• Title/Summary/Keyword: X-ray diffraction patterns

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The Dependence of Electrical Conductivity of Cupric Oxide on Temperature (산화동에 있어 온도변화에 의한 전기전도도에 관한 연구)

  • 안영필;이희동
    • Journal of the Korean Ceramic Society
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    • v.20 no.2
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    • pp.161-165
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    • 1983
  • We studied the dependence of electrical conduction mechanism of Cupric Oxide on temperature and measured the specific resistivity of sintered specimen from $600^{\circ}C$ to 90$0^{\circ}C$ . We considered the relations between electrical conducti-vityand temperature with reheating the sintered specimen. X-Ray diffraction patterns showed that lattice parameters of cupric oxide increased above 20$0^{\circ}C$. Cupric oxide had nostoichiometric compositions$(CuO_{1+x})$ owing to the excess oxygen and showed hole conduction with energy gap of 0.15eV below $650^{\circ}C$$\pm$1$0^{\circ}C$ Above $650^{\circ}C$$\pm$1$0^{\circ}C$ cupic oxide had the stoichiometric composition and showed electron-hole conduction owing to the intrinsic ionization with energy gap of 1.04V.

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Mullitization of Al-Kaolin Mixture (Al-Kaolin 혼합물의 Mullite화 반응)

  • 박정현;조정식;배원태
    • Journal of the Korean Ceramic Society
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    • v.20 no.2
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    • pp.123-128
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    • 1983
  • This research is aimed to synthesize the mullite by adding Al powder of $Al_2O_3$ to kaolin. Specimens fired at 1400, 1450 and 150$0^{\circ}C$ were compared in their X-ray diffraction patterns quantitative analysis of mullite formed and fine microstructures with those containing reactive $Al_2O_3$ activated $Al_2O_3$ as alumina source The experiment of Al oxdiation was also performed by measuring the weight increase of specimens. Two different shapes of mullites acicular and chunky were observed by SEM and the yield of mullites were in-creased by the order of adding activated $Al_2O_3$ reactive $Al_2O_3$ and Al powder to kaolin.

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A Study on the Dielectric Properties of PZT Ceramics with 2 and 6 Valent Additives (2가 및 6가의 첨가제에 따른 PZT 자기의 유전적 성질에 관한 연구)

  • 안영필;이기옥
    • Journal of the Korean Ceramic Society
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    • v.20 no.1
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    • pp.19-24
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    • 1983
  • Dielectrics used as capacitor was studied in the system of $Pb(MgW)_{0.5} O_3-PbTiO_3-PbZrO_3$ Curie tempera-tures of $PbTiO_3 PbZrO_3$ and $Pb[MgW]_{0.5} O_3$ were 49$0^{\circ}C$ 23$0^{\circ}C$ and 39$0^{\circ}C$ respectively. When these materials formed solid solution the more amount of $Pb(MgW)_{0.5}O_3$ was increased the more Curie temperature lowered and dielectric constant increased. Higher dielectric constants were measured in the solid solution of which X-Ray diffraction patterns were changed. Especially Curie temperature and dielectric constant were 85$^{\circ}C$ and 4159 respectively in the composition of 60 $Pb(MgW)_{0.5}O_3-30 PbTiO_3-10PbZrO_3$. Also in this composition ferroeletric material with thermal stability was obtained.

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Synthesis and Sintering of Cordierite from Metal Alkoxides(I) -Synthesis of Cordierite from Metal Alkoxides- (금속 Alkoxide로부터 Cordierite 분말의 합성 및 소결에 관한 연구(I) -금속 Alkoxide로부터 Cordierite분말의 합성-)

  • 한문희;박금철
    • Journal of the Korean Ceramic Society
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    • v.27 no.5
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    • pp.625-630
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    • 1990
  • Cordierite powders were prepared from Si(OC2H5)4, Al(OC3H7i)3 and Mg(OC2H5)2 by the sol-gel method. Two different methods were applied for producing fine and homogeneous powders. One is that Si(OC2H5)4 with a lowr rate of hydrolysis was partially hydrolyzed and then Al(OC3H7i)3 and Mg(OC2H5)2 were mixed and reacted. The other is based on the simultaneous hydrolysis of these metal alkoxides using i-C4H9OH which retards the rate of hydrolysis of Al(OC3H7i)3 and Mg(OC2H5)2. It was confirmed that ifne and homogeneous powders were obtained from both methods. Also these powders were calcined at four different temperatures during two hours. X-ray diffraction patterns show only ${\mu}$-cordierite phase at 1000$^{\circ}C$, ${\mu}$-cordierite and ${\alpha}$-cordierite phases at 1100-1200$^{\circ}C$ and ${\alpha}$-cordierite phase at 1300$^{\circ}C$ respectively.

