• 한국전기전자재료학회논문지
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• 제29권5호
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• pp.317-320
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• 2016

In order to acquire clear images capable of diagnosing cracked tooth by light transmission, the optical properties of LED light source were examined. Based on the results, the prototype which basically consisted of LED light source, bandpass filter and commercial compact camera module was designed and manufactured. The wavelength and optical power of the LED in the prototype were 850 nm and 7 mW/Sr, respectively. In evaluation of the prototype using microscope, the observation of the crack with width of above $17{\mu}m$ was possible. In addition, image analysis to obtain shape information on the observed tooth cracks was carried out.

• 한국광학회지
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• 제9권6호
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• pp.362-367
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• 1998

중심거리측정법은 서로 붙어있는 두 입자 중심점간의 거리를 측정하여 입자의 지름을 구하는 방법이다. 표면장력에 의해 배열이 형성된 시편 입자들의 초점군을 투과식 광학현미경에 평행 레이저광을 입사시켜 얻어내고 CCD 카메라로 영상을 받아 전산 분석하였다. Global lab image라는 영상처리 프로그램으로 초점들의 중심점을 찾고 붙어있는 입자들의 중심점간 거리를 화소(CCD 카메라의 pixel)단위로 계산하였으며, 화소의 좌표는 레이저 간섭계로 변위를 읽는 이송대를 이용하여 교정하였다. 기존의 측정방법을 개선하여 빠른 시간에 간편하게 측정하면서도 표준입자의 배율고정에 충분한 불확도를 얻을 수 있었다. 본 실험에는 NIST 인증물질인 3$\mu\textrm{m}$와 10$\mu\textrm{m}$ 폴리스티렌구(NIST SRM 1962, 1960)를 측정하였으며, 1%이하의 불확도(신뢰도 99% 수준)로써 NIST 결과와비교하였다.

• Journal of Welding and Joining
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• 제29권5호
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• pp.90-94
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• 2011

Ag metallic particles from nano-scale to submicron-scale are combined with organic solvent to provide fine circuits and interconnection. Ink-jet printing with Ag nano particle inks demonstrated the potentials of the new printed electronics technology. The bonding at the interface between the Ag wiring layer and the various substrates is very important. In this study, the details of interfaces in Ag wiring are investigated primarily by microstructure observation. By adjusting the materials and sintering conditions, nicely formed interfaces between Ag wiring and Cu, Au or organic substrates are achieved. In contrast, transmission electron microscope (TEM) image clearly shows interface debonding between Ag wiring and Sn substrate. Sn oxides are formed on the surface of the Sn plating. The formation of these is a root cause of the interface debonding.

• 한국산학기술학회논문지
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• 제18권2호
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• pp.95-101
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• 2017

본 논문에서는 복합재료로 만들기 위한 전처리 단계에서 수행한 사이징 제거 상태를 영상처리 알고리즘을 적용하여 수치적으로 나타내었고, 전자파 차폐 성능을 높이기 위해서 건식 공정 방식으로 니켈도금 탄소섬유를 제작하였다. 탄소섬유 제조에서 폴리머 종류로 감싸져 나온 사이징은 건식 코팅을 위해서는 제거해야 한다. 사이징이 제거된 상태를 주사 전자현미경(scanning electron microscope, SEM)으로 촬영한 이미지에서 탄소 섬유의 규칙적인 패턴, 즉 상관성을 구함으로써 수치적인 값으로 나타낼 수 있다. 사이징의 제거 방식은 용액, 압축 공기와 용액과 압축공기(하이브리드)로 제거한 SEM 영상에 대하여 제안된 방법을 적용한 결과 하이브리드 방식이 우수함을 확인 할 수 있었다. 그리고 사이징이 제거된 스프레딩 탄소 섬유 롤을 롤투롤 스퍼터 방식으로 니켈도금 탄소 섬유를 제작할 수 있었다. 제작된 30um, 40um과 100um 니켈코팅 탄소섬유에 대해서 전자파 차폐 성능을 측정하였다. 한국산업기술시험원에서 100um 니켈코팅 탄소섬유의 전자파 차폐 성능을 평가한 결과 최저 66.7(dB)에서 최고 73.2(dB)의 전자파 차폐 성능을 보였다. 이것은 구리의 전자파 차폐율과 유사하여 EV/HEV자동차의 케이블로 사용될 수 있다.

