• Title/Summary/Keyword: Mg solid solution

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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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The Mg Solid Solution far the P-type Activation of GaN Thin Films Grown by Metal-Organic Chemical Vapor Deposition

  • Kim, KeungJoo;Chung, SangJo
    • Transactions on Electrical and Electronic Materials
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    • v.2 no.4
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    • pp.24-29
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    • 2001
  • GaN films were grown for various Mg doping concentrations in metal-organic chemical vapor deposition. Below the Mg concentration of 10$^{19}$ ㎤, the thermally annealed sample shows the compensated phase to n-type GaN in Hall measurement. In the MB concentration of 4$\times$10$^{19}$ ㎤ corresponding to the hole carrier concentration of 2.6$\times$1$^{19}$ ㎤ there exists a photoluminescence center of the donor and the acceptor pair transition of the 3.28-eV band. This center is correlated with the defects for a shallow donor of the $V_{Ga}$ and for an acceptor of $Mg_{Ga}$ . The acceptor level shows the binding energy of 0.2-0.25 eV, which was observed by the photon energy of the photocurrent signal of 3.02-3.31 eV. Above the Mg concentration of 4$\times$10$^{19}$ ㎤, both the Mg doping level and Mg concentration were saturated and there Is a photoluminescence center of a deep donor and an acceptor pair transition of the 2.76-eV blue band.

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Analysis of cation ordering and lattice distortion of $(1-x)Ba(Mg_{1/3}Ta_{2/3})O_3-xLa(Mg_{2/3}Ta_{1/3})O_3$ complex perovskite solid solution using powder x-ray diffraction (분말 x선 회절을 통한 $(1-x)Ba(Mg_{1/3}Ta_{2/3})O_3-xLa(Mg_{2/3}Ta_{1/3})O_3$복합페로브스카이트 고용체의 양이온규칙화 및 격자비틀림 분석)

  • Youn, Hyuk-Joon;Ko, Kyung-Hyun;Hong, Kug-Sun;Kim, Hwan
    • Journal of the Korean Ceramic Society
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    • v.34 no.2
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    • pp.175-180
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    • 1997
  • 새로운 복합페로브스카이트계 고용체 (1-x)Ba(Mg1/3Ta2/3)O3-xLa(Mg2/3Ta1/3)O3(x=0.0-1.0)를 설계하고 조성에 따른 고용체의 결정구조의 변화 및 MPB(Morphotropic Phase Boundary)를 분말 XRD를 이용하여 분석하였다. 초격자회절선의 변화로부터 MBT에 10mol%의 LMT를 치환함에 따라 1:2에서 1:1로의 규칙화타입의 전이가 일어남을 알 수 있었다. 면심입방정구조 영역(0.10.8조성의 경우, 주회절선의 피이크분리 및 새로운 회절선들로부터 격자비틀림의 형태가 단사정임을 알 수 있었다.

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Electrical Properties of Gadolinium-doped Ceria/Magnesia (CGO/MgO) Composite Electrolytes (Gadolinium-doped Ceria/Magnesia (CGO/MgO) 복합체 전해질의 전기적 특성 분석)

  • Jo, Seung-Hwan;Muralidharan, P.;Kim, Do-Kyung
    • Korean Journal of Materials Research
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    • v.18 no.9
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    • pp.470-474
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    • 2008
  • Composites of gadolinium-doped ceria/magnesia(CGO/MgO) were synthesized and characterized for the electrolytes of intermediate temperature solid oxide fuel cells. XRD and SEM results revealed that composite electrolytes consisted of their own phases after sintering at $1400^{\circ}C$ without noticeable solid solution of Mg into CGO. As the MgO content increased, the total electrical conductivity decreased, which might be attributed to the decrease of grain boundary conductivity, possibly due to the lowering of the continuity of the CGO grains and blocking effects of the insulating MgO phase. The space charge effect may not be a significant factor to affect the electrical conductivity of the CGO/MgO composites.

