• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.176-177
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• 2014

The new algorithm was proposed to quantify symmetry recorded in convergent beam electron diffraction (CBED) patterns and symmetry mapping. The proposed algorithm is based on the normalized cross-correlation coefficient (${\gamma}$) for quantifying the amount of symmetry in a CBED pattern. The quantification and mapping procedures are automatically controlled by the script implemented in Gatan Digital Micrograph$^{(c)}$. We apply the quantitative CBED measurement to a strained Si sample to test the sensitivity to defects.

• The Korean Journal of Ceramics
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• 제6권3호
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• pp.236-239
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• 2000

Both the X-ray diffraction data of the normal direction in the sample orientation and the pole figure data of three reflections, (111), (200) and (220), were used to do the Rietveld refinement for the copper sheet prepared by a cold rolling process. The agreement between calculated and observed patterns was not satisfactory, which was attributed to the preferred orientation effect of the copper sheet. The Rietveld refinement for the copper sheet could be done successfully by applying the pole density of each reflection obtained from the corresponding inverse pole figure to the X-ray diffraction data of the normal direction. The R-weighted pattern, $R_{wp}$ was 12.99% and the goodness-of-fit indicator, S, was 3.68.

• Bulletin of the Korean Chemical Society
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• 제8권1호
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• pp.6-9
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• 1987

The study of the $Na_3YSi_3O_9$ structure, by x-ray diffraction and infrared spectrum, showed that $Na_3YSi_3O_9$ is similar to $Na_4CaSi_3O_9$ except for its being pseudo-cubic instead of cubic. The peaks in the x-ray diffraction pattern of $Na_3YSi_3O_9$ could therefore be indexed on the basis of the $Na_4CaSi_3O_9$ cell. Also, modified $Na_3MSi_3O_9$ (M = Lu, Yb, Tm, Er, Y, Ho, Dy, Gd, Eu, and Sm) type compounds were synthesized by introducing excess sodium, decreasing M(III) concentration, and substituting small amount of phosphorus for silicon. The unit cell parameters of the composition $Na_{3.2}M_{0.7}Si_{2.9}P_{0.1}O_{8.7}$ were estimated from x-ray powder diffraction patterns using the Cohen method.

• 한국전기전자재료학회논문지
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• 제15권10호
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• pp.896-901
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• 2002

The polarization and strain behavior of multilayer ceramic actuators fabricated by tape casting using a PNN-PZT ceramics were investigated in association with electrode size and internal layer number. Spontaneous polarization and strain decreased with increasing electrode size. In addition, the increase of internal layer number brought reduced spontaneous polarization and increased the field-induced strain. Because the actuators structure is designed to stack ceramic layer and electrode layer alternatively, the ceramic-electrode interfaces may act as a resistance to motion of domain wall. To analyze the effect of ceramic-electrode interface, the diffraction intensity ratio of (002) to (200) planes was calculated from X-ray diffraction patterns of samples subjected to a voltage of 200 V. The diffraction intensity ratio of (002) to (200) planes was decreased with increasing electrode size and internal layer number. The diffraction intensity ratio and straining behavior analyses indicate that the Polarization and strain were affected by the amount of 90°domain decreasing with increasing electrode size and internal layer number. Consequently, the change of polarization and displacement with respect to electrode size and layer number is likely to be caused by readiness of the domain wall movement around the interface.

• 대한전자공학회논문지
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• 제26권5호
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• pp.23-31
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• 1989

임의의 각을 갖는 쇄기형 유전체의 양 경계면에 E-편파된 입사시 전자파의 회절문제에서 쇄기형 유전체의 모서리 근방에서 정전기적 극한의 모서히 조건을 만족하는 해를 구하였다. 물리광학근사로 구한 회절계수를 유전체 경계면을 따라 분포한 Neumann 전개된 면전류로 교정하였다. 모서리 끝점에 분포한 다극선전원으로 교정된 회절계수에 비하여, 본 논문에서 구한 회절계수는 유전체 내부의 비유전율을 점차 크게 할 경우 좀 더 정확히 쇄기형 완전도체의 회절함수에 접근함을 보았다.

