• Analytical Science and Technology
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• v.6 no.5
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• pp.479-487
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• 1993

Potassium-Graphite Fiber Intercalation Compounds(K-GFIC) have been prepared from well oriented pitch-based Graphite fiber by the transformed two-bulbs method with variation of reaction temperatures of graphite($T_g$ : $450^{\circ}C$, $400^{\circ}C$, $350^{\circ}C$, $300^{\circ}C$, $250^{\circ}C$). The stage transition process of K-GFICs was studied by X-ray diffraction methods, and we have observed peaks with d-values of (001) diffraction of $5.40{\AA}$ and $8.78({\pm}0.01){\AA}$, which are charecteristic for the stage 1 and stage 2, respectively. The stage stability and energy states of K-GFICs were studied by UV/VIS spectrophotometer. As a results, We found that the minimum values of reflactance of K-GFICs with pure stage was moved to higher energy pristine Graphite fiber's. But because of mixtured stage, we could not observe minimum reflectance in the visible region at high reaction temperatures($400^{\circ}C$, $450^{\circ}C$). From X-ray diffraction and UV/VIS sepctrophotometry data, we can suggest that K-GFICs with lower stage has many charge carriers existed between C atoms of graphite Layers. And then, these results also provides information on the electrical and other physical properties of K-GFICs.

• Korean Journal of Materials Research
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• v.7 no.12
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• pp.1041-1046
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• 1997

본 연구에서는 분자선 에피택시 방법으로 비대칭 AIAs/GaAs(001)이중 장벽, 삼중장벽구조를 성장한 수 이를 이용하여 2단자 소자를 제작하여 전기적 특성을 분석하였다. 에피층은 쌍결정 X-ray회절 분석과 단면투과 전자현미경을 이용하여 결정성 및 격자 정합성을 확인하였다. 전기적 성능을 보다 향상시키기 위해 n-GaAs에 대한 오믹 접촉등의 소자 제작 공정을 최적화하였다. 삼중장벽 구조를 이용하여 제작한 소자의 전기적 특성 연구 결과 두개의 주요 공진 터널링 전류 피크 사이에 X-valley에 의한 구조를 확인할 수 있었으며, 이중 장벽구조에 제2의 양자우물 구조를 첨가함으로써 낮은 전압위치에서 전류 피크가 향상하는 결과를 얻었다.

• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.305-314
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• 2002

The dehydration of hexadecyltrimethylammonium (HDTMA)-exchanged montmorillonite has been studied using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The dehydration in HDTMA-montmorillonite seems to influence the swelling behavior of the organo-clay during heating. The basal d(001) spacing vs temperature curve of the HDTMA-montmorillonite has one broad swelling edge with a shoulder on the low-temperature side. We believe that the shoulder at $100^{\circ}C$ for the HDTMA-montmorillonite is due to interlayer swelling induced by the initial rearrangement of surfactants, and the second edge at $200^{\circ}C$ is caused by interlayer swelling resulting from the secondary vertical reorientation of alkyl chains. It seems that the dehydration of organo-clay induces a reorientation of the alkyl chains by transition to more vertical position relative to the silicate sheets, allowing instantly greater d-spacing.

• Journal of Sericultural and Entomological Science
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• v.27 no.2
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• pp.28-39
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• 1985

The structural and useful characteristics of silk habutae treated with silicone resin by emulsion finishing method were studied. The results were obtained through crease recovery test, water repellency test, scanning micrograph observation, amino acid analysis, X-Ray diffraction analysis, and Fourier Transform Infrared Spectroscopy. The results are summarized as follows; 1) The improvement in crease recovery of silk habutae finished with silicone resin, was observed b soaping treatment and curing conditions. 2) The higher water repellency and stiffness in silk fabrics finished with silicone resin was found by the fabric inspection and the scanning electron microscopic observation. It is suggested that silicone resin impregnated into the void of silk fibroin. 3) The polar side chains of amino acid composition were decreased, when the silicone resin was treated on silk fibroin. 4) Through Amino acid analysis of silicone resin finished fibroin, the different amounts of amino acid composition was indicated due to silk fibroin silicone polymer reaction and the structural difference of its fibroin were also proved by X-ray diffractograms. 5) The functionality of the siloxane compound may be deduced from the silicone finished silk habutae by Fourier Transform Spectroscopy. It was concluded from the above results that the useful characteristics of silk fabric can be improved by silicone resin finishing.

• Journal of the Mineralogical Society of Korea
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• v.18 no.4 s.46
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• pp.259-266
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• 2005

X-ray diffraction (XRD), Electron microprobe analyses (EPMA) and heating experiments were used for mineralogical characterization of natural buserites collected from the Janggun and Dongnam mines. They are closely associated with $7-{\AA}$ phase (usually rancieite) in manganese oxide ores of the supergene oxidation zones of manganese carbonate deposits. Electron microprobe analyses give the average formula $(Ca_{0.78}Mg_{0.64}Mn^{2+}\;_{0.45})Mn^{4+}\;_{8.03}O_{18}\cdot13.2H_{2}O\;and\;(Zn_{0.81}Ca_{0.77}Mg_{0.26})Mn^{4+}\;_{8.00}O_{18}\cdot10.9H_{2}O$ for buserite from the Janggun and the Dongnam mine, respectively. The basal reflection of buserite from the Janggun mine shifts continuously from $9.86\;{\AA}\;at\;40^{\circ}C\;to\;7.60\;{\AA}\;at\;90^{\circ}C$, but the buserite from the Dongnam mine shows tendency of decreasing intensity in the $9.67^{\circ}C$ peak and of increasing intensity in the $7.53\;{\AA}$ peak in the range of $40\∼90^{\circ}C$, showing no gradual shifting of peaks.

• Korean Journal of Materials Research
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• v.8 no.4
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• pp.328-336
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• 1998

In metal-carbon system with no mutual solubility between matrix and alloying elements as solid or liquid phases, Cu-C-X nanocomposite metal powders were prepared by high energy ball milling for solid-lubricating bronze bearings. Elemental powder mixtures of Cu-lOwt.%C- 5wt. %Fe and Cu- lOwt. %C- 5wt. %Al were mechanically alloyed with an attritor in an argon atmosphere, and then microstructural evolution of the Cu-C-X nanocomposite metal powders was examined. It has been found that after 10 hours of MA, the approximately 10$\mu\textrm{m}$ sized Cu-C- X nanocomposite metal powders can be produced in both compositions. Morphological characteristics and microstructural evolution of the Cu-C-X powders have shown a similar MA procedure compared to those of metal-metal system. As a result of X - ray diffraction analysis, diffraction peaks of Cu and C were broaden and peak intensities were decreased as a function of MA time. Especially, the gradual disappearance of C peaks in the X- ray spectra is proved to be due to the lower atomic scattering factor of C. The calculated Cu crystallite sizes in Cu- C- X nanocomposite metal powders by Williamson- Hall equation were about lOnm size, on the other hand, the observed ones by TEM were in the range of 10 to 30nm.

• Analytical Science and Technology
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• v.5 no.1
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• pp.115-120
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• 1992

The upper limit of solid solution of $Al_2O_3$ in $LiTaO_3$ was investigated using X-ray diffraction and Raman spectroscopy. By substituting cations in $LiTaO_3$ with $Al^{3+}$, the melting temperature was lowed and the ferroelectric properties can be improved. It is easier at lower temperature to fabricate the single crystal used for SAW filters and IR sensors. From the measured lattice constants and Raman band broadening, the solubility limit was X=0.25mol in $Li_{1-X}Al_{2X}Ta{1-X}O_3$, above which $Al_2O_3$ was obsered as a second phase. The Raman band of sintered $LiTaO_3$ was compared with that of the single crystal to see the effect of grain size on the band broadening.

• Journal of the Korean Magnetics Society
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• v.14 no.2
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• pp.71-75
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• 2004

$\alpha$-LiFe $O_2$ powders have been prepared by a sol-gel method. The crystallographic and magnetic properties were characterized with a x-ray diffractometry, Mossbauer spectroscopy, and vibrating Samples magnetometry. The ${\gamma}$-LiFe $O_2$+LiFe$_{5}$ $O_{8}$ phase is observed in the Samples annealed at $600^{\circ}C$ for 3h in air and $\alpha$-LiFe $O_2$ phase is observed in the Samples annealed at $600^{\circ}C$ for 3 h in $H_2$(5％)/Ar(Bal.) gas atmosphere. The crystal structure of $\alpha$-LiFe $O_2$ is found to be cubic with a lattice a=4.193$\pm$0.0005 $\AA$. The Neel temperature of $\alpha$-LiFe $O_2$ is found to be 130$\pm$3 K.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.10a
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• pp.173-179
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• 1997

출발원료로 ferric nitrate, ethylene glycol, acethyl acetone 혼합용액을 사용하여 dip-coating된 $\alpha$-Fe$_2$O$_3$막을 제조하였다. coating을 위한 혼합용액의 시간의 경과에 따른 용액내의 가교(polymerization) 효과를 관찰하기 위해서 적외선 분광기(FT-IR)을 사용하였고, 막 형성 시 유기물 분해 및 결정화 시작 온도를 확인하기 위하여 FT-IR, XRD, DSC 등을 이용하여 분석을 행하였다. 또한 각 조건에서 제조된 막은 X-선 회절 분석을 통해 결정상을 확인 하였으며, SEM을 통하여 막의 두께 변화에 대하여 관찰하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.64-64
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• 2013

아연(Zn)을 대체할 수 있는 물질계 인 알루미늄(Al)과 마그네슘(Mg)을 본 연구에서는 E-beam 증착을 이용하여 냉연강판 위에 코팅하고 열처리를 실시하여 전자현미경 및 X-선 회절분석을 이용한 코팅층의 특성 분석 및 염수분무시험을 통해 내식성을 평가하였다.