• 한국세라믹학회지
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• 제42권10호
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• pp.685-690
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• 2005

Pb(Zr,Ti)$O_{3}$Pb($Mn_{1/3}$$Nb_{2/3}$)$O_{3}$ powder was successfully synthesised by high-energy milling method, and the behavior of low­temperature sintering and piezoelectrical properties of Pb(Zr,Ti)$O_{3}$-Pb($Mn_{1/3}$$Nb_{2/3}$)$O_{3}$ ceramics were investigated as a function of mechanical alloying time. In order to confirm whether the Perovskite phase in this composition was formed by mechanical activation technique or not, we performed X-Ray Diffraction pattern analysis (XRD). The microstructure for the sintered samples were characterized using a Scanning Electronic Microscope (SEM). And the piezoelectrical properties ($k_{p}$ and $Q_{m}$) of the sintered samples was measured using HP 4194A impedance analyzer.

• 한국광물학회지
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• 제19권2호
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• pp.111-121
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• 2006

금속 조합을 이용하여 배관내벽에 형성된 스케일의 제거 및 억제 가능성과 광물학적 특성을 연구하기 위하여 주사전자현미경, 방안실체현미경, 선회절분석, 스케일 제거실험을 실시하였다. 배관내벽에 생성된 스케일은 대부분 철광물로 구성되어있으며 약간의 Si와 Ca 광물을 포함하고 있다. 배관내벽의 스케일을 제거하는 데 내부 금속을 Mg, 외부금속을 황동으로 실험하였을 때 가장 좋은 효과를 나타낸다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 춘계학술발표회 논문집
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• pp.151-159
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• 2003

This study presents method for self-calibration of the SEM(Scanning Electron Microscope) stereo image using the standard microprobe with same grid pattern and using parallel and central perspective projection equation. Result showed that parallel projection method is more suitable for standard microprobe. The maximum error of 3D coordinates acquired by this method did not exceed 5 $\mu\textrm{m}$, and DSM(Digital Surface Model) for three dimensional measurement of the rock sample was generated by the digital photogrammetry. This result can be used for quantification of micro scale change of shape and analysis of the micro morphology of rock due to weathering.

• 한국결정성장학회지
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• 제24권2호
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• pp.54-58
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• 2014

PVT(물리 기상 이동법, Physical Vapor Transport) 법을 적용하여 질화알루미늄(AlN, Aluminum Nitride) 단결정을 성장하였으며, 성장된 결정의 결정성과 성장 온도에 따른 상에 대하여 고찰하였다. 성장된 단결정은 광학현미경을 이용하여 결정의 상을 관찰하였고, 관찰된 결과를 비교 분석하여 본 실험에 적용된 성장 장치에서의 최적의 성장 온도 조건을 설정할 수 있었다. 본 연구에서는 AlN 단결정 성장 결과를 비교 고찰하여 보고하고자 한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.158-163
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• 2001

Operators suffer much difficulty in manipulating micro/nano-sized objects without the assistance of human interfaces, due to the scaling effects in micro/nano world. This paper presents a micro manipulation system based on the teleoperation techniques which enables the operators to manipulate the objects with ease by transferring both human motion and manipulation skill to a micromanipulator. An experimental setup consisting of a micromanipulator operated under stereo-microscope with the help of intelligent user interface provides a tool that can be used to visualize and manipulate micro-sized 3D objects in a controlled manner. The key features of a micro manipulation system and control strategies using teleoperation techniques for handling micro objects are presented. Experimental results demonstrate the feasibility of this system in precisely controlling trapping and manipulation of micro objects based on teleoperation techniques.

