• Applied Microscopy
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• 제45권4호
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• pp.214-217
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• 2015

This study introduces metal coating as an effective sample preparation method to remove charge-up caused by the shadow effect during field emission scanning electron microscope (FE-SEM) analysis of dynamic structured samples. During a FE-SEM analysis, charge-up occurs when the primary electrons (input electrons) that scan the specimens are not equal to the output electrons (secondary electrons, backscattered electrons, auger electrons, etc.) generated from the specimens. To remove charge-up, a metal layer of Pt, Au or Pd is applied on the surface of the sample. However, in some cases, charge-up still occurs due to the shadow effect. This study developed a coating method that effectively removes charge-up. By creating a converted sample stage capable of simultaneous tilt and rotation, the shadow effect was successfully removed, and image data without charge-up were obtained.

• Carbon letters
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• 제2권3_4호
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• pp.202-211
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• 2001

• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.930-934
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• 2006

This paper reports a change of carbon nanotubes(CNTs) properties by post-treatment process after growth of CNTs. CNTs were treated by thermal method and solution method, and then investigated in detail using field emission scanning electron microscopy(FE-SEM), high resolution transmission scanning electron microscopy(HR-TEM), RAMAN spectroscopy, and Fourier Transform Infrared Spectrometer (FT-IR). FT-IR spectra showed that the amount of hydroxyl generated on surface of CNTs were changed with post-treatment condition. FE-SEM and TEM images were shown CNTs diameter and density variations were dependent with their treatment conditions. RAMAN spectroscopy was shown that carbon nanotubes structure vary with treatment conditions.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.346-346
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• 2011

최근 들어 나노스케일에서의 자구체(magnetic domain)에 대한 연구가 매우 활발하게 진행되고 있다. 현재 국내에서 자성 나노구조에 대한 연구가 매우 활발하게 진행 되고 있는 반면에 나노자성이미지를 연구 할 수 있는 장비는 매우 미비한 상황이다. 이러한 자성 이미징을 연구하는데 있어 가장 핵심 적인 장비가 SEMPA(Scanning Electron Microscopy with Polarization Analysis)이다. 국내에서 자성나노구조의 자화와 형상을 동시에 측정 할 수 있는 장비는 한국표준과학연구원에서 개발된 W-filament source를 사용한 SEMPA가 유일하다. 일반적으로 SEM의 경우 고에너지 빔의 전자 빔을 주사 시키고 이때 발생되는 이차 전자의 수를 2차원상의 영역에 따라 달라지는 비로 형상을 측정 하게 된다. 이때 전자의 수 뿐만 아니라 이들의 spin polarization을 측정 할 수 있다면 형상뿐 만 아니라 표면에서의 스핀 상태를 동시에 측정할 수 있게 된다. 기개발된 W-filament source를 이용한 SEMPA는 field emission source에 비하여 전자빔의 세기가 약하며 이차 전자의 수도 적어 spin polarization 감도가 현저히 떨어진다. 또한 초고진공(1x10-10torr)에서 사용할 수 없어 측정시료의 contamination을 방지 할 수 없다. 이러한 문제점들을 보안하기 위하여 field emission source를 이용한 FE-SEMPA를 개발 중이다. 본 연구에서는 설계 및 전산시늉등의 연구결과와 진행사항을 발표하고자 한다. 아울러 W-filament를 사용한 SEMPA의 연구결과에 대한 논의를 할 예정이다.

• 분석과학
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• 제21권6호
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• pp.553-561
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• 2008

MWCNT 와 여러 가지 티탄 알콕사이드 전구체를 사용하여 $CNT/TiO_2$ 복합제를 제조하였다. 이들 복합체들은 SEM, FE-SEM, XRD, EDX 및 UV-vis 분광기를 사용하여 종합적으로 분석하였다. UV 조사하에서 MB모델 수용액의 변이에 대한결과로부터 제조된 물질에 대한 광활성을 시험하였다. 마지막으로 MB 제거 실험의 결과에 따르면, 시료 CTOS의 경우 시료 CTIP 및 CTPP의 경우보다 우수한 MB제거 효과를 나타내었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.83-83
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• 2011

본 연구에서는 p-type Si (100) 위에 분자선 에피택시 성장방법으로 ZnO 완충층이 삽입된 ZnO 박막을 성장시켰다. ZnO 완충층은 Zn 셀 셔터의 열림/닫힘을 반복하는 성장 멈춤법으로 성장되었다. Zn 셀 셔터의 열림 시간은 4분, 2분, 1분이며 닫힘 시간은 2분으로 동일하게 유지하였다. 이러한 과정은 각각 5, 10, 20회로 반복되었으며 ZnO 완충층을 성장한 후 ZnO 박막은 기존의 분자선 에피택시 방법으로 성장되었다. ZnO 박막의 구조적, 광학적 특성은 field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), photoluminescence (PL)로 조사하였다. SEM 측정결과 성장 멈춤 횟수가 증가함에 따라 ZnO 박막의 표면은 섬(island) 구조에서 미로(maze) 구조로 변화하였고, XRD 측정결과 full-width at half-maximum (FWHM) 이 감소하고 결정립 크기(grain size)가 증가하였다. 그리고 PL 측정결과 성장 멈춤 횟수가 증가함에 따라 near-band-edge emission (NBE) 피크의 세기가 증가하였고 deep-level emission (DLE) 피크의 위치는 오렌지 발광에서 녹색 발광으로 청색편이(blue-shift)하였다.

