• Korean Journal of Crystallography
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• v.7 no.1
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• pp.20-29
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• 1996

Sr0.6Ca0.4CuO2 single crystal has been synthesized by flux method and characterized by the single crystal X-ray diffraction. The compound has the orthorhombic system and the space group is Cmcm(63), lattice parameters are a=3.4645Å, b=16.1417Å, c=3.8727Å. In the (Sr1-xCax)CuO2 compound the limit of Ca from substitution for Sr was determined by the change of bond length. For this, X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDAX) and electron probe micro-analysis (EPMA) were used. From the change of Cu-O bond length as the Ca substitution, we concluded the limit of Ca incorporation Xca≒0.73.

• Journal of the Korean Ceramic Society
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• v.45 no.3
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• pp.146-149
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• 2008

Strontium-substituted $Sr_{1-x}Ba_xAl_2O_4:Eu^{2+},\;Dy^{3+}$ compositions were prepared by the solid state synthesis method. These compositions were characterized for their phase, crystallinity and morphology using powder x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Photoluminescence properties were investigated by measuring excitation spectra, emission spectra and decay time for varying Ba/Sr concentrations. Photoluminescence results show higher luminescence and long decay time for $Sr_{1-x}Ba_xAl_2O_4:Eu^{2+},\;Dy^{3+}$(x=0). This is probably due to the influence of the 5d electron states of $Eu^{2+}$ in the crystal field. Long persistence was observed for these compositions due to $Dy^{3+}$ co-doping.

• Journal of the Mineralogical Society of Korea
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• v.26 no.1
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• pp.27-34
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• 2013

X-ray powder diffraction is one of the most powerful techniques for qualitative and quantitative analysis of crystalline compounds. Thus, there exist a number of different methods for quantifying mineral mixtures using X-ray diffraction pattern. We present here the use of Rietveld and PONKCS (partial or no known crystal structure) methods for quantification of amorphous and crystallized mineral phases in synthetic mixtures of standard minerals (amorphous silica, quartz, mullite and corundum). Pawley phase model of amorphous silica was successfully built from the pattern of 100 wt% amorphous silica and internal standard-spiked samples by PONKCS approach. The average of absolute bias for quantities of amorphous silica was 1.85 wt%. The larger bias observed for lower quantities of amorphous silica is probably explained by low intensities of diffraction pattern. Averages of absolute bias for minerals were 0.53 wt% for quartz, 0.87 wt% for mullite and 0.57 wt% for corundum, respectively. The PONKCS approach achieved improved quantitative results compared with classical Rietveld method by using an internal standard.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.5
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• pp.218-223
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• 2001

The chemical-mechanical polishing process was carried out for 2"-dia. sapphire wafer grown by horizontalBridgman method on the urethane lapping pad with the silica sol. The polished wafer shows the full-width at halfmaximum of 200~400 arcsec in double-crystal X-ray diffraction, indicating that the slicing, grinding and lapping processes before the polishing process affected the crystalline structural property of the wafer surface by the mechanical residual stress. For the inclusion of surface treatments after chemical-mechanical polishing such as the thermal annealing at the temperature of $1,200^{\circ}C$for 4 hrs. and chemical etching, the crystalline quality was sigdicantly enhanced with the reduced full-width at half maximum up to 8.3 arcsec.arcsec.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.325-330
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• 2009

High pressure x-ray diffraction study was performed on a synthetic FeOOH-goethite to check out its compressibility at room temperature. Angular dispersive x-ray diffraction method was employed using a symmetrical diamond anvil cell with synchrotron radiation. Bulk modulus was determined to be 222.8 GPa under assumption of $K_{T'}$ of 4.0. This value is too high comparing with the previously published values from natural samples. It has been discussed the possible causes to incur its high bulk modulus value according to the production conditions.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.2
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• pp.78-86
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• 2002

In general, X-ray diffraction method detects the changes of crystal lattice under material surface using the angle of diffraction 2$\theta$. This technique which deals with in the presented paper can be applied to a behavior on the slipped band or the micro crack cause to material degradation. The relation between half-value breadth and cycle numbers shows three stages, which consist of rapid decrease in the initial cycle, slight decrease in the middle cycle, and then rapid decrease in the final cycle. The ratio of half-value breadth has a constant value on B/B$\_$0/ - N diagram under the loading condition except early part of fatigue life. The ratio of half-value breadth B/B$\_$0/ - log N$\_$f/ with respect to number of cycle to failure N$\_$f/ has linear behavior on B/B$\_$0/ - log N$\_$f/ diagram. Therefore, the evaluation of fatigue life by the average gradient has much less mean error than the estimation of fatigue life by log B/B$\_$0/ - log N/N$\_$f/ relation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.7
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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.

• Proceedings of the Materials Research Society of Korea Conference
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• 2002.11a
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• pp.164-164
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• 2002

• Journal of Ceramic Processing Research
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• v.13 no.spc2
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• pp.403-406
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• 2012

Effect of thickness on ZnO properties including the compositional ratio and crystallinity has been systematically investigated using a variety of characterization tools of x-ray diffraction, field emission scanning electron microscopy, x-ray fluorescence and x-ray photoelectron spectroscopy. Interestingly, it was observed that ZnO films below 80 nm in thickness were in oxygen deficiency, while the oxygen ratio was increased in the films above the thickness, although the compositional ratio of ZnO film was not linearly varied with increasing film thickness. Also, ZnO crystallinity, which is characterized by (002) diffraction pattern, was clearly improved with increasing film thickness. The properties of ZnO film with different sputtering time and the nature of direct current reactive sputtering process were discussed in terms of compositional ratio, especially oxygen ratio in ZnO film.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.61-66
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• 2008

This study is performed to compare characteristics of various measurement technique for weld residual stress. AISI 304 plate with one path weld on the surface was manufactured for this study. Hole drilling method, X-ray diffraction method and instrumented indentation method were used to measure the residual stress before and after welding. All the results were compared and analyzed.