• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.9 s.112
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• pp.860-865
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• 2006

In this paper, a novel tunable inter-digital capacitor using dielectric tunable $Bi_2O_3-ZnO-Nb_2O_5(BZN)$ pyrochlore thin films is proposed. In order to improve the tunability and reduce DC bias voltage using the fringing electric field, the electrodes of the inter-digital capacitor are embedded in the thin film. Designed results using a 2.5 D simulator show that the tunability of the proposed inter-digital capacitor improves by 10 %, compared to the conventional inter-digital capacitor. The proposed IDC, which is based on the simulation results, was fabricated, using the BZN thin film deposited by a reactive RF magnetron sputtering on the on the silicon substrate. The fabricated inter-digital capacitor shows the maximum tunability of 50 % at 5.8 GHz and 18 V DC applied.

• Economic and Environmental Geology
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• v.22 no.3
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• pp.253-266
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• 1989

The Cu-Pb-Zn-Ag hydrothermal vein type deposits which comprise the Dongil and Dong-cheogogsan mines occur within the Cretaceous sedimentary rocks in the Euiseong Basin of the southern Korean peninsula. The ore mineralization is contained within three stage(I,II and III) quartz and calcite veins. Ore minerals occur as dominant chalcopyrite, galena, sphalerite, tetrahedrite and Pb, Ag, Sb and Bi-bearing sulfosalts. Stage I ore minerals were deposited between $400^{\circ}C$ and $200^{\circ}C$ from the fluid with moderate salinities(7.0 to 4.5 eq. wt. % NaCl). Evidence of boiling suggests pressure of less than 150 bars during stage I mineralization. This pressure corresponds to maximum depths of 650 m and 1700 m, respectively, assuming lithostatic and hydrostatic loads. The data on mineralogy, temperature and salinity, together with information on the solubility of Cu complex, suggest that Cu deposition is a result of boiling coupled with declining temperature from $350^{\circ}$ to $250^{\circ}C$ or declining log $a_{o_2}$(from -29.8 to -35.9 atm.)and increasing in pH. Pb, Ag, Sb and Bi-bearing sulfosalts were deposited by cooling and dilution at temperature of less than $250^{\circ}C$ from the ore fluid with less than -35.9 atm. of log $a_{o_2}$.

• Transactions on Electrical and Electronic Materials
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• v.10 no.5
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• pp.152-155
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• 2009

The microstructure and the electrical properties of a ZnO varistor, which was composed of a ZnO-$Bi_2O_3$-$Sb_2O_3$-CoO- $MnO_2$ -NiO-$Nd_2O_3$ system, were investigated at various $Y_2O_3$ addition concentrations. $Y_2O_3$ played a role in the inhibition of the grain growth. As the $Y_2O_3$ content increased, the average grain size decreased from $6.8{\mu}m$ to $4{\mu}m$, and the varistor voltage($V_{1mA}$) greatly increased from 275 to 400 V/mm. The nonlinearity coefficient ($\alpha$) decreased from 72 to 65 with increasing $Y_2O_3$ amount. On the other hand, the leakage current ($I_L$) increased from 0.2 to 0.9 ${\mu}A$. These results confirmed that doping the varistors with $Y_2O_3$ is a promising production route for production of a higher fine-grained varistor voltage ($V_{1mA}$) which can dramatically reduce the size of the varistors.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.8
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• pp.614-619
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• 2013

Recently, remote phosphor is reported for white LED enhancing of phosphor efficiency compared with conventional phosphor-based W-LED. In this study, Remote phosphor was produced by screen printing coating on glass substrate with phosphor contents rated paste and heat treatment. The paste consists of phosphor, lowest softening glass frit and organic binders. Remote phosphor can be well controlled by varying the phosphor content rated paste. After mounting remote phosphor on top of blue LED chip, CCT, CRI, and luminance efficiency were measured. The measurement results showed that CCT, CRI, and luminance efficiency were 6,645, 68, and 1,16l m/W in phosphor 80 wt.% remote phosphor sintered at $600^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12S
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• pp.1205-1209
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• 2003

We investigated the effects of calcination temperatures on the sintering behaviors and microwave dielectric Properties of (Z $n_{0.8}$M $g_{0.2}$)Ti $O_3$ system. Highly densified samples were obtained at the sintering temperatures below 100$0^{\circ}C$ with additions of 0.45 wt.%B $i_2$ $O_3$ and 0.55 wt.% $V_2$ $O_{5}$. From the examination of the existing phases and microstructures before and after sintering of (Z $n_{0.8}$M $g_{0.2}$)Ti $O_3$ system which is calcined at the various temperatures ranging from 80$0^{\circ}C$ to 100$0^{\circ}C$, it was found that higher Q${\times}$ $f_{o}$ values were obtained when unreacted phases in calcined body were reduced. When calcined at 100$0^{\circ}C$ and sintered at 90$0^{\circ}C$, it consists of hexagonal as. a main phase with uniform microstructure and exhibits Q${\times}$ $f_{o}$ value of 42,000 GHz and dielectric constant of 22. 22. 22.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.178.2-178.2
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• 2015

