• Applied Microscopy
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• 제2권1호
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• pp.39-46
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• 1972

There are many kinds of microscopes suitable for general studies; optical microscopes(OM), conventional transmission electron microscopes (TEM), and scanning electron microscopes(SEM). The optical microscopes and the conventional transmission electron microscopes are very familiar. The images of these microscopes are directly formed on an image plane with one or more image forming lenses. On the other hand, the image of the scanning electron microscope is formed on a fluorescent screen of a cathode ray tube using a scanning system similar to television technique. In this paper, the features and some applications of the scanning electron microscope will be discussed briefly. The recently available scanning electron microscope, combining a resolution of about $200{\AA}$ with great depth of field, is favorable when compared to the replica technique. It avoids the problem of specimen damage and the introduction of artifacts. In addition, it permits the examination of many samples that can not be replicated, and provides a broader range of information. The scanning electron microscope has found application in diverse fields of study including biology, chemistry, materials science, semiconductor technology, and many others. In scanning electron microscopy, the secondary electron method. the backscattererd electron method, and the electromotive force method are most widely used, and the transmitted electron method will become more useful. Change-over of magnification can be easily done by controlling the scanning width of the electron probe. It is possible. to continuously vary the magnification over the range from 100 times to 1.00,000 times without readjustment of focusing. Conclusion: With the development of a scanning. electron microscope, it is now possible to observe almost all-information produced through interactions between substances and electrons in the form of image. When the probe is properly focused on the specimen, changing magnification of specimen orientation does not require any change in focus. This is quite different from the conventional transmission electron microscope. It is worthwhile to note that the typical probe currents of $10^{-10}$ to $10^{-12}\;{\AA}$ are for below the $10^{-5}$ to $10^{-7}\;{\AA}$ of a conventional. transmission microscope. This reduces specimen contamination and specimen damage due to heatings. Outstanding features of the scanning electron microscope include the 'stereoscopic observation of a bulky or fiber specimen in high resolution' and 'observation of potential distribution and electromotive force in semiconductor devices'.

• Applied Microscopy
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• 제51권
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• pp.1.1-1.2
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• 2021

We demonstrate a fabrication of an atomically controlled single-crystal heart-shaped nanostructure using a convergent electron beam in a scanning transmission electron microscope. The delicately controlled e-beam enable epitaxial crystallization of perovskite oxide LaAlO₃ grown out of the relative conductive interface (i.e. 2 dimensional electron gas) between amorphous LaAlO₃/crystalline SrTiO₃.

• 식물조직배양학회지
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• 제22권6호
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• pp.323-327
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• 1995

미나리의 체세포 배발생 과정을 해부학적으로 구명하기 위하여 배발생 기원세포와 캘러스를 광학현미경 및 전자현미경으로 관찰한 결과, 배발생 세포는 hematoxylin에 짙은 보라색으로, 비배발생 세포는 safranin에 적색으로 염색되어 광학현미경하에서 쉽게 구별할 수 있었다. 배발생 캘러스는 많은 수의 원배 및 발육중인 배, 비배발생 세포 등으로 구성되어 있었다. 체세포 배발생은 발육 중인 배나 세포괴의 표피세포에 위치한 배발생 세포의 하나가 분열하거나 세포괴내의 비배발생 세포속에 묻혀 있는 배발생 세포가 분열하여 일어났다. 배발생 과정은 항상 일정한 형태는 아니지만 단세포로부터 일정한 segmentation 과정를 거쳐서 배발생이 진행되는 것으로 나타났다. 투과전자현미경에 의한 관찰에서 배발생 세포는 비배발생 세포에 비하여 세포질이 조밀하고 핵이 대형이며 amyloplast, 인지질체 및 세포소기 관들이 많으며 액포가 없거나 매우 작았다. 이들 세포들은 두터운 세포벽에 의하여 주위의 비배발생 세포와 분리되어 있으며 세포윤곽은 둥글었다. 주사전자현미경으로 관찰한 배발생캘러스는 외부가 그물이 씌워진 형태의 구형의 다양한 크기의 배들과 비교적 크기가 큰 비배발생 세포들이 혼재하였다. 한편 비배발생능 캘러스는 구성세포가 크고 외부에는 gelatin같은 물질로 덮여 있었다.

• 한국식품영양과학회지
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• 제29권6호
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• pp.1112-1115
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• 2000

• 한국전자현미경학회:학술대회논문집
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• 한국현미경학회 2001년도 제32차 추계학술대회
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• pp.18-22
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• 2001

A technique to characterize specific site of materials using a combination of a dedicated focused ion beam system(FIB), and Intermediate-voltage scanning transmission electron microscope(STEM) or transmission electron microscope(TEM) equipped with a scanning electron microscope(SEM) unit has been developed. The FIB system is used for preparation of electron transparent thin samples, while STEM or TEM is used for localization of a specific site to be milled in the FIB system. An FIB-STEM(TEM) compatible sample holder has been developed to facilitate thin sample preparation with high positional accuracy Positional accuracy of $0.1{\mu}m$ or better can be achieved by the technique. In addition, an FIB micro-sampling technique has been developed to extract a small sample directly from a bulk sample in a FIB system These newly developed techniques were applied for the analysis of specific failure in Si devices and also for characterization of a specific precipitate In a metal sample.

