• Journal of the Korean Ceramic Society
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• v.26 no.3
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• pp.423-437
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• 1989

Al2O3/ZrO2 composites were prepared by precipitation method using Al2(SO4)3.18H2O, ZrOCl2.8H2O and YCl3.6H2O as starting materials and NH4OH as a precipitation agent. Al2O3/ZrO2 composites(series A) were prepared by mixing Al2O3 powder obtained by single precipitation method with ZrO2(＋3m/o Y2O3) powder obtained by co-predipitation method. Al2O3/ZrO2 composites (series B) were prepared by co-precipitation method using the three starting materials. In all cases, the composition was controlled as Al2O3-15v/o ZrO2(＋3m/o Y2O3). The composites of series A showed higher final relative densities than those of series B and tetagonal ZrO2 in all cases was retained to about 95% at room temperature. ZrO2 particles were coalesced more rapidly in grain boundary of Al2O3 than within Al2O3 grain. ZrO2 particles were located at 3-and 4-grain junction of Al2O3 and limited the grain growth of Al2O3. It was observed that MgO contributed to densification of Al2O3 but limited grain growth of Al2O3 by MgO was not remarkable. In all Al2O3/ZrO2 composites, exaggerated grain growth of Al2O3 was not observed and Al2O3/ZrO2 composites were found to have homogeneous microstructures.

• Journal of Information Technology Services
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• v.20 no.2
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• pp.13-31
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• 2021

Recently, delivery app services based on the O2O platform are increasing rapidly. Accordingly, various studies on O2O service have been conducted. Most of the studies are on consumer behavior in O2O services, and few studies on platform vendors have been conducted. Therefore, this study empirically analyzed the factors affecting the vender's intention to continuous use in the O2O delivery app platform service. Based on prior researches, we set the quality characteristics and network characteristics of the O2O platform as independent variables. The quality characteristics of the O2O platform consisted of system quality, information quality, and service quality, and the O2O platform network characteristics consisted of network externality and platform reputation. Perceived value and switching cost were set as mediated variables, and vender's intention to continuous use was set as dependent variables. For empirical analysis, we conducted a survey targeting vendors of O2O delivery app platform service, and conducted frequency analysis, factor analysis, reliability analysis, and regression analysis. As a result of the analysis, the quality characteristics of the O2O platform, such as system quality, information quality, service quality, and O2O platform network characteristics, showed that network externality and platform reputation had a positive effect on perceived value. The perceived value was found to have a positive effect on the switching cost and the intention to continuous use, and the switching cost was found to mediate the perceived value and the intention to continuous use. This study can contribute to the establishment of platform operation strategy as an empirical analysis on the factors that influence the intention of O2O platform vendors to use the platform continuously.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.108-109
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• 2006

ZnO semiconductor has a wide band gap of 3.37 eV and a large exciton binding energy of 60 meV, and displays excellent sensing and optical properties. In particular, ZnO based 1D nanowires and nanorods have received intensive attention because of their potential applications in various fields. We grew ZnO buffer layers prior to the growth of ZnO nanorods for the fabrication of the vertically well-aligned ZnO nanorods without any catalysts. The ZnO nanorods were grown on Si (111) substrates by vertical MOCVD. The ZnO buffer layers were grown with various thicknesses at $400^{\circ}C$ and their effect on the formation of ZnO nanorods at $300^{\circ}C$ was evaluated by FESEM, XRD, and PL. The synthesized ZnO nanorods on the ZnO film show a high quality, a large-scale uniformity, and a vertical alignment along the [0001]ZnO compared to those on the Si substrates showing the randomly inclined ZnO nanorods. For sample using ZnO buffer layer, 1D ZnO nanorods with diameters of 150-200 nm were successively fabricated at very low growth temperature, while for sample without ZnO buffer the ZnO films with rough surface were grown.