Heat Treatment of AZ91-5wt.%Sn Magnesium Alloy (AZ91-5wt.%Sn 마그네슘 합금의 열처리의 특성)

  • Kim, Dae-Hwan;Lim, Su-Gun
    • Journal of Korea Foundry Society
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    • v.37 no.1
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    • pp.14-20
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    • 2017
  • The microstructure, electrical conductivity and hardness variation of an AZ91-5wt%Sn Mg alloy sample during a solid-solution and aging heat treatment were instigated by optical microscopy, scanning electron microscopy, X-ray diffraction and by Rockwell hardness techniques in this study. The XRD result shows that the main phases in the as-casted alloy are ${\alpha}$-Mg, $Mg_{17}Al_{12}$ and $Mg_2Sn$. From the SEM images of the AZ91-5wt%Sn Mg alloy after the solution treatment, the $Mg_{17}Al_{12}$ phases in the alloy were found to have dissolved into the matrix with an increase in the holding time during the solution treatment, but $Mg_2Sn$ phases were clearly observable. The highest peak hardness of the AZ91-5wt%Sn Mg alloy is 82HRE at an aging temperature of $200^{\circ}C$.

A Study on the Development for the Future Compressor Cylinder Block Using of Cold & Hot Forging Method (냉.온간포징법을 이용한 차세대 콤프레샤 실린더 블록 개발에 관한 연구)

  • Kim Soon-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.7
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    • pp.1301-1306
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    • 2006
  • Aluminum alloys are gaining increased acceptance in the automotive and electronic industeries and cold & hot forging is the most efficient method of manufacturing such mass produced parts. This study has been investigated the microstructures and mechanical properties of A6061(Al-1.2Mg-0.8Si) alloy fabricated by cold & hot forging process for development of the future compressor block. The microstructure of cold & hot forginged specimen were composed of eutectic structure aluminum solid solution and $Mg_2Si$ precipitates. The tensile strength of as-solid solution treatment A6061 alloy revealed 291.7MPa. It was fabricated that a trial future compressor cylinder block using cold & hot forging.

A study on the optimized coagulation for separation of liquid and solid from CMP waste (CMP 폐액의 고액 분리를 위한 최적 응집조건에 관한 연구)

  • Hong, Seongho;Oh, Suckhwan
    • Clean Technology
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    • v.7 no.1
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    • pp.27-34
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    • 2001
  • The waste slurry generated from CMP process contains particulate and heavy metals. It is hard to treat the waste slurry by conventional treatment method because the particulates in the waste are too fine to be easily separated the solid from the waste for the purpose of water recycling. The investigation was focused on finding the optimum condition of coagulation with two different coagulants. When the solid content in the waste slurry solution was 0.1wt%, the optimal ranges of pH and PACl concentration were 4~6 and 20~50 mg/L, respectively. When the solid content was increased to 0.5wt%, the optimal condition was 4~5 for pH and 50~100 mg/L for PACl concentration.

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A Hot Melt w/o/w Emulsion Technique Suitable for Improved Loading of Hydrophilic Drugs into Solid Lipid Nanoparticles (현탁된 고형지질나노입자 내로 친수성 약물의 봉입률을 증대시키기 위한 w/o/w 에멀션 가온용융유화법의 평가)

  • Lee, Byoung-Moo;Choi, Sung-Up;Lee, Jae-Hwi;Choi, Young-Wook
    • Journal of Pharmaceutical Investigation
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    • v.35 no.1
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    • pp.33-38
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    • 2005
  • Recently increasing attention has been focused on solid lipid nanoparticles (SLN) as a parenteral drug carrier due to its numerous advantages that can come from both polymeric particle and fat emulsions, together with the possibility of controlled release and increasing drug stability. Lipophilic drugs such as paclitaxel, cyclosporin A, and all-trans retinoic acid have been successfully entrapped in SLN but the incorporation of hydrophilic drugs in SLN is very limited because of their very low affinity to the lipid. Therefore, as a new approach to improve the loading of hydrophilic drugs, a w/o/w emulsion technique has been developed. The primary objective of the current study was to improve the loading efficiency of a model hydrophilic drug, glycine (Log P = -3.44) into SLN. The proposed preparation process is as follows: A heated aqueous phase consisting of 0.1 ml of glycine solution in water (100 mg/ml), and poloxamer 188 (5 mg) were then added to a molten oil phase containing precirol (100 mg) and lecithin (5 mg). This mixture was dispersed by sonicator, leading to a w/o emulsion. A double emulsion (w/o/w) was formed after the addition of 2% poloxamer solution to the above dispersed system. After cooling the double emulsion, solid lipid nanosuspensions were successfully formed. The lipid nanoparticles had the mean particle size of 441.25 nm, and the average zeta potential of -20.98 mV. The drug loading efficiency was measured to be 8.54% and the drug loading amount was measured to be 0.92%. The w/o/w emulsion method showed an increased loading efficiency compared to conventional o/w emulsion method.