• Journal of Applied Biological Chemistry
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• v.58 no.4
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• pp.345-348
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• 2015

Dried Rehmannia Radix Preparat, produced in different geographic origins of Korea and China, were investigated for the trace element contents using X-ray fluorescence spectrometry. When the estimated data for 35 kind of elements including K, P, S, Cl, Si, Al, Fe, Sn, etc on 143 samples were analyzed by canonical discrimination technique, the average classification correct rate was 92.3% and the significance was less than 0.0001. In case of reducing the number of elements for statistic analysis from 35 to 8 and to 3, the correct rates were also reduced to 88.1% and to 84.6%. The correct rate for Chinese samples ranged from 94.6-96.0%, while those for Korean ranged from 72.5-89.9%.

• Analytical Science and Technology
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• v.22 no.5
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• pp.422-431
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• 2009

The analytical results of wear metals such as Na, Mg, Al, Si, P, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, Ba, Pb in oil samples are compared by portable and bench-top XRF methods as a basic study for the development of portable X-ray fluorescence spectrometer. The instrumental parameters such as measurement time of portable and bench-top XRF were optimized using certified reference materials of hydrocarbon oil with 20 wear metals in concentration range from 10 to 900 mg/kg. The analytical results of 20 wear metals in certified reference materials and new/used engine oil samples were compared by empirical and fundamental parameter methods.

• Korean Journal of Food Science and Technology
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• v.44 no.4
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• pp.484-487
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• 2012

A discrimination technique for domestic and imported Scutellaria baicalensis was developed using an energy dispersive X-ray fluorescence spectrometer (ED-XRF). Mineral content ratios, of a total of 43 species, including P, S, Cl, K, Ca, Mn, Fe, Cu, and Zn, were measured among 204 samples. Macro element content ratios and trace element content ratios were determined using the standardless fundamental parameters (SLFP) analysis. Inorganic element ratios of P, S, K, Ca, Cl, Mn, and Fe were significantly different between domestic and imported samples. The result from the canonical discriminant analysis showed that the accuracy of geographical origin discrimination was 95.15%; the correlation coefficient was 0.888. It was concluded that this technique could be used as a useful method in discriminating the geographical origins between domestic and imported Scutellaria baicalensis.

• New Physics: Sae Mulli
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• v.68 no.12
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• pp.1308-1314
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• 2018

$Er^{3+}$ and $Yb^{3+}$ co-doped $Y_3Ga_5O_{12}$ polycrystalline powders were prepared by using a solid-state reaction method, and their crystallinities were measured using X-ray diffraction. According to the results of X-ray diffraction, the powders showed a polycrystalline tetragonal structure. The photoluminescence and the upconversion luminescence properties of the $(Y_{0.85-x}Yb_{0.15})_3Ga_5O_{12}:Er^{3+}_x$ (x = 0.03, 0.06, 0.09, 0.12 and 0.15) phosphors were investigated in detail. Green and red upconversion emissions were observed for the phosphors excited by 980 nm radiation from a semiconductor laser. The powders exhibited strong green and weak red upconversion emission peaks at 553 and 660 nm, respectively. Also, their upconversion processes were explained using an energy-diagram analysis and the strongest upconversion intensity was emitted by the powder with a 0.12 mol $Er^{3+}$ ion concentration.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.403-405
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• 2008

Solid state lighting 용 적색 형광체로 적용하기 위하여 $BaTiO_3$:$Pr^{3+}$:$Ga^{3+}$를 다음과 같이 합성하였다. 출발 물질로 $BaCO_3$,$Pr(NO_3)_3$ $6H_2O$, $TiO_2$, $Ga_2O_3$을 사용 하였으며, $BaTiO_3$:$Pr^{3+}\;_x$(x=$0.001{\sim}0.2$):$Ga^{3+}\;_y$(y=0.05, 0.1, 0.5 1, 2, 3)를 각각의 조성대로 혼합한 후 $600^{\circ}C$에서 10시간 전처리 하였다. 전처리한 시료를 시편으로 제조하여 $1200^{\circ}C$ 공기중에 4시간 소성하여 최종물질인 $BaTiO_3$:$Pr^{3+}\;_x$:$Ga^{3+}\;_y$을 얻었다. 이 화합물을 X-선 회절 분석 결과 공간군 P4MM을 갖는 페로브스카이트임을 알 수 있었다. 이 화합물을 적색형광체로 적용하기 위해 PL과 PLE측정을 통하여 형광특성을 알아본 결과 618nm에서 x=0.011, y=1.0 일 때 특성이 가장 우수한 것으로 나타났다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.352-356
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• 2011

주로 탄화수소화합물로 구성된 EPS(Expended poly styrene)는 뛰어난 단열성능, 경제성, 건식공법의 시공편리성으로 단열재로 많이 사용되지만 화재에 취약한 단점이 있다. 최근 EPS패널의 다양한 난연화를 통해 난연EPS패널제품이 개발되고 있고 시장에서의 사용이 증가되고 있다. 그러나 가짜 난연EPS제품의 사용이 사회적 문제가 되고 있는 것도 현실이다. 본 연구에서는 난연EPS와 일반EPS가 성분이 다른점을 이용하여, 현장에서 시공되고 있는 시료의 진위여부 판단을 위해 X-선형광분석기(XRF)를 사용한 원소분석을 시도하였다. 분석결과 매우 간단한 방법으로 시료의 진위여부를 확인할 수 있었으며, 따라서 현장에서 사용될 수 있는 분석법으로 적용가능성에 대하여 고찰하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.238-244
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• 2013