• Journal of Korean Medicine Rehabilitation
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• v.18 no.2
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• pp.97-109
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• 2008

Objectives : Effects of Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) on intellectual development and learning ability were investigated growth and intellectual impairment rat with insufficient nutrition diet. Methods : We divided male Sprague-Dawley rats into 4 groups(A, B, C, D). They were normal group(A), growth deficiency rat with insufficient nutrition diet group(B), growth deficiency rat with 0.1% Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) group(C) and growth deficiency rat with 0.2% Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) group(D). They were administered for 5 weeks. We measured body weight, serum growth hormone, insulin-like growth factor and thyroid stimulating hormone, RBC, concentration of Hb and PCV ratio, total WBC and its composition, the values of plasma glutamic oxaloacetic transaminase(GOT) and glutamic pyruvic transaminase(GPT) activities and morris water maze test in escape distance, escape time and escape speed. Results : 1. Body weight showed a tendency to increase in the Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups and 0.2% Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) group showed significantly different than control groups. 2. Serum growth hormone, insulin-like growth factor and thyroid stimulating hormone showed a tendency to increase in Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups, however these values showed no significantly different. 3. About the counts of RBC, 0.1% and 0.2% Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups showed significantly different than control groups. Concentration of Hb was higher than control group in Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups. And 0.2% Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) group showed significantly different than control groups in PCV ratio. 4. The counts of total WBC and its composition showed no significantly different in all treatment groups. 5. The values of plasma glutamic oxaloacetic transaminase(GOT) and glutamic pyruvic transaminase(GPT) activities showed no significantly different in all treatment groups. 6. In the morris water maze test, in escape distance and escape speed, Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups showed no significantly different than control group. But Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups showed the increasing tendency. Conclusions : So Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) have an effect of promoting growth of rats and might be effect to treat various kinds of growth delay in children.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.190-195
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• 2000

The electrical properties and stability of ZPCE varistors consisted of $ZnO-Pr_6O_{11}-CoO-Er_2O_3$ ceramics were investigated. $ZnO-Pr_6O_{11}-CoO-Er_2O_3$ based ceramics were sintered at $1300^{\circ}C$ and $1350^{\circ}C$, respectively, without and with 0.5 mol% $Er_2O_3$. The varistors sintered at $1300^{\circ}C$ exhibited a better nonlinearity than that $1350^{\circ}C$. The varistors with $Er_2O_3$ of 0.5 mol% exhibited a high nonlinear exponent of 52.8. However, they easily degraded due to the low density below 85% of TD. On the other hand, the varistors sintered at $1350^{\circ}C$ without $Er_2O_3$ exhibited an extremely poor nonlinearity, but the varistors with $Er_2O_3$ of 0.5 mol% exhibited a relatively good nonlinearity, which the nonlinear exponent is 34.8 and the leakage current is $7.4\;{\mu}A$ Morever, they exhibited a very high stability, which the variation rate of varistor voltage, nonlinear exponent, and leakage current are -0.9%, -2.9%, and +2.7%, respectively, under the third stress $(0.80 V_{1mA}/90^{\circ}C/12h)$ + $(0.85 V_{1mA}/115^{\circ}C/12h)$ + $(0.90 V_{1mA}/120^{\circ}C/12h)$. Consequently, it was estimated that $ZnO-Pr_6O_{11}-CoO-Er_2O_3$ ceramics will be usefully applied to develop the advanced $Pr_6O_{11}$-based ZnO varistors.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.196-196
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• 2011

Molecular $N_2O$ has bee known to react over oxygen vacancy on a reduced rutile $TiO_2$(110)-1${\times}$1 surface to desorb as molecular $N_2$ leaving oxygen atom behind. In the present study, we investigated the reaction of $N_2O$ on rutile $TiO_2$(110) using temperature-programmed desorption (TPD). Our results indicate that $N_2O$ does not react over the oxygen vacancy under a typical UHV experimental condition. On a rutile $TiO_2$(110)-1${\times}$1 with a well-defined oxygen vacancy concentration of 5% ($2.6{\times}10^{13}/cm^2$), $N_2O$ desorption features show a monolayer peak maximum at 135 K followed by a small peak maximum at 170 K. When the oxygen vacancy is blocked with $H_2O$, the $N_2O$ peak at 170 K disappears completely, indicating that the peak is due to molecular $N_2O$ interacting with oxygen vacancy. The integrated amount of desorbed $N_2O$ plotted against the amount of adsorbed $N_2O$ however shows a straight line with no offset indicating no loss of $N_2O$ during our cycles of TPD measurements. In addition, our $N_2O$ uptake measurements at 70~100 K showed no $N_2$ (as a reaction product) desorption except contaminant $N_2$. Also, $H_2O$ TPD taken after $N_2O$ scattering up to 350 K indicates no change in the vacancy-related $H_2O$ desorption peak at 500 K showing no change in the oxygen vacancy concentration after the interaction with $N_2O$.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.247-261
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• 2017