• 한국산업보건학회지
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• 제19권3호
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• pp.213-232
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• 2009

This document was prepared to review and summarize the analytical methods for airborne and bulk asbestos. Basic principles, shortcomings and advantages for asbestos analytical instruments using phase contrast microscopy(PCM), polarized light microscopy(PLM), X-ray diffractometer (XRD), transmission electron microscopy(TEM), scanning electron microscopy(SEM) were reviewed. Both PCM and PLM are principal instrument for airborne and bulk asbestos analysis, respectively. If needed, analytical electron microscopy is employed to confirm asbestos identification. PCM is used originally for workplace airborne asbestos fiber and its application has been expanded to measure airborne fiber. Shortcoming of PCM is that it cannot differentiate true asbestos from non asbestos fiber form and its low resolution limit ($0.2{\sim}0.25{\mu}m$). The measurement of airborne asbestos fiber can be performed by EPA's Asbestos Hazard Emergency Response Act (AHERA) method, World Health Organization (WHO) method, International Standard Organization (ISO) 10312 method, Japan's Environmental Asbestos Monitoring method, and Standard method of Indoor Air Quality of Korea. The measurement of airborne asbestos fiber in workplace can be performed by National Institute for Occupational Safety and Health (NIOSH) 7400 method, NIOSH 7402 method, Occupational Safety and Health Administration (OSHA) ID-160 method, UK's Health and Safety Executive(HSE) Methods for the determination of hazardous substances (MDHS) 39/4 method and Korea Occupational Safety and Health Agency (KOSHA) CODE-A-1-2004 method of Korea. To analyze the bulk asbestos, stereo microscope (SM) and PLM is required by EPA -600/R-93/116 method. Most bulk asbestos can be identified by SM and PLM but one limitation of PLM is that it can not see very thin fiber (i.e., < $0.25{\mu}m$). Bulk asbestos analytical methods, including EPA-600/M4-82-020, EPA-600/R-93/116, OSHA ID-191, Laboratory approval program of New York were reviewed. Also, analytical methods for asbestos in soil, dust, water were briefly discussed. Analytical electron microscope, a transmission electron microscope equipped with selected area electron diffraction (SAED) and energy dispersive X-ray analyser(EDXA), has been known to be better to identify asbestiform than scanning electron microscope(SEM). Though there is no standard SEM procedures, SEM is known to be more suitable to analyze long, thin fiber and more cost-effective. Field emission scanning electron microscope (FE-SEM) imaging protocol was developed to identify asbestos fiber. Although many asbestos analytical methods are available, there is no method that can be applied to all type of samples. In order to detect asbestos with confidence, all advantages and disadvantages of each instrument and method for given sample should be considered.

• International Journal of Concrete Structures and Materials
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• 제1권1호
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• pp.75-81
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• 2007

The concrete pavement of the Seohae Highway in Korea has suffered from serious distress, only four to seven years after construction. Deterioration due to Alkali-Silica Reaction (ASR) has seldom been reported per se in Korea, because the aggregate used for the cement concrete has been considered safe against alkali-silica reaction so far. The purpose of this study is to examine the deterioration caused by an alkali-silica reaction of concrete pavement in Korea. The investigation methods included visual inspection and Automatic Road Analyzer (ARAN) analysis of surface cracks, coring for internal cracks, stereo microscopic analysis, scanning electronic microscope (SEM) analysis, and electron dispersive X-ray spectrometer (EDX) analysis. The results are presented as follows: the crack pattern of the concrete pavement in Korea was longitudinal cracking, map cracking or D-cracking. Local areas of damage were noticed four to five years after construction. The cracks started from edges or joints and spread out to slabs. The most intensive cracking was observed at the intersection of the transverse and longitudinal joints. Where cracking was the most intense, pieces of concrete and aggregate had spalled away from top surface and joint interface area. The progress of deterioration was very fast. The reaction product of alkali-silica gel was clearly identified by its generally colorless, white, or very pale yellow hue seen through a stereo optical microscopy. The typical locations of the reaction product were at the interface between aggregate and cement paste in a shape of a rim, within aggregate particles in the cracks, and in the large void in the cement paste. Most of the white products were found at interface or internal aggregates. SEM and EDX analysis confirmed that the white gel was a typical reaction product of ASR. The ASR gel in Korea mainly consisted of Silicate (Si) and Potassium (K) from the cement. The crack in the concrete pavement was caused by ASR. It seems that Korea is no longer safe from alkali-silica reaction.