• 한국전기전자재료학회논문지
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• 제36권4호
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• pp.326-331
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• 2023

The utilization of scanning transmission electron microscopy (STEM) in conjunction with cathodoluminescence (CL) has emerged as a valuable tool for the investigation of material optical properties. In recent years, this technique has facilitated significant advancements in the fields of plasmonics and quantum emitters by surpassing prior technical restrictions. The review commences by providing an outline of the diverse STEM-CL operating modes and technical aspects of the instrumentation. The review explains the fundamental physics of light production under electron beam irradiation and the physical basis for interpreting STEM-CL experiments for different types of excitations. Additionally, the review compares STEM-CL to other related techniques such as scanning electron microscope CL, photoluminescence, and electron energy-loss spectroscopy.

• Nuclear Engineering and Technology
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• 제44권5호
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• pp.491-500
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• 2012

The dissimilar metal joints welded between Ni-based alloy, Alloy 690 and low alloy steel, A533 Gr. B with Alloy 152 filler metal were characterized by using optical microscope, scanning electron microscope, transmission electron microscope, secondary ion mass spectrometry and 3-dimensional atom probe tomography. It was found that in the weld root region, the weld was divided into several regions including unmixed zone in Ni-base alloy, fusion boundary, and heat-affected zone in the low alloy steel. The result of nanostructural and nanochemical analyses in this study showed the non-homogeneous distribution of elements with higher Fe but lower Mn, Ni and Cr in A533 Gr. B compared with Alloy 152, and the precipitation of carbides near the fusion boundary.

• 공업화학
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• 제25권5호
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• pp.463-467
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• 2014

본 연구에서는 팽창흑연의 함량 변화를 달리하여 제조한 팽창흑연/에리스리톨 복합체의 열적거동에 관하여 고찰하였다. 팽창흑연이 도입된 팽창흑연/에리스리톨 복합체의 표면 및 구조특성은 scanning electron microscope (SEM), transmission electron microscope (TEM), 그리고 X-ray diffraction (XRD)를 이용하여 관찰하였으며, 열적특성은 differential scanning calorimetry (DSC)와 thermal conductivity (TC)를 이용하여 분석하였다. 실험 결과 팽창흑연의 함량이 증가함에 따라 팽창흑연/에리스리톨 복합체의 열전도도가 증가하였으며, 반면에 잠열은 팽창흑연의 존재 하에 약간 감소하였다. 결론적으로 팽창흑연은 상변이 물질의 높은 열 전달성능 및 열 저장능력을 향상시키는데 적합한 소재라 판단된다.

• 대한의생명과학회지
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• 제8권1호
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• pp.13-20
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• 2002

Asadisulphide were purified from Ferrula assafoetida by organic solvent extraction and chromatography. Since ethyl acetate extracts of F. assafoetida has the strongest inhibitory effects on adherence of HL-60 cells, it was reextracted with ethyl acetate, hexane, and ethyl ether and chromatographed three times to isolate asadisulphide. HL-60 cells were grouped into untreated control, TPA-treated, asadisulphide-teated and TPA＋asadisulphide-treated groups, and structural changes of these cells were observed using light microscope, scanning electron microscope and transmission electron microscope to examine the inhibitory effects of asadisulfide on the TPA-induced adherence of HL-60 cells. Light microscopic observations showed that asadisulphide has inhibitory effects on the cell aggregation, extention of cytoplasmic processes and inhibition of substrate adhesion of HL-60 cells. Using scanning and transmission electron microscope, it was observed that cell surfaces and several ultrastructures of TPA-treated HL-60 cell were different from control group, while there were no remarkable differences between asadisulphide-treated and TPA＋asadisulphide-treated group. These results could suggest that asadisulphide has the inhibitory effects on the TPA-induced structural changes of HL-60 cells.

• 펄프종이기술
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• 제48권1호
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• pp.5-18
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• 2016

Electron microscopy is an important investigation and analytical method for the morphological characterization of various cellulosic materials, such as micro-crystalline cellulose (MCC), microfibrillated cellulose (MFC), nanofibrillated cellulose (NFC), and cellulose nanocrystals (CNC). However, more accurate morphological analysis requires high-quality micrographs acquired from the proper use of an electron microscope and associated sample preparation methods. Understanding the interaction of electron and matter as well as the importance of sample preparation methods, including drying and staining methods, enables the production of high quality images with adequate information on the nanocellulosic materials. This paper provides a brief overview of the micro and nano structural analysis of cellulose, as investigated using transmission and scanning electron microscopy.