O2O service that combine online with offline service has been rapidly increasing and O2O service is the new trend that merges online commerce with traditional markets in various fields. The purpose of this study is to investigate influences of University Student's Perceived O2O application characteristics on O2O services satisfaction and continuous use intention. For this purpose, questionnaires including O2O application characteristics scale, customer perceived O2O satisfaction scale and O2O use intention scale were administered to 241 college students in Seoul. Regression analysis revealed that O2O application Characteristics showed influences of O2O service satisfaction. The O2O application charac*teristics showed influences of continuous use of intention of O2O services, O2O services satisfaction showed partial influence continuous use intention of O2O service. The result of this study is expected to provide implication as an initial study O2O service which is spreading with the growth of mobile ICT. Ultimately, the results of this study provide a number of theoretical and practical implications.

• ETRI Journal
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• v.37 no.6
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• pp.1135-1142
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• 2015

Multilayered ZnO-$SnO_2$ heterostructure thin films consisting of ZnO and $SnO_2$ layers are produced by alternating the pulsed laser ablation of ZnO and $SnO_2$ targets, and their structural and field-effect electronic transport properties are investigated as a function of the thickness of the ZnO and $SnO_2$ layers. The performance parameters of amorphous multilayered ZnO-$SnO_2$ heterostructure thin-film transistors (TFTs) are highly dependent on the thickness of the ZnO and $SnO_2$ layers. A highest electron mobility of $43cm^2/V{\cdot}s$, a low subthreshold swing of a 0.22 V/dec, a threshold voltage of 1 V, and a high drain current on-to-off ratio of $10^{10}$ are obtained for the amorphous multilayered ZnO(1.5nm)-$SnO_2$(1.5 nm) heterostructure TFTs, which is adequate for the operation of next-generation microelectronic devices. These results are presumed to be due to the unique electronic structure of amorphous multilayered ZnO-$SnO_2$ heterostructure film consisting of ZnO, $SnO_2$, and ZnO-$SnO_2$ interface layers.

• Journal of the Korean Ceramic Society
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• v.40 no.5
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• pp.447-454
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• 2003

Samples were prepared by the solid-state reaction method. The nominal composition of the samples was B $i_{1.84}$P $b_{0.34}$S $r_{1.91}$C $a_{2.03}$C $u_{3.06}$ $O_{10+{delta}$ prepared from powder of B $i_2$ $O_3$, PbO, SrC $O_3$, CaC $O_3$, and CuO. They were pulverized, mixed with AgO, A $u_2$ $O_3$and MgO of 50 wt%. Finally, they were sintered at 820 to 85$0^{\circ}C$ in air. The structural characteristics, the microstructure of surface and the critical temperature with respect to the each samples were analyzed by XRD, $T_{c}$, SEM and EDS respectively. It was found that the the critical temperature of the silver oxide additive samples (99.58 K) is higher than those of gold or magnesium oxides additive samples, but all those values are lower than that of pure Bi-2223 phase. The microstructure of surface showed the tendency which the AgO additive samples become more minuteness than A $u_2$ $O_3$ and MgO additive samples.s.samples.s.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.383-386
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• 1999

The importance of rechargeable lithium cells has been emphasized. So a large variety of materials has been discovered and evaluated for use as reversible cathodes and electroyltes. This paper examines the charge/discharge properties and the charge/discharge cycling life of Li$_2$O-P$_2$O-V$_2$O$_{5}$Li cells. In audition, DTA tests were carried out on Li$_2$O-P$_2$O-V$_2$O$_{5}$ glass. As a result the best performance was achieved when 0.3Li$_2$O-0.1P$_2$O$_{5}$-0.6V$_2$O$_{5}$Li cells was mixed with SP270. that is discharge capacity of 240mAh/g have been achieved. In addition this battery exhibited good cycling performance. Considering these results we expected utilization of the Li$_2$O-P$_2$O-V$_2$O$_{5}$ glass as a cathode material in a secondary battery.y battery.