• 한국지반환경공학회 논문집
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• 제20권11호
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• pp.5-10
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• 2019

본 연구에서는 장파장에서 감응하는 광촉매를 개발하기 위하여 상용화된 $TiO_2$에 Ag를 도핑하여 제조하였으며 광촉매 효율을 향상시키기 위하여 귀금속의 분산을 증대시키는 마이크로에멀젼 방법을 이용하였다. 제조된 $Ag/TiO_2$의 물리적 특성은 SEM(Scanning Electron Microscopy), FE-TEM(Field Emission Transmission Electron Microscopy), DRS(Diffuse Reflectance Spectroscopy)를 통해 분석하였다. RO 16(Reactive Orange 16)에 대한 광촉매의 제거 효율은 25ppm의 RO 16을 대상으로 UV-A 영역(365nm)에서 수행하였다. Ag의 도핑방법에 의한 광촉매 효율을 비교하기 위해 볼밀링 및 딥코팅 방법으로 제조하여 광촉매 효율을 분석하였으며 광촉매 효율에 대한 Ag 및 계면활성제 함량에 대한 최적화를 진행하였다. 도핑방법에 따른 RO 16 제거효율 분석 결과, 마이크로에멀젼 방법으로 제조한 $Ag/TiO_2$의 RO 16 제거효율이 가장 높았으며 Ag 함량 2wt%, 계면활성제 0.5g에서 가장 높은 제거효율을 보였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.112-112
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• 2015

The purposed of this work was to determine nanotube shape variation on the Ti-xNb alloys with alloying elements and applied potentials. Samples were prepared by arc melting, followed by followed by homogenization for 12 hr at $1000^{\circ}C$ in argon atmosphere. This study was evaluated the phase and microstructure of Ti-xNb alloys using an X-ray diffraction (XRD) and optical microscopy (OM). The morphology of the samples was investigated with a field-emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). The nanotube on the alloy surface was formed in 1 M $H_3PO_4$ with small additions of NaF 0.8 wt.%. All anodization treatments were carried out using a scanning potentiostat (Model 362, EG&G, USA) at constant voltage 30 V for 120 min, respectively. The morphology of the samples was investigated with a field-emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Surface characteristics of nanotbue formed on Ti-xNb alloys was investigated by potentiodynamic test and potentiostatic in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. It was observed that the changed ${\alpha}$ phase to ${\beta}$ phase with Nb content.

• Asian Journal of Atmospheric Environment
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• 제6권4호
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• pp.275-280
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• 2012

To understand the effect of aerosols on the growth and physiological conditions of trees in forests, it is important to know the state of aerosols that are deposited on the surface of the leaves or needles. In this study, we developed methods of visualization of submicron-sized aerosols that were artificially deposited from the gas-phase or liquid phase onto tree leaves or needles in trees. Firstly, we used field-emission scanning electron microscopy (FE-SEM) to observe black carbon (BC) particles that were artificially sprayed onto the leaves or needles. The distribution of BC particles deposited on the leaves and needles were distinguished based on the size and morphological features of the particles. The distribution and agglomerates size of BC particles differed between two spraying methods of BC particles employed. Secondly, we tried to visualize gold (Au) particles that were artificially sprayed onto the leaves using energy dispersive X-ray spectrometry (EDX) coupled to FE-SEM. We detected the Au particles based on the characteristic X-ray spectrum, which was secondarily generated from the Au particles. In contrast to the case of BC particles, the Au particles did not form agglomerates and were uniformly distributed on the leaf surfaces. The present results show that our methods provide useful information of adsorption and/or behavior of fine particles at the submicron level on the surface of the leaves.

• 대한약침학회지
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• 제25권4호
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• pp.382-389
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• 2022

Objectives: The Korean Industrial Standard (KS) for sterile acupuncture needles was established in 2009 based on research on the quality control of acupuncture needles. We aimed to determine the quality of acupuncture needles available in South Korea in 2021 by examining their surface condition and chemical composition using field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS). Methods: In South Korea, there are 23 brands of acupuncture needles, and we examined 10-15 needles from each brand, resulting in a total of 285 needles. The microstructures of the needles were assessed by SEM. Using SEM images, we evaluated the acupuncture needle tips for the following defects/aspects: scratches, lumps, detached coating, bent tip, and tip sharpness. EDS was used to determine the chemical composition of the selected acupuncture needles. Results: Overall, 88.4% of 285 needles were found to have at least one type of abnormality. The most frequently observed abnormalities were scratches and dents on the surface (68.1%), followed by detached coating (63.2%), and lumps (61.8%); blunt tips were observed in about 24% of them. Of 252 needles with at least one defect, 86.9% had two or more types of defects. The ratio of the number of needles with any defect to that of needles without any defect varied among brands, ranging from 50% to 100%. Regarding foreign materials, higher proportions of Si and O were observed on the needles, indicating incomplete or detached silicone coating. Conclusion: The quality of acupuncture needles varied among brands, suggesting that further improvements can be made through various inspection methods.