• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.873-877
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• 2007

In order to apply a complex multilayer chip LC filter, this study has estimated the interfacial reaction and coupling properties of dielectric materials $Pb(Fe_{1/2}Nb_{1/2})O_3$ and Ni-Zn-Cu ferrite materials through low-temperature co-sintering (LTCS). PFN powders were fabricated using double calcinated at $700^{\circ}C$ and then $850^{\circ}C$. While the perovskite phase rate was found to be 91 %, after heat treatment at $900^{\circ}C$ for 6h, the perovskite phase rate and density exhibited a value of 100 % and 7.46$g/cm^3$, respectively. The PFN/Ni-Zn-Cu ferrite, PFN/CUO (or $Pb_2Fe_2O_5$) and ferrite/CuO (or $Pb_2Fe_2O_5$) were mechanically coupled through interfacial reactions after the specimen was co-sintered at $900^{\circ}C$ for 6 h. No intermediate layer exists for the mutual coupling reaction. This result indicates the possibility of low-temperature co-sintering without any interfacial reaction layer for a multilayer chip LC filter.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.191.2-191.2
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• 2014

Cu/ZnO/$Al_2O_3$ is widely used methanol synthesis catalyst at elevated pressures P (50 to 100 bar) and temperatures T (473 to 573 K) using $CO_2$, CO, $H_2$ syngas mixture. Although Cu step and planar defects have been regarded as active sites in this catalyst, detailed $CO_2$ hydrogenation procedure has been still unknown and debated as well as initial intermediate. In this study, we investigated the mechanism of $CO_2$ hydrogenation on Cu(111) model surface at P (1 bar) and T (298 to 450 K) using reflection absorption infrared spectroscopy (RAIRS). Two distinct formates by hydrogenation of $CO_2$, on step and on terrace, show different behavior with elevating temperature. The peak intensity of on step formate was continuously decreased above 360 K up to 450K in contrast to the increase of on terrace formate. These phenomena are strong possibilities that the formate is initial intermediate and is desorbed by hydrogenation reaction because thermal desorption temperature of formate (~470 K) is much higher than desorption of on step formate. And the formate production peak of on step site was weakly correlated with CO formation.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.4
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• pp.555-562
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• 1990

Alloyed ohmic contact properties of Au-Zn/Au, Au-Be/Au,Au-Zn/Cr/Au, and Au-Be/Cr/Au metal system to p-InP were investigated. Optimum alloying conditions were obtained at the annealing temperature of 425\ulcorner for all the metal systems using a rapid thermal annealing system. Surface AES analysis and auger depth profiling were done for each metal system annealed at the optimum conditions. Outdiffusions of In and P from the InP substrate were found in the metal systems without Cr intermediate layer. Also, small amount of In. P and Cr were detected at the surface in the case of Au-Zn/Cr/Au system, while there were occured no outdiffusion of In, P, and Cr for Au-Be/Cr/Au system. The best surface morpholoty and specific contact resistivity of 4.5x 10**-5 \ulcornercm\ulcornerhave been obtained in this Au-Be/Cr/Au material system alloyed at 425\ulcorner for 60 second.

• Journal of Technologic Dentistry
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• v.31 no.3
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• pp.15-20
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• 2009

The success of the porcelain fused to gold alloy restoration depends not only on the choice of materials but to a larger degree on the technical skills. The porcelain fused to metal(PFM) alloys containing gold are commonly use for dental purposes in dental laboratory. The gold-colored alloys contain primarily gold, platinum, palladium, and silver, with minimum amounts of such metals as tin, iridium, or titanium. The purpose of this study is on the metal-porcelain fusing layer in porcelain fused to high gold alloy Principal results are as follows. The hardness number(Hv) of PFG is respectively $140.2{\pm}12.6$ in as-casted, $164.3{\pm}14.3$ in heat-treated, $186.6{\pm}20.4$ in fired-treated. The formation of the fusing(intermediate) layer caused by components fusing the interface of porcelain and gold alloy. The main components of the fusing(intermediate) layer are Na, Al, Si, K, Zn, Zr and Ce. The intermediate layer formed by the 2nd firing is more larger than the intermediate layer formed by the 1st firing.

• Journal of the Korean institute of surface engineering
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• v.53 no.3
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• pp.104-108
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• 2020

ZnO single layer films (100 nm thick) and Au intermediated ZnO films (ZnO/Au/ZnO; ZAZ) were deposited on the glass substrate by RF and DC magnetron sputtering at room temperature and then the influence of the Au interlayer on the electrical and optical properties of the films were investigated. ZnO thin films show the visible transmittance of 90.3 % and sheet resistance of 63.2×10⁸ Ω/□. In ZAZ films, as Au interlayer thickness increased from 6 to 10 nm, the sheet resistance decreased from 58.3×10⁸ to 48.6 Ω/□, and the visible transmittance decreased from 84.2 to 73.9 %. From the observed results, it can be concluded that the intermediate Au thin film enhances the opto-electrical performance of ZnO films without intentional substrate heating.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.2
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• pp.74-79
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• 2015

$Na-ZnCl_2$ battery, which operates as the same mechanism of $Na-NiCl_2$ battery using solid-electrolyte, is able to reduce its material cost by 40 % comparing to the $Na-NiCl_2$ battery. It has been known that the $Na-ZnCl_2$ battery produces $Na_2ZnCl_4$ as an intermediate phase during charge/discharge process. Therefore, the redox process is divided into four steps having the voltage range of 1.92~2.13 V. However, effects of the critical factors such as the composition of cathode materials, depth of charge and discharge, and additives have not been reported yet. We examined the effect of the Zn/NaCl ratios and revealed that its optimum ratio was in the range of 1.3~1.7.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.1057-1065
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• 2010