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The fabrication and properties of ${YBa}_{2}{Cu}_{3}{O}_{7-x}$ thin films by laser ablation (레이저 어브레이션법에 의한 ${YBa}_{2}{Cu}_{3}{O}_{7-x}$ 박막의 제조와 특성)

  • 이덕출;최충석
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.44 no.8
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    • pp.1063-1067
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    • 1995
  • The superconducting properties of YBa$_{2}$Cu$_{3}$$O_{7-x}$(YBaCuO) thin films prepared by laser ablation have been investigated. The x-ray diffraction patterns and surface morphology of the films were substantially different from one another. The compositional ratios of YBaCuO films were controlled by the conditions of the target-substrate distance. The YBaCuO films manufactured on MgO(100) substrate were indicated T$_{c}$(zero)=91.2 K, T$_{c}$(onset)=93 K, and J$_{c}$=3.5*10$^{5}$ A/cm$^{2}$(at 77.3K). The optimum conditions were found to be a substrate temperature of 710 .deg. C, a energy density of 2 J/cm$^{2}$, and a target-substrate distance of 60 mm in an oxygen partial pressure of 200 mTorr.0 mTorr.

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Effect of additives on surface properties of Zn-Ni alloy Coating (Zn-Ni 합금전기도금강판의 표면특성에 미치는 첨가제 영향)

  • 김현태;장삼규;정원섭
    • Journal of the Korean institute of surface engineering
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    • v.31 no.4
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    • pp.191-198
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    • 1998
  • The effect of the additives on the Zn-Ni alloy electrocrystallization from a chloride bath was investigated by means of electrochemical methodes, scanning electron microscopy and measurement of surface appearancd, X-ray diffraction patterns. The additives thestd ware the Saccharin, surfactant of naptalene-derivative and mixed additive, The resistance of electrodeposit increased by adding the additives, whera the effect of additives on resistance was different with current density roughness, apperarance and morphology of deposit were also influenced by the type of additive. The deposir with fine, compact grains as well as good surface roughness and appearance was obtained from the mixed-additive added bath.

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Fabrication of Textured $Al_2O_3-Mullite-SiC$ Nano-composite by Slip Casting in a High Magnetic Field and Reaction Sintering

  • Sakka, Yoshio;Saito, Sho;Honda, Atsushi;Suzuki, Tohru S.;Moriyoshi, Yusuke
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.327-328
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    • 2006
  • We have demonstrated that textured $Al_2O_3-mullite-SiC$ nanocomposites can be fabricated by slip casting followed by partial oxidation - reaction sintering of mixed suspensions of $Al_2O_3$ and SiC powders in a high magnetic field. The sintered density was changed by the degree of oxidation at 1200C and 1300C. The degree of orientation of alumina in the nanocomposite was examined on the basis of the X-ray diffraction patterns and scanning electron micrographs. It is confirmed that alumina-oriented nanocomposites were fabricated. The three-point bending strength at room temperature was observed for the nanocomposites.

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Fabrication of Textured $Al_2O_3-Mullite-SiC$ Nano-composite by Slip Casting in a High Magnetic Field and Reaction Sintering

  • Sakka, Yoshio;Saito, Sho;Honda, Atsushi;Suzuki, Tohru S.;Moriyoshi, Yusuke
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.455-456
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    • 2006
  • We have demonstrated that textured $Al_2O_3-mullite-SiC$ nanocomposites can be fabricated by slip casting followed by partial oxidation. reaction sintering of mixed suspensions of $Al_2O_3$ and SiC powders in a high magnetic field. The sintered density was changed by the degree of oxidation at 1200C and 1300C. The degree of orientation of alumina in the nanocomposite was examined on the basis of the X-ray diffraction patterns and scanning electron micrographs. It is confirmed that aluminaoriented nanocomposites were fabricated. The three-point bending strength at room temperature was observed for the nanocomposites.

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Electrical Breakdown Properties of Highly Elongated Polyethylene (고연신(高延伸)Polyethylene의 절연파괴특성(絶緣破壞特性))

  • Park, Dae-Hee;Kim, Dong-Wook;Kang, Sung-Hwa;Lim, Kee-Joe
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.1209-1211
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    • 1993
  • In this paper, the relationship between electrical breakdown properties and the molecular orientation owing to elongation was investigation from electrical conductivity, electrical breakdown strength and X-ray diffraction wag investigated. The changes of the stretching direction, from an a-axis orientation(at high elongation) to a c-axis orientation(at high elongation), as the elongation increases, were determined from X-ray diffraction patterns. These results suggest that the tendency for a decrease in the trap density at a higher elongation is consistent with a continuous change of the reorientation from the a-axis to the c-axis as the elongation increases.

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Self-poling Mechanism of CNT/PVDF Piezoelectric Composite Films Prepared by Spray Coating Method (스프레이 코팅법으로 제조된 CNT/PVDF 압전 복합막의 자기분극 메커니즘)

  • Lee, Sunwoo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.7
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    • pp.550-554
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    • 2013
  • Carbon nanotubes (CNT) / polyvinylidene fluoride (PVDF) piezoelectric composite films for nanogenerator devices were fabricated by spray coating method. When the CNT/PVDF mixture solution passes through the spray nozzle with small diameter by the compressed nitrogen gas, electric charges are generated in the liquid by a triboelectric effect. Then randomly distributed ${\beta}$ phase PVDF film could be re-oriented by the electric field resulting from the accumulated electrical charges, and might be resulted in extremely one-directionally aligned ${\beta}$ phase PVDF film without additional electric field for poling. X-ray diffraction patterns were used to investigate crystal structure of the CNT/PVDF composite films. It was confirmed that they revealed extremely large portion of the ${\beta}$ phase PVDF crystalline in the film. Therefore we could obtain the poled CNT/PVDF piezoelectric composite films by the spray coating method without additional poling process.