• 대한기계학회논문집A
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• 제33권8호
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• pp.793-798
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• 2009

In this paper, the simulation and optimization of SRH (Surface Relief Hologram) masks for printing LCD gate patterns using TIR (Total Internal Reflection) holographic lithography was investigated. A simulation and optimization algorithm based on SDTA (Scalar Diffraction Theory Analysis) method was developed. The accuracy of the algorithm was compared to that of the RCWA (Rigorous Coupled Wave Analysis) method for estimating the Fresnel diffraction pattern of Cr amplitude masks for the given system geometry. In addition, the results from the optimization algorithm were validated experimentally. It was found that one to the most important conditions for the fabrication of SRH masks is to avoid nonlinear shape distortions of the resulting grating. These distortions can be avoided by designing SRH masks with recorded gratings having small aspect ratios of width versus depth. The optimum gap size between the Cr and SRH masks was found using the optimization algorithm. A printed LCD gate pattern with a minimum line width of $1.5{\mu}m$ exposed using the optimized SRH mask was experimentally demonstrated.

• 한국전기전자재료학회논문지
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• 제17권9호
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• pp.994-1000
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• 2004

We studied the characteristics of annular phase gratings as spatial frequency filters. We first calculated the Fraunhofer diffraction patterns of annular gratings and then got the modulation transfer function (MTF) from the zeroth order Hankel transform of the intensity distribution function. Binaryphase annular grating shows higher diffraction efficiency than binary phase rectangular grating. But the MTF decreases linearly in the low-frequency region as that of rectangular grating does. The diffraction pattern of 4-phase annular grating is similar to that of 2-phase grating and hence MTFs of the two are much alike. For 8-phase annular grating, the 7th order diffracted beam is the lowest one next to the first. Consequently, the diffraction efficiency is very high and the MTF graph is curved upward. The diffracted beams except the first order are negligible and hence the MTF characteristics are more improved in the case of 16-phase grating. But the degree of improvement becomes lowered c(Impaled with 8-phase grating. We made a 16-phase annular grating and measured its MTF. The experimental result agrees well with the calculated one.

• 분석과학
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• 제26권5호
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• pp.340-351
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• 2013

The chemical element and structural characterization of different types of cements and its brick stones are been investigated under forensic aspects using X-ray florescence (XRF) and X-ray diffraction (XRD) spectrometer. The XRF provides rapid compositional data for controlling almost all stages of raw materials, clinker and cement. The decisive advantage of XRD methods is based on the unique character of the diffraction patterns of crystalline substances, the ability to distinguish between elements and their oxides, and the possibility to identify chemical compounds, polymeric forms, and mixed crystals by non-destructive examination. Therefore, combination of these examinations is useful and able to apply for the forensic analysis in comparison of cements and brick stones. There are more study remained to determine the viability of method for forensic analysis of brick stones and the limits of the discrimination that can be achieved.

• 한국기계가공학회지
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• 제13권4호
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• pp.7-12
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• 2014

A transparent poly methyl methacrylate (PMMA) optical micro-pyramid array-pattern is designed and fabricated using an injection modeling technique. The device's optical characteristics are tested and analyzed theoretically. In the optical pattern generated using the fabricated PMMA pattern, the components, due to not only refraction but also diffraction, are observed simultaneously. Wave optic modeling and analysis reveals that the energy ratio between the diffraction and refraction in the optical pattern are dependent on the critical dimension of the optical pattern such that the refraction and diffraction tend to be directly and inversely proportional to the pattern dimension, respectively.

• 한국전기전자재료학회논문지
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• 제23권7호
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• pp.517-520
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• 2010

Lead-free $0.9(Na_{0.52}K_{0.48})NbO_3$ - $0.1LiTaO_3$ piezoelectric ceramics doped with $Ag_2O$ (0-4 mol%) have been prepared by the conventional mixed oxide method. The structural and electrical properties were analyzed in order to find its potential applications. The crystal structure of 1-4 mol% Ag doped $0.9(Na_{0.52}K_{0.48})NbO_3$-$0.1LiTaO_3$ lead free piezoelectric ceramics were investigated for several sintering temperatures ($1100^{\circ}C$) by the use of X-ray diffraction analysis. In order to analyze the effect of Ag dopants on the $0.9(Na_{0.52}K_{0.48})NbO_3$-$0.1LiTaO_3$ ceramic, the diffraction intensity ratio of the (002) to (200) planes were calculated from the X-ray diffraction patterns of the ceramic samples.