• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.245-245
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• 2007

본 연구는 $Bi_2O_3$, ZnO 및 $Nb_2O_5$로 이루어진 두 가지의 $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$와 $(Bi_{1.5}Zn_{0.5})(Zn_{0.5}Nb_{1.5})O_7$ pyrochlore를 제조한 후, ZBS 및 BZBS 유리를 각각 첨가하여 저온 소결 및 마이크로파 유전 특성을 고찰하였다. 두 가지의 pyrochlore에 대하여 하소 온도에 따른 상 합성 유무를 고찰한 결과 $900^{\circ}C$에서 단일 상을 갖는 pyrochlore를 제조할 수 있었다. 두 가지의 pyrochlore에 ZnO-rich ZBS 유리와 $Bi_2O_3$-rich BZBS 유리를 3, 5 wt%로 첨가한 후 $800{\sim}950^{\circ}C$에서 소결한 결과 ZBS 및 BZBS 유리를 5wt%를 첨가하였을 때 $900^{\circ}C$에서 소결이 가능하였다. 또한 마이크로파 유전 특성을 고찰한 결과, $(Bi_{1.5}Zn_{0.5})(Zn_{0.5}Nb_{1.5})O_7$의 pyrochlore는 고주파에서 유전 특성 측정이 되지 않았다. $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$의 pyrochlore의 경우 5 wt% ZBS 및 BZBS 유리를 첨가하여 $900^{\circ}C$에서 소결한 시편의 마이크로파 유전 특성은 ${\varepsilon}_r$= 62.8~68.3, $Q{\times}f$ value= 3,500~2,700 GHz을 나타내었다.

• Korean Journal of Materials Research
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• v.25 no.1
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• pp.43-47
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• 2015

$Zn(BH_4)_2$ was prepared by milling $ZnCl_2$ and $NaBH_4$ in a planetary ball mill in an Ar atmosphere, and XRD analysis, SEM observation, FT-IR analysis, DTA, and TGA were performed for synthesized $Zn(BH_4)_2$ samples. 90 wt% $MgH_2$+1.67 wt% $Zn(BH_4)_2(+NaCl)$+5 wt% Ni+1.67 wt% Ti+1.67 wt% Fe (named $90MgH_2+1.67Zn(BH_4)_2(+NaCl)$+5Ni+1.67Ti+1.67Fe) samples were also prepared by milling in a planetary ball mill in an $H_2$ atmosphere. The gas absorption and release properties of the $Zn(BH_4)_2(+NaCl)$ and $90MgH_2+1.67Zn(BH_4)_2(+NaCl)_2(+NaCl)$+5Ni+1.67Ti+1.67Fe samples were investigated. An FT-IR analysis showed that $Zn(BH_4)_2$ formed in the $Zn(BH_4)_2(+NaCl)$ samples prepared by milling $ZnCl_2$ and $NaBH_4$. At the first cycle at $320^{\circ}C$, $90MgH_2+1.67Zn(BH_4)_2(+NaCl)$+5Ni+1.67Ti+1.67Fe absorbed 2.95 wt% H for 2.5 min and 4.93 wt% H for 60 min under 12 bar $H_2$, and released 1.46 wt% H for 10 min and 4.57 wt% H for 60 min under 1.0 bar $H_2$.

• Mass Spectrometry Letters
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• v.3 no.3
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• pp.82-85
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• 2012

The formation of zinc finger peptide-$Zn^{2+}$ complexes in electrospray ionization mass spectrometry (ESI-MS) was examined using three different metal ion sources: $ZnCl_2$, $Zn(CH_3COO)_2$, and $Zn(OOC(CHOH)_2COO)$. For the four zinc finger peptides (Sp1-1, Sp1-3, CF2II-4, and CF2II-6) that bind only a single $Zn^{2+}$ in the native condition, electrospray of apo-zinc finger in solution containing $ZnCl_2$ or $Zn(CH_3COO)_2$ resulted in the formation of zinc finger-$Zn^{2+}$ complexes with multiple zinc ions. This result suggests the formation of nonspecific zinc finger-$Zn^{2+}$ complexes. Zn(tartrate), $Zn(OOC(CHOH)_2COO)$, mainly produced specific zinc finger-$Zn^{2+}$ complexes with a single zinc ion. This study clearly indicates that tartrate is an excellent counter ion in ESI-MS studies of zinc finger-$Zn^{2+}$ complexes, which prevents the formation of nonspecific zinc finger-$Zn^{2+}$ complexes.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.357-360
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• 2011

N-doped ZnO nanofilms were prepared by plasma enhanced atomic layer deposition method. $Zn(C_{2}H_{5})_{2}$, $O_{2}$ and $N_{2}$ were used as Zn, O and N sources, respectively, for N-doped ZnO films under variation of radio frequency (rf) power from 50-300W. Structural, optical and electrical properties of as-grown ZnO films were investigated with Xray diffraction(XRD), photoluminescence(PL) and Hall-effect measurements, respectively. Nitrogen content and p-type conductivity in ZnO nanofilms increased with the rf power.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.436-439
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• 1997

We investigated a electrical and CO gas sensing properties of pure ZnO and ZnO-ZrO$_2$ composite ceramics. We made 0∼20mo1% ZrO$_2$added ZnO composite ceramics and observed a microstructure of the broken side of the samples. The properties of the samples were studied with temperature, composition, arid a concentration of carbon monoxid. The measured 1000ppm CO sensitivities of pure ZnO were about 1∼1.42, and that of ZnO-ZrO$_2$were about 1∼10.6. In order words, the 1000ppm CO sensitivities of ZnO-ZrO$_2$composite ceramics were about 1∼2 times larger than that of pure ZnO with temperature. The measured 250ppm, 500ppm CO sensitivities of ZnO-ZrO$_2$composite ceramics were about ∼3.28. ∼5.04, respectively.