Two experiments were conducted to compare the effects of feeding a newly-developed rare earth mineral-yeast product, zinc oxide (ZnO) or antibiotics on the performance, nutrient digestibility and serum parameters of weanling pigs. In experiment 1, 150 crossbred barrows (24 d old and 6.28 kg BW) were fed one of five dietary treatments consisting of an unsupplemented basal diet or the basal diet supplemented with antibiotics (33 ppm tiamulin and 100 ppm chlortetracycline), ZnO (1,500 or 2,500 ppm) or 0.1% peptide-bound rare earth mineral-yeast. In experiment 2, 576 crossbred barrows (28 d old and 7.20 kg BW) were fed the same diets as those used in experiment 1 modified only by the addition of 1.0% Celite 545 to all diets as a digestibility marker. However, the negative control was not included. In experiment 1, weight gain was significantly lower (p<0.05) for pigs fed the negative control than for pigs fed diets supplemented with antibiotics, ZnO, or rare earth mineral-yeast. Pig performance did not differ between pigs fed the four supplemented diets. In experiment 2, there were no differences in performance between pigs fed diets supplemented with antibiotic, ZnO or rare earth mineral-yeast. The digestibility of dry matter, crude protein, calcium, phosphorus and energy were significantly (p<0.01) higher on the rare earth mineral-yeast diet than on diets supplemented with ZnO. In addition, pigs fed the diet supplemented with rare earth mineral-yeast had significantly (p<0.05) higher digestibility of histidine, lysine, threonine and valine than pigs fed the ZnO supplemented diets. Digestibility coefficients for pigs fed antibiotics tended to be intermediate to those of pigs fed rare earth mineralyeast or ZnO. In conclusion, the performance of pigs fed rare earth mineral-yeast was basically equal to that of pigs fed antibiotics or ZnO indicating that rare earth mineral-yeast can be successfully used as a growth promoter in diets fed to nursery pigs. The effects of rare earth mineral-yeast appeared to be mediated through improvements in nutrient digestibility.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.4
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• pp.592-598
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• 1998

AZO(Aluminum doped Zinc Oxide) thin films were fabricated by reactive DC magnetron sputtering method using zinc metal target (Al 2%) and zinc oxide target ($Al_2O_3\;2%$) respectively. The intermediate condition with optimum transmittance and conductivity was obtained by controlling the sputtering parameters. Oxygen gas ratio for this condition was $0.5{\times}10^{-2}~1.0{\times}10^{-2}$ in oxide target and. In case of metal target, this optimum oxygen gas ratio at the applied power of 0.6 kW and 1.0 kW was 0.215~0.227 and 0.305~0.315, respectively. The resistivity of AZO film deposited was obtained $1.2~1.4{\times}10^{-3} {\Omega}{\cdot}$cm as deposited state regardless of target species.

• Journal of the Korean Chemical Society
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• v.44 no.5
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• pp.403-409
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• 2000

The formation and dissociation rates of $Zn^{2+}$ Complexes with l,4,7,10-tetraaza-13,16-diox-acyclooctadecane-N,N',N",N'"-tetraacetic acid (1), 1,4,7,10-tetraaza-13,16- dioxacyclooctadecane-N,N',N",N'"-tetramethylacetic acid (2), and 1,4,7,10-tetraaza-13,16- dioxacyclooctadecane-N,N',N",N'"-tetrapropionic acid(3) have been measured by stopped-flow and conventional spectrophotometry. Observations were made at 25.0$\pm$0.1 $^{\circ}C$ and at an ionic strength of 0.10 M NaClO$_4$. The formation reactions of $Zn^{2+}$ ion with 1 and 2 took place by the rapid formation of an intermediate complex (ZnH$_3L^+$) in which the $Zn^{2+}$ ion is incompletely coor-dinated. This might then lead to be a final product in the rate-determining step.ln the pH range 4.76-5.76, the diprotonated (H2L2-) form is the kinetically active species despite of its low concentration. The stability con-stants (log$K_{(ZnH$_3$3$L^+$)}$) and specific water-assisted rate constants (koH) of intermediate complexes have been deter-mined from the kinetic data. The dissociation reactions of $Zn^{2+}$ complexes of 1,2, and 3 were investigated with $Cu^{2+}$ ions as a scavenger in acetate buffer. All complexes exhibit acid-independent and acid-catalyzed con-tributions. The effect of buffer and $Cu^{2+}$ concentration on the dissociation rate has also been investigated. The ligand effect on t dissociation rate of $Zn^{2+}$ complexes is discussed in terms of the side-pendant armsand the chelate ring sizes of the ligands.

• The Korean Journal of Ecology
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• v.6 no.4
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• pp.257-260
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• 1983

The concentration of heavy metals in 12 eggs collected from 6 nests of Intermediate Egret, Egretta intermedia intermedia from Ogjong-myun, Hadong-gun, Kyungnam, was examined by atomic absorption spectrophoto-meter method in 1983. It was found that heavy metals are contained in their eggs with highest concentration Cd and Cu in the eggshell and Cr, Zn, Pb and Mn in the yolk, respectively. The thin-shelled group, by their eggshell thickness grouping, contained heavy metal in higher amount than that of thick eggshelled group. And the thin group showed small values in weight of individual egg, its yolk and albumen.