• Korean Journal of Materials Research
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• v.7 no.9
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• pp.723-727
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• 1997

Nd치환이 Ag의 용융점 이하인 94$0^{\circ}C$에서 소결한 $Bi_{1-x}$$Nd_{x}$N$bO_{4}$세라믹스의 소결거동과 마이크로파 유전특성에 미치는 영향을 연구하였다. Nd치환량(x)이 증가함에 따라 사방점에서 삼사정으로 변하는 양이 증가하였고 결정립의 크기, 겉보기밀도, 유전상수는 감소하였다. Q$xf_{0}$값은 Nd 치환량이 0.025mole 이하의 경우 큰 변화가 없으나, 그 이상에서는 증가하여 0.1mol일 때 최고값을 보이고 다시 급격히 감소하였다. TCF값은 Nd치환량이 증가할수록(+)방향으로 증가하였다. 가장 우수한 마이크로파 유전특성은 Nd 치환량이 0.025mole일 때 얻어졌으며, 이때 유전상수는 43.7, Qxf/ sub 0/값은 11,046GHz, TCF값은 -1.82ppm/$^{\circ}C$이었다.

• Bulletin of the Korean Chemical Society
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• v.26 no.7
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• pp.1090-1096
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• 2005

$Ag_4Br_4$ nanoclusters have been synthesized in about 75% of the sodalite cavities of fully $K^+$-exchanged zeolite A (LTA). An additional KBr molecule is retained in each large cavity as part of a near square-planar $K_4Br^{3+}$ cation. A single crystal of $Ag_{12}$-A, prepared by the dynamic ion-exchange of $Na_{12}$-A with aqueous 0.05 M $AgNO_3$ and washed with $CH_3OH$, was placed in a stream of flowing 0.05 M KBr in $CH_3OH$ for two days. The crystal structure of the product ($K_9(K_4Br)Si_{12}Al_{12}O_{48}{\cdot}0.75Ag_4Br_4$, a = 12.186(1) $\AA$) was determined at 294 K by single-crystal X-ray diffraction in the space group Pm m. It was refined with all measured reflections to the final error index $R_1$ = 0.080 for the 99 reflections for which $F_o\;{\gt}\;4_{\sigma}\;(F_o)$. The thirteen $K^+$ ions per unit cell are found at three crystallographically distinct positions: eight $K^+$ ions in the large cavity fill the six-ring site, three $K^+$ ions fill the eight-rings, and two $K^+$ ions are opposite four-rings in the large cavity. One bromide ion per unit cell lies opposite a four-ring in the large cavity, held there by two eight-ring and two six-ring $K^+$ ions ($K_4Br^{3+}$). Three $Ag^+$ and three $Br^-$ions per unit cell are found on 3-fold axes in the sodalite unit, indicating the formation of nano-sized $Ag_4Br_4$ clusters (interpenetrating tetrahedra; symmetry $T_d$; diameter ca. 7.9 $\AA$) in 75% of the sodalite units. Each cluster (Ag-Br = 2.93(3) $\AA$) is held in place by the coordination of its four $Ag^+$ ions to the zeolite framework (each $Ag^+$ cation is 2.52(3) $\AA$ from three six-ring oxygens) and by the coordination of its four $Br^-$ ions to $K^+$ ions through six-rings (Br-K = 3.00(4) $\AA$).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.90-96
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• 1994

In this paper, an experiment about the fabrication method of superconductor was made in order to obtain crystal structure by making High T$\sub$C/, superconductor Y$_1$Ba$_2$Cu$_3$O$\sub$x/ to Y$_2$Ba$_1$Cu$_1$O$\sub$x/ of nonsuperconductor phase was added. 211 phase, which can approach crystal structure and growth-orientatoun, was used as seed in the 123 phase which shows the properties of superconductor. Therefore crystal growth effect was able to be attained. And the effect is expected to eleminate thin crack in the growth-process and to improve electrical properties by adding Ag to High T$\sub$c/ superconductor Y$_1$Ba$_2$Cu$_3$O$\sub$x/ combined with Y$_2$Ba$_1$Cu$_1$O$\sub$x/ .

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1299-1300
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• 2007

In this study, low temperature sintering property of (1-x)$TiTe_{3}O_{8}-xMgTiO_{3}$ ceramics were investigated for LTCC application which enable to cofiring with Ag electrode. $TiTe_{3}O_{8}$ mixed with $MgTiO_3$ to improve the temperature property. In the X-ray diffraction patterns, the columbite structure of $TiTe_{3}O_{8}$ phase and ilmenite structure of $MgTiO_3$ phase were coexisted in all specimens. The bulk densities and dielectric constants were decreased with increasing of $MgTiO_3$. However, the quality factors were increased with $MgTiO_3$ addition. Also, TCRF was shifted to negative(-) direction. Microwave dielectric properties of (1-x)$TiTe_{3}O_{8}-xMgTiO_{3}$ ceramics had similar tendency with calculated value by the mixing rule. The dielectric constant, quality factor and TCRF of $05TiTe_{3}O_{8}-0.5MgTiO_{3}$ ceramics sintered at $830^{\circ}C$ for 3h. were 26.19, 43,290GHz and $-3.9ppm/^{\circ}C$, respectively.