• Transactions on Electrical and Electronic Materials
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• v.4 no.6
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• pp.13-16
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• 2003

Mn-doped $ZnGa_{2}O_{4}$:$Mn^{2+}$ (M=S, Se) thin film phosphors have been grown using a pulsed laser deposition technique under various growth conditions. The structural characterization carr~ed out on a series of $ZnGa_{2}O_{4}$:$Mn^{2+}$ (M=S, Se) films grown on MgO(l00) substrates usmg Zn-rich ceramic targets. Oxygen pressure was varied from 50 to 200 mTorr and Zn/Ga ratio was the function of oxygen pressure. XRD patterns showed that the lattice constants of the $ZnGa_{2}O_{4}$:$Mn^{2+}$ (M=S, Se) thin film decrease with the substitution of sulfur and selenium for the oxygen in the $ZnGa_2O_4$. Measurements of photoluminescence (PL) properties of $ZnGa_{2}O_{4}$:$Mn^{2+}$ (M=S, Se) thin films have indicated that MgO(100) is one of the most promised substrates for the growth of high quality $ZnGa_2O_{4-x}M_{x}$:$Mn^{2+}$ (M=S, Se) thin films. In particular, the incorporation of Sulfur or Selenium into $ZnGa_2O_4$ lattice could induce a remarkable increase in the intensity of PL. The increasing of green emission intensity was observed with $ZnGa_2O_{3.925}Se_{0.075}:$Mn^{2+}$ and $ZnGa_2O_{3.925}S_{0.05}$:$Mn^{2+}$ films, whose brightness was increased by a factor of 3.1 and 1.4 in comparison with that of $ZnGa_{2}O_{4}$:$Mn^{2+}$ films, respectively. These phosphors may promise for application to the flat panel displays.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.585-591
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• 2018

Characteristics of nano-structured $SiO_2:Zn$ hollow powders prepared in the micro drop fluidized reactor process were investigated with respect to bandgap energy and surface activity. The $SiO_2:Zn$ hollow powders were successfully prepared continuously in the one step process with reasonable production efficiency, with varying the amount of THAM (tris(hydroxymethyl)-aminomethane) additive and concentration of $Zn^{2+}$ ions. The doping of $Zn^{2+}$ ions into $SiO_2$ lattice led to the reduction of bandgap energy by forming the acceptor level of $Zn^{2+}$ below the conduction band of $Si^{4+}$ ions. The hollow shape also contributed to reduce the bandgap energy of $SiO_2:Zn$ powders. The doping of $Zn^{2+}$ ions into $SiO_2$ hollow powders could enhance the surface activity by forming SiO-H stretching and oxygen vacancies at the surface of $SiO_2:Zn$ powders.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1814-1818
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• 1989

The crystals of ZnGa2S4 and ZnGa2S4:Co(2mole%) were synthesized from high-purity (99.999%) elements of Zinc, Gallium, and sulfur. The crystal structure of these crystals belong to a tetragonal system with layer type and the lattice constants are a =5.35\ulcorner c=10.43\ulcornerfor ZnGa2S4: Co(2 mole%) crystal at 298\ulcorner. The optical absorption spectra of these compounds were obtained through reflectance measurements using a 60 mm diameter intergrating sphere. The optical energy gaps are 3.18eV for ZnGa2S4 and 2.60eVfor ZnGa2S4:L Co(2mole%)at 298\ulcorner, respectively.

• Journal of the Korean Ceramic Society
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• v.33 no.5
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• pp.531-535
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• 1996

ZnGa2O4 and Mn-doped ZnGa2O4 were synthesized using the state reaction method to investigate their photoluminescence characteristics depending on Mn concentration. Under 254nm excitation, ZnGa2O4 exhibited a broad-band emission extending from 330 nm to 610 nm peaking at 450nm. On the other hand Mn-doped ZnGa2O4 showed a new strong narrow-band emission peaking at 504 nm and maximum intensity at the doping concentration of 0.006 mole Mn.

• Journal of the Korean Ceramic Society
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• v.13 no.3
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• pp.13-20
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• 1976

The magnetic properties, especially the magnetostriction, of ferroxplana $Zn_{1-x}$$M_X$Y(x=0.0, 0.2, 0.4, 0.6) were investigated at room temperature. In general, the Curie temperature and the permeability of ferroxplana $Zn_{1-X}$$Mn_X$Y increased while the amount of the other phase decrease with increased concentration of dopant $Mn^{2+} for $Zn^{2+}. The magnetostriction constnats K1, K2, K3 and K4 for ZnY were ＋0.3, -5.0, -4.3 and $-4.8{\times}$$10^{-6} while that for 4Zn^0.8$ $Mn^0.2$Y were ＋2.5, -5.4, -6.0 and $-3.4{\times}10^{-6}$, respectively.