• 반도체디스플레이기술학회지
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• 제21권1호
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• pp.108-113
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• 2022

The deep-learning-based measurement method with the through-focus scanning optical microscopy (TSOM) estimated the size of the object using the classification. However, the measurement performance of the method depends on the number of subdivided classes, and it is practically difficult to prepare data at regular intervals for training each class. We propose an approach to measure the size of an object in the TSOM image using the deep-learning regression model instead of using classification. We attempted our proposed method to estimate the top critical dimension (TCD) of through silicon via (TSV) holes with 2461 TSOM images and the results were compared with the existing method. As a result of our experiment, the average measurement error of our method was within 30 nm (1σ) which is 1/13.5 of the sampling distance of the applied microscope. Measurement errors decreased by 31% compared to the classification result. This result proves that the proposed method is more effective and practical than the classification method.

• 한국정밀공학회지
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• 제25권11호
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• pp.52-57
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• 2008

We demonstrate the operation of an apparatus that we call the laser scanning confocal microscopy. It is valuable tool of the investigations for imaging process. We measured the thin metal structure through the SCM manufacture. Confocal microscopy offers several advantages including shallow depth of field, elimination of out-of-focus glare, and the ability to collect serial optical sections from thick specimens than conventional optical microscope. This research is manufactured of scanning confocal microscopy and after measured of metal materials structure.

• Fibers and Polymers
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• 제5권3호
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• pp.198-203
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• 2004

Composite films were prepared by casting the solution of polyacrylonitrile (PAN) and single wall nanotube (SWNT) in DMF subsequent to sonication. The SWNTs in the films are well dispersed as ropes with 20-30 nm thickness. Moreover, AFM surface image of the composite film displays an interwoven fibrous structure of nanotubes which may give rise to conductive passways and lead to high conductivity. The polarized Raman spectroscopy is an ideal characterization technique for identification and the orientation study of SWNT. The well-defined G-peak intensity at 1580 $cm^{-1}$shows a dependency on the draw ratio under cross-Nicol. The degree of nanotube orientation in the drawn film was measurable from the sine curve obtained by rotating the drawn film on the plane of cross-Nicol of polarized Raman microscope. The threshold loading of SWNT for electrical conductivity in PAN is found to be lower than 1 wt% in the composite film. The electrical conductivity of the SWNT/PAN composite film decreased with increasing of draw ratio due to the collapse of the interwoven fibrous network of the nanotubes with uniaxial orientation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.239.2-239.2
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• 2015

Graphene is a most interesting material due to its unique and outstanding properties. However, semi-metallic properties of graphene along with zero bandgap energy structure limit further application to optoelectronic devices. Recently, many researchers have shown that band gap can be induced in the Bernal stacked bilayer graphene. Several methods have been used for the controlled growth of the Bernal staked bilayer graphene, but it is still challenging to control the growth process. In this paper, we synthesize the large area Bernal stacked bilayer graphene using multi heating zone low pressure chemical vapor deposition (LPCVD). The synthesized bilayer graphenes are characterized by Raman spectroscopy, optical microscope (OM), scanning electron microscopy (SEM). High resolution transmission electron microscopy (HRTEM) is used for the observation of atomic resolution image of the graphene layers.

• Journal of the Optical Society of Korea
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• 제11권1호
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• pp.18-25
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• 2007

We present an ultrahigh-resolution full-field optical coherence tomography (FF-OCT) implemented with a white-light interference microscope and a detector array as an alternative OCT technique. The use of detector array allows the capture of two-dimensional en-face images in parallel without taking any lateral scanning process. The phase shifting interferometric technique with the sinusoidal phase modulation (SPM) is utilized to get the demodulated OCT images. The configuration of the system and the resolution of the obtained image are presented. The topographic images, taken with the implemented system, of a coin, an integrated circuit chip, and the tomographic images of an onion epithelium are demonstrated also. Axial and lateral spatial resolution of ${\sim}1.0{\mu}m$ and ${\sim}2.0{\mu}m$ are achieved with the system respectively.