• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.74-74
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• 1999

TEM(투과전자현미경, Transmission Electron Microscop)은 결정재료뿐 아니라 비정질 재료까지도 원자단위의 구조를 연구하는데 매우 유용한 도구이다. 특히 200kV의 가속전압 투과전자현미경에 FEG(Field Emission Gun) 전자총이 장착되기 시작하면서 TEM은 비정질 구조 연구에 하나의 핵심적인 도구로서의 역할이 크게 기대되는 장비가 되었다. 본 연구에서는 TEM의 microanalysis accessary인 EELS(Electron Energy Loss Spectroscopy)technique을 주로 이용하던 기존의 방법대신 고 분해능(HRTEM(High Resolution Transmission Electron Microscopy)의 image로부터 비정질 정량묘사의 유일한 도구인 원자분포함수(RDF(Radial Distribution Function))로의 Reconstruction을 Simulation을 이용하여 시도하였다. 비정질 HRTEM image의 정량분석을 통하여 이 분야에서의 TEM의 한계를 이해하기 위하여 몇 모델을 제시하고 사용하였다. 또한 비정질 구조를 정량적으로 묘사하는 도구인 원자분포함수를 알아보고 비정질재료를 보다 물리적으로 모델링하기 위하여 가능한 모델 제시 후 첫 단계로서 HRTEM image에서 원자분포함수를 이끌어내기 위한 모델링을 수행하고 비정질 게르마늄(a-Ge) film에 대하여 실제로 적용하여 보았다. 마지막으로 실험적인 접근으로 200kV FE-TEm (poingt resolution 0.14nm) 으로 비정질 Ge의 image를 solw Scan CCD를 이용한 Elastic image를 Through Focus로 얻었으며 수치적인 정량비교를 역격자 공간에서 출발한 가장 물리적인 구조 모델을 이용하여 수행하였다. 모든 정량비교는 image의 Fourier 변환인 Diffractogram으로 하였다. 결론적으로, 많은 복잡한 수치 처리과정을 거쳐야 하지만 HRTEM의 image로부터 구조에 대한 정보(RDF)는 명확하게 얻을 수 있었다.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.100-106
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• 2001

The size distributions of electrospray droplets from the Taylor cone in cone-jet mode are directly measured by using a freezing method and a transmission electron microscope (TEM) image processing technique. These results are compared with the data obtained by an aerodynamic size spectrometer (TSI Aerosizer DSP). The use of glycerol seeded with NaI and a freezing method make it possible to sample droplets with their original sizes preserved. Since pictures of droplets are taken with TEM with very low vapor pressure of the solution, evaporation is suppressed by freezing. For liquid flow rates below 1 nl/sec, the measured droplet diameters by the TEM image processing technique and the aerosizer are in the range of 0.25 to $0.32{\mu}m$ and 0.30 to $0.40{\mu}m$, respectively. Comparing the TEM data with the aerosizer measurements, it has been revealed that the TEM image processing technique can afford more accurate values of droplet size distributions in the submicron range of 0.1 to $0.4{\mu}m$.

• Applied Microscopy
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• v.41 no.3
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• pp.215-222
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• 2011

We discuss the experimental procedure for extracting reliable phase information from a defocus series of transmission electron microscopy (TEM) dark-field images using the transport of intensity equation (TIE). Taking InGaN/GaN multi-quantum well light-emitting diode as a model system, various factors affecting the final result of reconstructed phase such as TEM sample preparation, TEM imaging condition, image alignment, the correction of defocus values and the use of high frequency pass filter are evaluated. The obtained phase of wave function was converted to the geometric phase of the corresponding lattice planes, which was then used for the two-dimensional mapping of lattice strain following the dark-field inline holography (DIH) routine. The strain map obtained by DIH after optimized image processing is compared with that obtained by the geometric phase analysis of high resolution TEM (HRTEM) image, manifesting that DIH yields more accurate and reliable strain information than HRTEM-based GPA.

• Journal of Powder Materials
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• v.24 no.4
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• pp.285-291
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• 2017

We propose a custom analysis technique for the dark field (DF) image based on transmission electron microscopy (TEM). The custom analysis technique is developed based on the $DigitalMicrograph^{(R)}$ (DM) script language embedded in the Gatan digital microscopy software, which is used as the operational software for most TEM instruments. The developed software automatically scans an electron beam across a TEM sample and records a series of electron diffraction patterns. The recorded electron diffraction patterns provide DF and ADF images based on digital image processing. An experimental electron diffraction pattern is recorded from a IrMn polycrystal consisting of fine nanograins in order to test the proposed software. We demonstrate that the developed image processing technique well resolves nanograins of ~ 5 nm in diameter.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.10
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• pp.1400-1407
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• 2001

The size distributions of electrospray droplets from the Taylor cone in cone-jet mode are directly measured by using a freezing method and a transmission electron microscope (TEM) image processing technique. These results are compared with the data obtained by an aerodynamic size spectrometer (TSI Aerosizer DSP). The use of glycerol seeded with NaI and a freezing method make it possible to sample droplets with their original sizes preserved. Since pictures of droplets are taken with TEM with very low vapor pressure of the solution, evaporation is suppressed by freezing. For liquid flow rates below 1 nl/sec, the measured droplet diameters by the TEM image processing technique and the aerosizer are in the range of 0.25 to 0.32 m add 0.3B to 0.40m, respectively. Comparing the TEM data with the aerosizer measurements, it has been revealed that the TEM image processing technique can afford more accurate values of droplet size distributions in the submicron range of 0.1 to 0.4m.

• Applied Microscopy
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• v.35 no.3
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• pp.105-112
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• 2005

In this review, the important ideas of coherence theory are introduced. The transfer function and damping envelopes of the microscope due to temporal and spatial coherence are described. The passbands and the condition of Scherzer focus are also disscussed in associated with the resolution of transmission electron microscope.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.207-208
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• 2007

In this paper, the tilted image sequence, which is obtained the transmission electron microscopy (TEM) for a 3D reconstruction, is aligned based on the fiducial marker method. A direct correlation method is also conducted between adjacent tilted images for the performance comparison. Using real TEM tilted images, we can successfully perform the alignment.

• Journal of the Mineralogical Society of Korea
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• v.8 no.1
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• pp.1-12
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• 1995

옥천 변성대 남서부 지역에서 산출되는 변성 니질암에서는 muscovite, biotite 및 chlorite를 주로하는 phyllosilicate가 서로 intergrowth 또는 interlayer를 이루는 것이 편광현미경 관찰, EPMA 분석, Back Scattered Electron (BSE) image 관찰 및 Transmission Electron Micro-scope(TEM) 관찰을 통하여 확인되었다. 이들 광물들은 편광현미경 관찰에서 흔히 각각의 입자를 식별할 수 없을 정도의 미세 규모로 서로 intergrow 되어 있으며BSE image에서는 0.1$\mu\textrm{m}$ 이하의 아주 작은 크기에서부터 10.0$\mu\textrm{m}$ 정도 크기까지 다양한 규모의 intergrow를 형성하고 있음이 관찰되었다. TEM scale에서는 개별 layer 크기(약 10$\AA$)에서부터 수십 개 layer 크기의 interlayering을 보여준다. 이와 같은 intergrowth 또는 interlayering의 결과로 EPMA 분석에서 종종 보기에는 규진(homogeneous)한 입자라 하더라도 두 개 이상의 광물 성분이 섞여 있는 분석값을 나타내며 이러한 nonstoichiometry는 BSE image에서 interlayer(또는 intergrow) 된 것으로 관찰되는 부분에서 더욱 두드러진다.Chlorite zone에서는 chlorite와 muscovite의 interlayering (C/M)이 주로 발견되며 biotite zone과 garnet zone에서는 chlorite와 biotite의 interlayer (C/B)가 주로 관찰된다. 이는 chlorite zone에서는 속성작용에서 보편적으로 나타나는 C/M으로부터 chlorite가 분리되는 광물반응이 일어나는데 반해서 biotite zone과 garnet zone에서는 chlorite로부터 C/B를 거쳐 biotite를 생성하는 광물반응이 일어나는 것을 의미한다. 이와 같은 현상은 변성작용에서 phollosilicate의 광물반응의 엄밀한 의미에서는 평형(equilibrium) 상태에서 균질한 광물을 생성하기보다는 비평형(disequilibrium) 반응으로 일어난다는 것을 의미한다.

• 한국전자현미경학회:학술대회논문집
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• 2003.05a
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• pp.23-24
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• 2003

• Applied Microscopy
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• v.37 no.3
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• pp.199-208
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• 2007

We have made an optical device to study the wave optics phenomena, such as image and diffraction pattern, constructive and destructive interference, by direct operation of laser beam and optical lenses. It consists of laser beam, goniometer, objective lens, intermediate lens, projection lens, CCD system, and computing system. As a result of the performance test, we were able to magnify samples up to 44 times with the resolution of about $5{\mu}m$. It is expected to help EM users understanding more easily principles of transmission electron microscopy (TEM).