In energy dispersive X-ray fluorescence analysis, the removal of the continuum on which the X-ray spectrum is superimposed is one of the most important processes, since it has a strong influence on the analysis result. The existing methods which have been used for it usually require tight constraints or prior information on the continuum. In this paper, an efficient background correction method is proposed for Energy Dispersive X-ray fluorescence (EDXRF) spectra. The proposed method has two steps of background modeling and background correction. It is based on the basic concept which differentiates background areas from the peak areas in a spectrum and the SNIP algorithm, one of the popular methods for background removal, is used to enhance the performance. After detecting some points which belong to the background from a spectrum, its background is modeled by a curve fitting method based on them. And then the obtained background model is subtracted from the raw spectrum. The method has been shown to give better results than some of traditional methods, while working under relatively weak constraints or prior information.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.167-167
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• 2000

전지 재료의 충방전 과정 연구에는 X-선 분말회절(x-ray powder diffraction techniques)과 중성자회절을 많이 사용하였다. 하지만 이러한 분석기술은 long-range order의 구조에 관한 정보를 제공하는데 유용하지만 atomic scale의 구조에 관한 정보를 얻기에는 한계가 있다. Li 전지에서의 전기화학적 반응에서는 cathode 물질에 포함된 전이금속의 산화, 환원 반응에 의한 Li 이온의 intercalation (charge process)과 deintercalation (discharge process) 현상이 일어난다. 이러한 충방전 과정은 알려지지 않은 다양한 형태의 위상 변화를 동반하게 되는데 x-선 이나 중성자를 이용한 powder diffraction techniques 로는 단지 정성적인 결정학적 정보를 얻을 수 있다. 따라서 최근에 원자 단위의 local structure에 관한 정보와 electrochemical state에 관한 정보를 동시에 얻을 수 있는 X-ray Absorption Fine Structure (XAFS) 분석기술을 Li 전지분석에 활용하기 시작하였다. XAFS는 하나의 x-ray 흡수원자에 대해서 주변원자들의 원자구조에 관한 정보와 구성 원소의 electrochemical state에 관한 정보를 얻을 수 있는 분석방법이다. X-ray Induced Electron Emission Spectroscopy (XIEES)는 x-ray에 의해서 방출된 전자를 검출하여 스펙트럼을 얻는 기능을 함축적으로 나타낸 것으로, x-ray를 물질 표면에 조사하여 발생하는 광전자, Auger 전자, 이차전자 등을 전자검출기(Channel Electron Multiplier: CEM)로 검출하는 기능과, 시료를 투과한 x-ray와 시료에서 발생하는 형광 x-ray를 비례계수기로 검출하는 기능을 가지고 있다. 이러한 검출 능력을 바탕으로 EXAFS, XANES, Standing Wave Technique, Elemental Composition Analysis, DXRD, Total Reflection Technique 등을 이용하여 물질을 구성하고 있는 원소의 성분, 미세원자구조, 전자구조에 관한 정보를 얻을 수 있는 새로운 spectrometer이다. 본 연구에서는 자체 개발한 XIEES의 XAFS 기능을 이용하여 여러 가지 방법으로 제조한 LiMn2-xO4와 LiMnO2, MnO2에서 Mn K-absorption edge에 대한 chemical state 변화를 측정하였다. Absorption edge에서 chemical shift를 측정하기 위해서는 방사광 가속기 수준의 에너지 분해능(~0.3eV)이 필요하다. 이번 연구에서는 SiO2(3140) monochromator를 사용하고 여기에 맞는 적절한 parameter를 적용하여 x-ray 에너지 분해능을 포항방사광가속기 수준으로 개선하였다. XIEES에서 얻은 스펙트럼과 포항방사광가속기에서 얻은 스펙트럼을 비교하였다. Chemical shift가 일어나는 경향은 두 실험 결과가 잘 일치하였다.

• Journal of the Korean Chemical Society
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• v.28 no.5
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• pp.293-301
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• 1984

-ray fluorescence analysis of $Ta_2O_5$, $Nb_2O_5$ and $ZrO_2$ in tin-slag samples using the simple dilution method was studied. The method is to correct mathematically the calibration curve to the linear line by the dilution. One synthesized standard having similar composition to the sample and tin slag samples were diluted with anhydrous $Li_2B_4O_7$ at the level of 1%, 2% and 3% of the sample content respectively. The diluted samples were fused at $1150^{\circ}C$ for 30 minutes and these glass beads were finely ground and pelletized. Measuring the X-ray intensities with these pellets, analytical results were calculated by the equation derived from J. Scherman's equation for the characteristic X-ray intensity of an element. Analytical results agreed with the reference values obtained by the standard calibration method within allowable error range and were reproducible.

• Analytical Science and Technology
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• v.15 no.6
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• pp.567-573
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• 2002

The most important and largest commercial outlet of fly ash in Korea is a replacement material of Portland cement in concrete industry. The high level of unburned carbon in ash brings about some malfunctions in concrete. Therefore, fly ash is refined to improve the quality as a concrete additive. In this process, a lot of the residual carbon is produced, and discarded now. In the present study, to find out a valuable outlet of the enriched carbon samples, the basic morphology of residual carbon in fly ash from Boryung power plant was investigated. The unburned carbon characterization included shape, size measurement, and chemical analysis was examined using scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDX).