• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.239.1-239.1
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• 2005

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.561-562
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• 2008

• 대한화학회지
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• 제66권2호
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• pp.75-77
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• 2022

• Applied Microscopy
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• 제39권1호
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• pp.41-48
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• 2009

본 연구는 색조화장품에 사용되는 진주광택안료의 특성을 주사전자현미경과 에너지분산분광분석기 및 열분석기를 사용하여 규명하였다. 본 연구에 사용된 인공합성 진주광택안료를 여성의 볼과 눈두덩 부위에 화장을 한 후 육안으로 관찰하였을 때 진주 광택안료는 보는 각도에 따라 흰색에서 보라색까지 다양한 색조로 빛을 반사하였다. 진주광택안료의 주사전자현미경 관찰 결과 안료는 얇은 판상의 다각형의 형태를 하고 있었으며 크기는 규격화된 모양이 아니고 다양하게 관찰되었다. 이런 조각의 크기는 약 $30{\mu}m$에서 $300{\mu}m$까지 측정되었고 안료 조각은 끝이 뾰족하거나 각진 상태로 존재하였다. 고배율의 주사전자현미경상에서 안료조각의 모서리 부위와 측면은 날카롭지 않은 타원형의 형태로 나타났으며 두께는 약 $9{\mu}m$로 측정되었다. 안료조각 표면은 직경이 약 60 nm의 이산화티탄 입자들에 의해서 피복되어 있었다. 진주광택안료의 에너지분산분석기를 사용하여 구성 원소 성분을 분석한 결과 안료의 표면은 O, Si, C, Na, Ca, Ti, Zn 등이 검출되었고 안료의 측면 부위도 동일한 성분들이 검출되었다. 이들 안료는 운모 티타니아(mica titania)로 확인되었다. 진주광택안료의 열분석 결과 초기 $100^{\circ}C$부터 $800^{\circ}C$까지 중량 감소는 큰 차이를 보이지 않았다. 열분석 결과 $115^{\circ}C$에서 1.1% 중량 감소를 하였고 $416^{\circ}C$에서 1.7% 감소하였으며 $797^{\circ}C$ 에서 1.9%의 중량이 감소된 것을 확인하였다.

• Applied Microscopy
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• 제51권
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• pp.19.1-19.7
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• 2021

The main purpose of this paper is the preparation of transmission electron microscopy (TEM) samples from the microsized powders of lithium-ion secondary batteries. To avoid artefacts during TEM sample preparation, the use of ion slicer milling for thinning and maintaining the intrinsic structure is described. Argon-ion milling techniques have been widely examined to make optimal specimens, thereby making TEM analysis more reliable. In the past few years, the correction of spherical aberration (Cs) in scanning transmission electron microscopy (STEM) has been developing rapidly, which results in direct observation at an atomic level resolution not only at a high acceleration voltage but also at a deaccelerated voltage. In particular, low-kV application has markedly increased, which requires a sufficiently transparent specimen without structural distortion during the sample preparation process. In this study, sample preparation for high-resolution STEM observation is accomplished, and investigations on the crystal integrity are carried out by Cs-corrected STEM.

• The Journal of Advanced Prosthodontics
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• 제6권5호
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• pp.387-394
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• 2014

PURPOSE. Topographic analysis of treated ceramics provides qualitative information regarding the surface texture affecting the micromechanical retention and locking of resin-ceramics. This study aims to compare the surface microstructure following different surface treatments of feldspathic porcelain. MATERIALS AND METHODS. This in-vitro study was conducted on 72 porcelain discs randomly divided into 12 groups (n=6). In 9 groups, feldspathic surfaces were subjected to sandblasting at 2, 3 or 4 bar pressure for 5, 10 or 15 seconds with $50{\mu}m$ alumina particles at a 5 mm distance. In group 10, 9.5% hydrofluoric acid (HF) gel was applied for 120 seconds. In group 11, specimens were sandblasted at 3 bar pressure for 10 seconds and then conditioned with HF. In group 12, specimens were first treated with HF and then sandblasted at 3 bar pressure for 10 seconds. All specimens were then evaluated under scanning electron microscopy (SEM) at different magnifications. RESULTS. SEM images of HF treated specimens revealed deep porosities of variable sizes; whereas, the sandblasted surfaces were more homogenous and had sharper peaks. Increasing the pressure and duration of sandblasting increased the surface roughness. SEM images of the two combined techniques showed that in group 11 (sandblasted first), HF caused deeper porosities; whereas in group 12 (treated with HF first) sandblasting caused irregularities with less homogeneity. CONCLUSION. All surface treatments increased the surface area and caused porous surfaces. In groups subjected to HF, the porosities were deeper than those in sandblasted only groups.

• Parasites, Hosts and Diseases
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• 제51권2호
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• pp.243-246
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• 2013

It is known that physicochemical conditions (e.g., pH, temperature, and ionic strength) affect the size of trichomonads. In this study, the sizes of 4 isolates of Trichomonas vaginalis cultured for more than a year (called "old T") and 3 isolates freshly isolated from vaginitis cases (called "fresh T") were compared by scanning electron microscopy. Although the fresh T had shorter body length, body width, and flagellar length than old T, total length (about $26{\mu}m$), including body length, flagella length, and axostyle length was almost the same in the 2 groups. A striking difference was observed between the axostyles of the 2 groups; the axostyle length of the fresh T ($8.2{\mu}m$) was more than twice as long as that of the old T ($4.0{\mu}m$). However, in several parasitology textbooks, the length of T. vaginalis is said to vary widely from 7 to $32{\mu}m$, and its undulating membrane is said to extend about half way (53.5%) to the posterior end of the body. On the other hand, in our study, the undulating membrane was observed to extend more than 3/4 of the body length (72.1%) in old T, whereas in fresh T it could not be measured. Taken together, we suggest that T. vaginalis averages 26 (21-32) ${\mu}m$ in total length, with 9.5 (7.4-11.4) ${\mu}m$ of body length and 6.8 (5.3-7.7) ${\mu}m$ of width, and its undulating membrane extending 3/4 of its body length. Therefore, these findings may provide useful information for morphological characteristics of T. vaginalis.

• Restorative Dentistry and Endodontics
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• 제29권3호
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• pp.273-280
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• 2004

The purpose of this study was to evaluate the etching effects and bond strength of total etching and self-etching adhesive system on unground enamel using scanning electron microscopy and microtensile bond strength test. The buccal coronal unground enamel from human extracted molars were prepared using low-speed diamond saw. Scotchbond Multi-Purpose (group SM). Clearfil SE Bond (group SE), or Adper Prompt L-Pop (group LP) were applied to the prepared teeth. and the blocks of resin composite (Filtek Z250) were built up incrementally. Resin tag formation was evaluated by scanning electron microscopy. after removal of enamel surface by acid dissolution and dehydration. For microtensile bond strength test. resin-bonded teeth were sectioned to give a bonded surface area of $1\textrm{mm}^2$. Microtensile bond strength test was perfomed. The results of this study were as follows. 1. A definite etching pattern was observed in Scotchbond Multi-Purpose group. 2. Self-etching groups were characterized as shallow and irregular etching patterns. 3. The results (mean) of microtensile bond strength were SM: 26.55 MPa, SE: 18.15 MPa, LP: 15.57 MPa. SM had significantly higher microtensile bond strength than 8E and PL (p < 0.05). but there was no significant differance between SE and PL.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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• pp.111-114
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• 1998

Lithium Niobate {{{{ { LiNbO}_{ 3} }}}} single crystals grown by Czichralski method at the congruent composition, have ferroelectric microdomains. These microdomins were investigated by chemical etching with hydrofluoric acid (HF) AND NITRIC ACID ({{{{ { HNO}_{3 } }}}}), and by us ing optical microscopy, scanning electron microscopy and atomic force microscopy

• 대한기계학회논문집A
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• 제39권1호
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• pp.1-9
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• 2015

이 논문은 SEM(Scanning Electron Microsopy) 경통부에서 전자빔의 집속특성을 최적화하기 위한 방법을 다루고 있다. SEM 에서 물체 표면을 확대하기 위해서는 경통부를 지나는 전자빔을 효과적으로 집속하여 표면에 충돌하는 프로브 직경을 줄이는 것이 중요하다. 이 전자빔의 집속정도를 나타내는 지표가 반배율이다. 본 연구는 전자빔의 집속특성을 효과적으로 구현하기 위해 그에 영향을 끼치는 경통부의 설계 인자들을 렌즈 해석과 광선 추적을 통해 알아본다. 이 결과를 근거로 민감도 분석을 수행하여 설계 인자들이 빔의 집속에 끼치는 영향의 정도를 정량적으로 비교해 볼 수 있다. 이러한 전자빔의 특성에 따른 설계 인자의 분석은 경통부 설계에 있어 중요한 기초 정보로 활용될 수 있다.