• 비파괴검사학회지
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• 제30권1호
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• pp.46-53
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• 2010

항공기용 복합재료 내부 여러 층에서 발생하는 박리를 정량적으로 평가하기 위한 X-ray 후방산란 검사장치를 개발하였다. 복합재료 두께방향으로의 역산란 밀도변화로부터 층간 박리를 검사하는 슬릿 방식의 카메라와 컴퓨터로 제어되는 X-ray 선원, 그리고 센서로 구성되는 X-ray 후방산란장치를 제작하여 그 성능을 충격하중에 의해 만들어진 인공결함시편을 이용해 검증하였다. 결함평가를 위해 복합재료내 산란장의 크기를 이론적으로 계산하는 수학적 해석 모델을 볼츠만 방정식을 이용하여 제안하였으며 적응필터 알고리즘을 사용하여 산란 노이즈를 최소화 하였다. 다중 박리 결함을 X-ray 후방산란장치를 통해 효과적으로 검출하였으며, 박리 위치와 박리 상태를 모두 정확하게 검사할 수 있음을 실험을 통해 확인하였다.

• 비파괴검사학회지
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• 제20권6호
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• pp.545-554
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• 2000

충격에 의해 복합 재료 내에 발생하는 층간 박리를 정량적으로 평가하기 위한 비파괴 방법중에서 Compton X-ray 역산란 기술은 초음파에 비해 비접촉식이며 박리 층간의 상호간섭이 없어 복합재료 판면의 박리 층의 위치와 크기를 검사하는데 효과적인 방법으로 사용되어 왔다. 그러나 X-ray역산란 기술에 있어서 복합재료의 박리 층과 같은 미세한 결함의 측정을 위해 측정 정도를 높이면 역산란 양의 감소로 인해 신호 대 잡음 비(SNR)가 급격히 감소하여 결함검출 가능성이 크게 저하된다. 본 논문에서는 복합재료의 특성을 고려한 X-ray 역산란 모델을 기초로 적응필터를 사용하여 결함신호를 비선형 감쇄, 빔 경화(X-ray hardening), 비균질 특성과 같은 잡음 신호로부터 분리, 추출하는 방법을 제시하였다. 이렇게 분리된 결함신호로부터 정량적인 결함(박리)의 위치와 크기를 수학적 산란 모델과의 비교를 통해 최소 자승법을 이용하여 결정하였다.

• 한국전기전자재료학회논문지
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• 제24권8호
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• pp.647-653
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• 2011

In this study, a method to measure the thickness of thin film by EDS (energy dispersive spectroscopy) is suggested. We have developed a model which calculates the thickness of thin film from the characteristic x-ray intensity ratio of the elements in thin film and substrate by considering incident electron beam energy, x-ray generation curve, backscattering and absorption of x-ray, take-off angle of x-ray and tilt angle of the sample. We obtained the relation curve between the film thickness measured experimentally and the x-ray intensity ratio of elements. The film thicknesses calculated from the model agrees quite well with those measured experimentally. Therefore, the thin film thickness can be measured rapidly and accurately by using the model developed in this study and the x-ray intensity ratio obtained in EDS analysis.

• 분석과학
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• 제7권3호
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• pp.301-313
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• 1994

X-선 광전자분광법(XPS)과 라더포드 후방산란법(RBS)은 첨가제 분석, 화학구조 규명은 물론 시료 표면 원소의 정성 및 정량, 결합에너지 준위, 수직분포 분석을 통한 동일성 판정 등에 응용할 수 있다. $XeF_2$와 C-F plasma로 표면을 처리한 polyethylene, acrylonitrile butadien rubber, polypropylene, glass, fiber 및 paper를 XPS와 RBS로 분석한 결과 불소원자가 시료의 표면에 침투한 것을 확인할 수 있었으며, 표면 원소의 분포가 미처리된 시료의 표면원소 분포와 차이가 있었다.

• 한국진공학회지
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• 제6권S1호
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• pp.1-15
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• 1997

Titanium oxide films were prepared by ion beam enhanced deposition where the films were synthesized by deposition titianium atoms and simultaneously bombarding with xenon ion beam at an energy of 40 keV in an $O_2$ environ,ent. Structure and composition of titanium oxide films were investigated by X-ray Doffractopm (XRD) Ritjerfprd Backscattering Spectroscopy (RBS) and X-ray Diffraction(XRD) Rutherford Backscattering Spectroscopy (RBS) and X-ray photoelectron spectroscopy (XPS) The results show that thestructure of the prepared films exhibit a rutile phase structure wit high(200) orientation and the O/Ti ratio of the titanium oxide films was about 2:1 XPS anlysis shows that $Ti^{2+},Ti^{3+}\;and\;Ti^{4+}$ chemical states exist on the titanium oxide films. the blood compatibility of the titanium oxide films was studied by measurements of blood clotting time and platelet adhesion. The results show that the anticoagulation property of titanium oxide films improved significantly and better than that of LTI-carbon which was widely used to fabricate artificial heart valve.

• 한국재료학회지
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• 제9권9호
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• pp.878-882
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• 1999

분자선증착법으로 (0001) 사파이어 기판 위에 $Al_xGa_1-_xN$ 에피층을 AlN 몰비를 변화시키면서 성장시켰다. AlN 몰비는 0.16에서 0.76까지 변화시켰으며 X선의 회절 실험과 Rutherford backscattering spectroscopy 방법을 이용하여 AlN 몰비를 결정하였다. $Al_xGa_1-_xN$ 에피층의 깊이 방향의 조성 변화를 관찰하였으며 스퍼터 시간에 대해 각 원소가 일정한 원자 농도를 가짐을 알 수 있었다. AlN 몰비의 증가에 따른 표면 특성의 변화를 관찰하기 위하여 atomic force microscopy 측정을 수행하였다. 표면에서의 입자 모양이 AlN 몰비가 변화함에 따라 원형에서 침상형태로 변화함을 알 수 있었다. 표면 입자에 대한 root mean square 값과 average roughness 값을 구하였으며 AlN 몰비를 바꿈에 따라 나타나는 변화를 관찰하였다.

• 비파괴검사학회지
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• 제26권6호
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• pp.417-426
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• 2006

A Digital X-ray imaging system using Compton backscattering has been developed to obtain a cross-sectional profile and mass loss of corroded lap-splices of aging aircraft from density variation. A slit-type camera was designed to focus on a small scattering volume inside the material, from which the backscattered photons are collected by a collimated scintillator detector for interpretation of material characteristics. The cross section of the lap-joint is scanned by moving the scattering volume through the thickness direction of the specimen. The mass loss of each layer has been estimated from a Compton backscatter A-scan to obtain the thickness of each layer including the aluminum sheet, the corrosion layer and the sealant. Quantitative information such as location and width of planar corrosion in the lap splices of fuselages is obtained by deconvolution using a nonlinear least-square error minimization method(BFGS method): A simple reconstruction model is also introduced to overcome distortion of the Compton backscatter data due to attenuation effects attributed to beam hardening and quantum noise.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.206.2-206.2
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• 2014

Recently, particle induced X-ray emission (PIXE) analysis system was installed at the 2MV ion acceleration system in Korea institute science and technology (KIST). This installation is for complement to low atomic resolution of heavy atoms at Rutherford backscattering spectrometry (RBS) system. For quantitative analysis, a mass calibration of the PIXE set-up has been done with thin film standards and. The GUPIX software package has been used to process the PIXE spectra and the results are compared with the values from RBS system. Therefore, the instrumental constant H (solid angle and correction factor) is determined relying completely on the GUPIX data base (cross-sections, fluorescence and Coster-Kronig probabilities, stopping powers and attenuation coefficients) for a large set of elements. These H values can be used in future analysis.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2003년도 연료전지심포지움 2003논문집
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• pp.83-88
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• 2003

PtRu alloy and $PtRu-WO_3$ nanocomposite thin-film electrodes for methanol electrooxidation were fabricated by means of a sputtering method. The structural and electrochemical properties of well-defined PtRu alloy thin-film electrodes were characterized using X-ray diffraction, Rutherford backscattering spectroscopy. X-ray photoelectron spectroscopy, and electrochemical measurements. The alloy thin-film electrodes were classified as follows: Pt-based and Ru-based alloy structure. Based on structural and electrochemical understanding of the PtRu alloy thin-film electrodes, the well-controlled physical and (electro)chemical properties of $PtRu-WO_3$, showed superior specific current to that of a nanosized PtRu alloy catalyst, The homogeneous dispersion of alloy catalyst and well-formed nanophase structure would lead to an excellent catalytic electrode reaction for high-performance fuel cells. In addition, the enhanced catalytic activity in nanocomposite electrode was found to be closely related to proton transfer in tungsten oxide using in-situ electrochemical transmittance measurement.

• 한국표면공학회지
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• 제29권5호
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• pp.467-473
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• 1996

Heteroepitaxial growth of cubic silicon carbide films on Si(001) and Si(111) substrates at temperatures 900-$1000^{\circ}C$ has been achieved by high vacuum chemical vapor deposition using the single precursor 1, 3-disilabutane without carrying out the carbonization process of the substrate surfaces. The deposition temperature range is much lowered compared with conventiontional chemical vapor deposition where separate sources for silicon and carbon are employed. The deposition procedure is quite simple and safe. The qualities of the films were found to be very good judging from the results obtained by various characterization techniques including reflection high energy electron diffraction, X-ray diffraction, X-ray pole figure analysis, Rutherford backscattering spectrometry, Auger depth profiling, and transmission electron diffraction.