In and Ga doped ZnO (IGZO) films were deposited on 5 nm thick Cu film buffered Polycarbonate (PC) substrates with RF magnetron sputtering and then the effect of Cu buffer layer on the optical and electrical properties of the films was investigated. While IGZO single layer films show the electrical resistivity of $1.2{\times}10-1{\Omega}cm$, IGZO/Cu bi-layered films show a lower resistivity of $1.6{\times}10-3{\Omega}cm$. Although the optical transmittance of the films in a visible wave length range is deteriorated by Cu buffer layer, IGZO films with 5 nm thick Cu buffer layer show the higher figure of merit of $2.6{\times}10-4{\Omega}-1$ than that of the IGZO single layer films due to the enhanced opto-electrical performance of the IGZO/Cu bi-layered films.

• Transactions on Electrical and Electronic Materials
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• v.13 no.4
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• pp.185-187
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• 2012

Ga doped ZnO (GZO)/copper (Cu) bi-layered film was deposited on glass substrate by RF and DC magnetron sputtering and then the effect of the Cu bottom layer on the optical, electrical and structural properties of GZO films were considered. As-deposited 100 nm thick GZO films had an optical transmittance of 82% in the visible wavelength region and a sheet resistance of 4139 ${\Omega}/{\Box}$, while the GZO/Cu film had optical and electrical properties that were influenced by the Cu bottom layer. GZO films with 5 nm thick Cu film show the lower sheet resistance of 268 ${\Omega}/{\Box}$ and an optical transmittance of 65% due to increased optical absorption by the Cu metallic bottom layer. Based on the figure of merit, it can be concluded that the thin Cu bottom layer effectively increases the performance of GZO films as a transparent and conducting electrode without intentional substrate heating or a post deposition annealing process.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1697-1702
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• 2014

A novel complex [$Zn(phen)(o-AB)_2$] [phen: 1,10-phenanthroline o-AB: o-aminobenzoic acid] was synthesized and characterized by elemental analysis and X-ray diffraction single-crystal analysis. The crystal crystallizes in monoclinic, space group P2(1)/c with $a=7.6397(6){\AA}$, $b=16.8761(18){\AA}$, $c=17.7713(19){\AA}$, ${\alpha}=90^{\circ}$, ${\beta}=98.9570(10)^{\circ}$, ${\gamma}=90^{\circ}$, $V=2.2633(4)nm^3$, Z = 4, F(000) = 1064, S = 1.058, $Dc=1.520g{\cdot}cm^{-3}$, $R_1=0.0412$, $wR_2=0.0948$, ${\mu}=1.128mm^{-1}$. The Zn(II) is six coordinated by two nitrogen and four oxygen atoms from the 1,10-phenanthroline and o-aminobenzoic acid to furnish a distorted octahedron geometry. The complex exhibits intense fluorescence at room temperature. Theoretical studies of the title complex were carried out by density functional theory (DFT) B3LYP method. CCDC: 898291.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.3
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• pp.227-231
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• 2008

In this study, in order to improve the electrical properties of low temperature sintering piezoelectric ceramics, $[0.05Pb(Zn_{1/2}W_{1/2})-0.07Pb(Mn_{1/3}Nb_{2/3})-0.088Pb(Zr_{0.48}Ti_{0.52})]O_3$(abbreviated as PZW-PMN-PZT) ceramic systems were fabricated using $Bi_2O_3$, CuO and $Li_2CO_3$ as sintering aids and then their piezoelectric and dielectric properties were investigated according to the amount of $Li_2CO_3$ and post-annealing process. Post-annealing process enhanced all physical properties except for mechanical quality factor (Qm). 0.2 wt% $Li_2CO_3$ added and post-annealed specimen showed the excellent values suitable for low loss piezoelectric actuator application as follow: the density = 7.86 $g/cm^3$ electromechanical coupling factor (kp) = 0.575, piezoelectric constant $d_{33}$ = 370 pC/N, dielectric constant ($\varepsilon_r$) = 1546, and mechanical quality factor (Qm) = 1161, respectively.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.298-301
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• 1988

In this paper, we describes Faraday effect of BSO and ZnSe single crystals. By using intensity modulation, we detected. Faraday angle of light beam in these crystals and our current measurement system shows excellent linear characteristics by setting up circular core on a conductor.