• Korean Journal of Crystallography
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• v.11 no.1
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• pp.28-33
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• 2000

The slow of 2,3-bis(2-pyridyl)pyarzine(bpp) with Ag(CF₃CO₂) produces crystalline product suitable for X-ray crystallography. Crystallographic characterization of the crystal (C/sub 32/H/sub 20/-F/sub 6/N/sub 8/O₄Ag₂: triclinic P1, a=8.518(5)Å, b=9.546(2)Å, c=10.632(1)Å, α=81.11(1)°, β=87.61(3)°, γ=75.66(3)°, V=827.5(5)ų, Z=1, R=0.0431) has provided that the complex is a cyclic dimer [Ag(bpp)(CF₃CO₂)]₂. Each bpp ligand connects two tetrahedral silver(I) ions in a tridentate mode (Ag-N, 2.26()-2.43(2)Å), and the trifluoroacetato anion is bonded to each silver(I) atom in a monodentate fashion (Ag-O, 2.38(1); 2.39(2) Å). The skeletal cyclic dimer is stable up to 212℃, and drastically decomposes around this temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.443-443
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• 2008

본 연구에서는 Ga-doped ZnO(GZO)-Ag-GZO 다층 투명전극을 Dual DC magnetron sputtering system을 이용 하여 유리기판 위에 상온에서 제작하여 Ag 두께에 따른 전기적, 광학적, 구조적 특성변화를 조사하였다. Hall effect measurement와 UV/Vis spectrometer로 전기적, 광학적 특성을 분석하였으며, X-ray diffraction(XRD)와FE-SEM분석을 통해 결정성과 표면 특성을 조사하였다. FE-SEM 분석결과 island 형태에서 continuous layer로 박막의 형상이 바뀌면서 다층 투명전극의 전기적, 광학적 특성에 영향을 미치는 것을 알 수 있었다. 본 실험에서 Ag 두께 12 nm에서 가장 최적화되어 유리기판위에 상온에서 증착되었음에도 불구하고 $5.5{\times}{\times}10^{-5}\Omega$-cm, $6\Omega$/sq. 의 매우 낮은 면저항과 비저항을 각각 나타내었고 550 nm 파장에서 87 % 의 높은 광 투과도를 나타내었다. 또한 두께 12 nm의 Ag가 삽입된 다층 투명전극을 polyethylene terephthalate (PET) 기판위에 성막하여 Bending test를 실시하여 0.1% 이하의 매우 낮은 저항변화를 확인함으로써 플렉시블 기반의 디스플레이나 태양전지의 투명 전극으로서의 응용 가능성을 확인하였고 마지막으로 최적화된 다층 투명전극을 유기물태양전지의 애노드에 적용하여 기존 ITO 애노드를 대체할 수 있는 투명전극으로서의 가능성을 제시하였다.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.317.2-317.2
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• 2007

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 1999.02a
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• pp.24-25
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• 1999

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.608-613
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• 2017

We proposed a pyrometallurgical process to achieve gold alloy with an Au content of more than 80wt% from low grade (<35wt%) gold alloys. We performed the heat treatment at a temperature of $1200^{\circ}C$ for 5 hrs using Au35wt%-Ag5wt%-Cu60wt% gold alloys mixed with 1/2 weighed PbO and CaO flux by varying the ratio of PbO/(PbO+CaO) from 0 to 1. We investigated the change in content of the samples with energy dispersive X-ray spectroscopy (EDS) and time of flight secondary ion mass spectrometry (ToF-SIMS). The EDS results showed that the Au content increased from 35.0wt% in the PbO-only sample to 86.7wt% (in the PbO/(PbO+CaO) 1:1 sample), while the other samples achieved more that 84wt%. In addition, the 2/3 flux ratio sample showed the lowest Ag loss into the flux. In the ToF-SIMS results, the PbO only and CaO only fluxes had Au+ peak intensities of 349 and 37, respectively. Although the CaO-only flux might be more favorable considering the loss of Au into the flux, we concluded that the amount of Au lost into the flux could be ignored. Our results imply that that the pyrometallurgical process using a mixed flux is an effective hydrometallurgical process.

• Journal of the Speleological Society of Korea
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• no.76
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• pp.49-55
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• 2006

The submicron $YBa_2Cu_3O_x$ powder was prepared by the sol-gel method. The particle size is distributed from 0.2 to 1.0 ${\mu}m$, which benefits to eliminate the micro-cracks formed in the $YBa_2Cu_3O_x$ films deposited by electrophoresis. The powder was single phase of $YBa_2Cu_3O_x$ examined by X-ray diffraction. In the sol-gel process the citrate gel was formed from citric acid and nitrate solution of $Y_2O_3$, $Ba(NO_3)_2$ and CuO. When pH values were adjusted to 6.4-6.7, $Ba(NO_3)_2$ could be dissolved in the citrate solution completely. Appropriate evaporative temperature of the sol-gel formation is discussed. Acetone is used as electrophoreticsolution, in which some water and iodine (0.2 g/1) and polyethylene glycol (2 vol. %) are added. The concentrations of $YBa_2Cu_3O_x$ powders is 20g/l. The thickness of deposited film could be more than 50 ${\mu}m$ in 3 minutes of depositing time. The most EPD films could be 90K zero resistance and the Jc values were over 1000A/cm2 (0 H, 77 K).