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.106-120
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• 1991

The main purpose of this study was to investigate the possibility of obstruction of dentinal tubules through irradiation of the $CO_2$ laser on the dentin surface. For this study, 104 extracted caries - free premolars and molars were grinded their mesial or distal surface to expose dentin completly. And these specimens were divided into three Groups. Group I : those with their smear layer not removed and Group IT : those with their smear layer removed, were irradiated by the $CO_2$ laser(SPACE LASER - $CO_2$ VEGA 25) at five different energy levels ranging 4 - 20J/$cm^2$, and all specimens were observed with scanning eletron microscope (Hitachi S - 450). Group m was divided into 2 sub - groups: one with smear layer, another one without and those were irradiated with $CO_2$ laser of the same condition as Group I & II. All specimens were immersed in, $37^{\circ}C$, 0.5% methylene blue solution for 48 hours after 100 times of thermocycling at $4^{\circ}C$ and $60^{\circ}C$, and were observed with stereo -light microscope (Olympus SZH - ILLD) to evaluate dye penetration. The following results were obtained; 1. The dentinal tubules were obstructed through laser irradiation. 2. The dentinal tubules were still obstructed after treatment of 10% HCl/2sec., then it was proved that acid resistance of detin surface was also increased. 3. The Group of laser irradiation showed less dye penetration than control Group. 4. The smear layer hardly affected obstruction of the dentinal tubules through laser irradiation.

• 한국어류학회지
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• 제28권4호
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• pp.223-228
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• 2016

한국산 대륙송사리 Oryzias sinensis의 후각기관을 실체현미경과 광학현미경을 이용하여 해부 및 조직 화학적 특징들을 조사하였다. 전체적 구조에서 후각기관은 두부의 주둥이 위에 한 쌍으로 존재하였으며 다소 떨어져있는 전비공과 후비공, 한 개의 비강, 한 개의 비낭으로 구성되었다. 비강내 상피는 감각상피와 비감각상피층으로 구분되었다. 감각상피는 후감각세포, 지지세포, 기저세포 그리고 공포들로 구성되었다. 비감각상피는 층상상피 세포, 산성과 중성 점액세포들로 구성되었다. 비낭의 상피층은 층상상피세포와 배상세포들로 구성되었다. 결과적으로 이러한 대륙송사리의 후각기관의 해부 및 조직화학적 특징들은 농경지에서의 정체되고 오염되어있는 수환경을 반영하는 것으로 사료된다.

• 식물분류학회지
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• 제34권4호
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• pp.273-285
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• 2004

Lycopus속 15종의 화판(petal)과 악편(sepal)의 미세형태를 주사전자현미경과 실체현미경으로 관찰하여 그 분류학적 유용성을 검토하였다. Lycopus속 분류군들의 화관과 악에 분포하는 모용과 선모는 단세포 원주모(unicellular cylindrical trichome), 표면에 돌기가 있는 단세포 모용(unicellular trichome with papillae), 다세포 모용(simple multicellular trichome), 두상선모(capitate glandular trichome) 및 방패형 선모(peltate glandular trichome) 등 5 종류로 나타났으며, 모용의 종류, 분포, 밀도가 분류군마다 다르게 나타났다. 화관 안쪽면에 단세포 원주모(unicellular cylindrical trichome)의 분포 정도가 각 분류군마다 다르게 나타나, 그 분포 부위에 따라 4가지 유형으로 나눌 수 있었다. 악(calyx)은 악편이 갈라지는 정도와 악편 정단(apex)의 모양으로 4가지 형태로 구분할 수 있었다. 화판과 악편의 안쪽 빛 바깥면을 구성하는 세포의 형태는 그 위치와 분류군에 따라 다양하게 나타났다. 끝으로 관찰된 Lycopus속의 화판 및 악편 미세형태를 검토한 결과 종간 식별에 유용하였다.