• Journal of the Korean Ceramic Society
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• v.51 no.6
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• pp.612-617
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• 2014

The microstructure, nonlinear properties, and impulse clamping characteristics of Pr/Co/Cr/Al co-doped zinc oxide ceramics were investigated with various contents of $Er_2O_3$. Increasing $Er_2O_3$ content increased the density of the sintered pellets from 5.69 to $5.83g/cm^3$, and decreased the average grain size from 10.6 to $6.5{\mu}m$. With increased $Er_2O_3$ content, the breakdown field increased from 2318 to 4205 V/cm, and the nonlinear coefficient increased from 19.4 to 40.2. The clamp characteristics were improved with the increase of the content of $Er_2O_3$. The varistors doped with 2.0 mol% exhibited the best clamp characteristics, in which the clamp voltage ratio was 1.40-1.73 at 1-50 A in an impulse current.

• Transactions on Electrical and Electronic Materials
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• v.7 no.4
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• pp.189-195
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• 2006

The microstructure, electrical and dielectric properties, and stability against DC accelerated aging stress of the varistors, which are composed of quaternary system $ZnO-Pr_6O_{11}CoO-Cr_2O_3-based$ ceramics, were investigated for different $La_2O_3$ contents. The increase of $La_2O_3$ content led to more densified ceramics, whereas abruptly decreased the nonlinear properties by incorporating beyond 1.0mol%. The highest nonlinearity was obtained from 0.5mol% $La_2O_3$, with the nonlinear coefficient of 81.6 and the leakage current of $0.1{\mu}A$. The varistors doped with 0.5mol% $La_2O_3$ exhibited high stability, in which the variation rates of breakdown voltage, nonlinear coefficient, leakage current, dielectric constant, and dissipation factor were -1.1%, -3.7%, +100%, +1.4%, and +8.2%, respectively, for stressing state of $0.95V_{1mA}/150^{\circ}C/24h$.

• Bulletin of the Korean Chemical Society
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• v.16 no.2
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• pp.120-125
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• 1995

Solid solutions of Pr2-xBaxNiO4±δ with K2NiF4-type structure were prepared in air and characterized by powder X-ray diffraction, Rietveld refinements, iodometry titrations, and conductivity measurements. The range of the solid solution was 0 ≤ x < 0.5. The crystal structure changes from orthorhombic (Fmmm) for x ≤ 0.1 to pseudo-tetragonal (I4/mmm) for x ≥ 0.2. The orthorhombic structure of x=0.1 transforms to tetragonal at low temperature. The bond distances obtained from the Rietvel analyses did not vary significantly with the Ba content except that of Ni-O (parallel to the c-axis) which showed an abrupt increase from x=0.1 to 0.2. The excess oxygen content (δ) decreases from 0.241 to 0.03 with increasing substituted Ba contents within the solution range. The samples are all semiconductors at the temperature range 4 < T < 300 K.

• Korean Journal of Microbiology
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• v.38 no.3
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• pp.213-220
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• 2002

Inducible expression system for the three structural proteins, capsid (C), precursor membrane (prM/M), and envelop (E) of Japanese encephalitis virus (JEV) was established in BHK-21 cells. Doxycycline, a tetracycline analog, was utilized as an inducer. Transfectants BHK-21/IV (vector only), BHK-21/IC (for C), BHK-21/IP3 (for prM), and BHK-21/IE1 (for E) were selected and cloned in the presence of G4l8 or hygromycin. Transcribed mRNAs for the corresponding genes were observed after doxycycline induction. Effects by the JEV structural gene expression on the transfectants were monitored via cell growth, chromatin condensation, internucleosomal DNA fragmentation, and DNA contents analyses. Clear cell growth retardation and chromatin condensation were observed in all three transfectants while only BHK-2/IC corresponded to the induction status in the DNA fragmentation and DNA content analyses. Combined results, therefore, suggested that JEV capsid protein should be one of the direct and independent factors in apoptotic cell death induced by IEV infection.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.103-116
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• 2008

In this study, in-situ testing method, Dynamic Cone Penetration Test(DCPT) was presented to establish a new compaction control criteria with using mechanical property like elastic modulus instead of unit weight for field compaction control. Soil chamber tests and in-situ tests were carried out to confirm DCPT tests can predict the designed elastic modulus after field compaction, and correlation analysis among the DCPT, CBR and resilient modulus of sub grade were performed. Also, DCPT test spacing criteria in the construction site was proposed from the literature review. In the result of laboratory tests, Livneh's equation was the best in correlation between PR of DCPT and CBR, George and Pradesh's equation was the best in the predicted resilient modulus. In the resilient modulus using FWD, Gudishala's equation estimates little larger than predicted resilient modulus and Chen's equation estimates little smaller. And KICT's equation estimates the modulus smaller than predicted resilient modulus. But using the results of laboratory resilient modulus tests considering the deviatoric and confining stress from the moving vehicle, the KICT's equation was the best. In the results of In-situ DCPT tests, the variation of PR can occur according to size distribution of penetrate points. So DCPT test spacing was proposed to reduce the difference of PR. Also it was shows that average PR was different according to subgrade materials although the subgrade was satisfied the degree of compaction. Especially large sized materials show smaller PR, and it is also found that field water contents have influence a lot of degree of compaction but a little on the average PR of the DCPT tests.

• Journal of Bio-Environment Control
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• v.14 no.3
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• pp.182-189
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• 2005

This research was conducted to determine physical properties of four root media, peatmoss + vermiculite (1:1, v/v; PV), peatmoss + composted rice hall (1:1, PR), peatmoss + composted saw-dust (1:1 : PS) and peatmoss + composted pine bark (1:1 PB), as influenced by incorporation rate of Stock-sorb C (STSB). Each root medium containing STSB was packed in 22 cm diameter plastic pot and the physical properties were determined at 5 weeks after packing. As incorporation rate of STSB were elevated, total porosity increased in PV, PS and PB media with statistical differences at $5{\%}$ level. Those also resulted in increase of container capacity in PS and PB media, but statistical differences were not observed in PV and PR media. Elevated incorporation rate of STSB in PV, PS and PB media resulted in increase of air space with statistical differences. Trends in air space of the three root media showed a linear as well as quadratic responses to STSB contents of media. As incorporation rate of STSB increased, more water was retained in four root media at the soil moisture tension of 4.90 kPa, 9.81 kPa, 29.4 kPa and 1.5 MPa. The amount of water retained in PS medium was the highest at the moisture tension at 29.4 kPa and 1.5 MPa followed by PB, PR and PV medium. These results indicated that elevation of incorporation rate of STSB to various root media increased moisture retention capacity, but did not increase the available water holding capacity.

• Korean Journal of Materials Research
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• v.9 no.5
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• pp.484-490
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• 1999

$(Pb,La)TiO_3$(PLT) thin films were prepared on Pt/SiO$_2$/Si substrates by the sol-gel method and investigated the crystalline and electrical properties according to La concentration and post-annealing temperatures. The PLT films annealed at above $600^{\circ}C$ were exhibited the typical perovskite structures regardless of La contents. When the $(Pb,La)TiO_3$(PT) films were doped with La concentration up to 10mol%(PLT-10), the degree of z-axis orientation was greatly decreased from 63% to 26%. From AES depth profiles for the PLT-10 samples, no remarkable inter-reaction between PLT film and lower Pt electrode was found. The remanent polarization$(2Pr,Pr_+-Pr_-)$ were increased from $4\muC\textrm{cm}^2 to 16\muC\textrm{cm}^2$ as the annealing temperature increased from $600^{\circ}C to 700^{\circ}C$. This result may be ascribed to the improvement of crystallinity by the high temperature post-annealing. The dielectric constant$({\varepsilon}r)$ and tangent loss(tan$\delta$) of the PLT-10 films annealed at $650^{\circ}C$ were about 193 and 0.02, respectively with the pyroelectric coefficient($\gamma$) of around $4.0nC/\textrm{cm}^2{\cdot}^{\circ}C at 30^{\circ}C$.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.69-75
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• 2019

The purpose of this study was to examine the effects of age and gender on Eastern and Western cultural values imbedded in online advertising. This study conducted a survey of 180 men and women ages between 10s and 60s who lived in Seoul, Korea. They responded the acceptance degree of six online advertising emphasized three Korean traditional values and three Modern values. Research hypotheses of this study were the acceptance of cultural values in online advertising is different between ages, but similar between gender. The hypotheses were supported as the previous studies. Findings suggest several theoretical and practical implications that convergence between modern and traditional values is a more important variable to study in the research of online advertising.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.3
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• pp.223-227
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• 2007

The effect of Eu contents on the ferroelectric properties of $Bi_{4-x}Eu_xTi_3 O_{12}$ (BET) thin films has been investigated. Bismuth Europium titanate thin films with a Eu contents were prepared on the $Pt/Ti/SiO_2/Si$ substrate by metal-organic decomposition technique. The structure and the morphology of the films were analyzed using X-ray diffraction (XRD) and field emission scanning microscopy (FE-SEM), respectively. From the XRD analysis, it was found that BET thin films have polycrystalline structure, and the layered-perovskite phase is obtained when the Eu contents exceeds 0.2 (x > 0.2). Also, the ferroelectric characteristics of the BET thin films were found to be dependent on the Eu content. Particularly, the BET films doped with x = 0.75 show better ferroelectric properties (remanent polarization 2Pr = 60.99 C/$cm^2$ and only a little polarization fatigue up to $3.5{\times}10^9$ bipolar switching cycling) than those doped with other Eu contents.

• Journal of Digital Contents Society
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• v.18 no.5
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• pp.831-837
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• 2017

The popularization of smart phones is increasing interest in individual customized service and various systems have been changing in order to meet such changes to satisfy facilities such as museums. Museum has the element of view, contained purpose of history education, also has role as institution that should have fun and education. In order to achieve this purpose, it is necessary to arouse sufficient interest in cultural assets, In parallel, to provide various contents of cultural assets is essential. Therefore, to provide an efficient viewing cultural assets services in this study make a study to effective method for combined education and evaluation using Unity3D engine and SDK for Vuforia called Augmented Reality development.