• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.1
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• pp.115-131
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• 1996

The PVT(pressure-volume-temperature) relation of main-chain dimer liquid crystals having structures such as $\alpha$,$\omega$-bis[(4,4`-cyanobiphenyl) oxy] alkane(CBA-n with=9, 10) were studied. these dimer liquid crystals are known to form an enantiotropic nematic mesophase. In this work, we have determined the volume change as a function of temperature and pressure by using a GNOMIX PVT apparatus. In the V-Tcurves obtaind from isobaris mearements on various pressures, volume changes were observed at the nematic-isotropiz and nematic-crystal phase transitions. The volume changes at the transition exhibit slight odd-even effect with respect to the number of methylene unit n. The values of the (S)v obtained at the NI transition for CBA-9 and -10 were 6.9 and 12.6J/mol k. The valuesof (S)v for the CN transition were estimated on the basis of DSC(differential scanning calorimetry) data: 58.8(CBA-9) and 65.3J/mol k (CBA-10). For both transition, it was found that the correction about the volume change is significant, ranging from 40% to 60% of the total transition entropy observed under constant pressure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.157-160
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• 2001

Three sets of ZnO ceramic devices (reference samples with Matsuoka\`s composition; added 7o MgO, A1$_2$O$_3$, SiO$_2$) have been prepared by the conventional mixed oxide route. These additives were determined by the factors of valences and ionic radiuses. DC accelerated degradation test was performed for analysis of degradation characteristics versus the various additives. The conditions of DC degradation test were 115${\pm}$2$^{\circ}C$ for 12h. Using XRD and SEM, the Phase and microstructure of samples were analyzed respectively. E-J analysis was used to determine ${\alpha}$. Frequency analysis was accomplished to understand the relationship between R$\sub$g/ and $R_{b}$ with the electric stress at the equivalent circuit.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.297-300
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• 1997

In this study, The PVDF thin film was fabricated on the one method of dry-process the physical vapor deposition method, applied electric field, and evaporation control in $\beta$-PVDF thin film preparation. A study on the electric-field-phase change of PVDF thin film in physical vapor deposition using the polymer deposition apparatus which are manufactured for oneself. In the analysis of Fourier-Transform Infrared spectra, according to increasing of electric field intensity, the 510$cm^{-1}$ / peak and 1273$cm^{-1}$ / peak which are showed in $\beta$-PVDF increase, on the contrary the 530$cm^{-1}$ / peak and 977$cm^{-1}$ / peak which are showed in $\alpha$-PVDF decrease.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.427-430
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• 2001

The degradation characteristics versus MgO Additive for the ZnO ceramic devices fabricated by the standard ceramic techniques is investigated in this study. It were made these devices be basic Matsuoka's composition. Especially, MgO were added to analyze the degradation characteristics and sintered in air at 1300$^{\circ}C$. The conditions of DC degradation test were 115${\pm}$2$^{\circ}C$ for 12h. Using XRD and SEM, the phase and microstructure of samples were analyzed respectively. The elemental analysis in the microstructures was used by EDS, E-J analysis was used to determine ${\alpha}$ . Frequency analysis was accomplished to understand the relationship between R$\sub$g/ and $R_{b}$ with the electric stress at the equivalent circuit.

• Journal of Welding and Joining
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• v.19 no.5
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• pp.506-511
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• 2001

Weld overlay has been developed to improve the property of material surface which is used in the severe environment. Weld overlay is the process which uses an arc heat and welds different composition of alloy on the substrate for the improvements of heat resistance and wear resistance. Weld overlay has a lot of advantages which are high hardness, good processing efficiency, easy controlling of layer thickness, good quality and low cost. In this study, weld overlay was performed by MAG welding on the base metal(SS400) with filler metal which contain composite powders(Cr+C+Mn+Mo+NbC) and solid wire(JIS-YGW11). Characterization of hardness and wear resistance were analyzed by EDS, EPMA, XRD and observations of microstructure were performed to investigate characteristics of overlays. The experimental results of overlaid specimens manufactured with Cr+C+Mn+Mo+NbC powders were obtained as fellows. ${\alpha}-phase$, M(Fe, Cr)3C and NbC of overlays were increased with decreasing the wire feed rates and increasing powder feed rates. Also the hardness of overlays were increased and the specific wear were decreased.

• Korean Journal of Plant Resources
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• v.1 no.1
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• pp.80-87
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• 1988

Hybries which was made up by chromosome of L. longiflorum and L. x elegans, using root-tip individual which was obtained through ovary slice culture, and root-tip of these parents, with hoirugen staining, gimsa staining and Q-H staining inaccordance with the location and the existence of secondary construction which waslocating near short arm centromere of No, 1,2,6,9. In metaphase of meiosis ofhybrid which was made up by univalent from 2 individuals to 10 individuals wasobserved, and nuclear plate which was having abnormal type's synthesis amounted to91% of all cells whieh were observed. This result showed the fact that someobstacle arose annormal progress of the divission after that time. 63% of the cellshad micronucleus from 1 individlial to 4 individuals in tetrad phase of meiosisdivision. The peroxidase and $\alpha$ -estelase zymogram phenotypes of parents andhybrids were determined using agarlose IEF gel. Crosses were performed betweenparents bearing dissimilar allelomorphs in orther to discern the genetic control ofthe resolved enzymes. Genetic variation of hybrids were detected at all but 2 plant progenies.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.51.2-51.2
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• 2012

Red Active Galactic Nuclei (AGNs) are suspected to intermediate stage between ULIRG and AGN phase. As well as, red AGNs are suspected to have more than 50% of whole AGN population. For understanding the characteristics of red AGN, Black Hole (BH) mass is a key property and can not be estimated by existed method such as reverberation mapping and single epoch method using 5100A continuum and Balmer lines. Thus we still don't know their characteristics and properties in clearly. To estimate properties of red AGNs without the effect of dust extinction, we obtained Near InfraRed (NIR) spectra of 31 reverberation mapped AGNs and 49 Palomar-Green(PG) Quasi-Stellar Objects (QSOs) by using the infrared camera (IRC) of AKARI space telescope with unique wavelength range 2.5-5.0 ${\mu}m$. Upon this spectra, we measured the FWHM and luminosity of Brackett ${\alpha}$ and ${\beta}$ lines for deriving new BH mass estimators of AGNs.

• Journal of Korea Foundry Society
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• v.12 no.2
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• pp.139-148
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• 1992

The mechanical properties of Ti-Al intermetallic compounds which contain Mn, Zr, or Cr as the third element have been evaluated by means of hardness and compression tests. Microstructures have also been examined using an optical microscope. The cast structures of Ti-Al alloys are coarsened and the lamellar volume fraction is increased by the additions of Mn or V, but the cast structures are refined by the addition of Zr. Hardness tests of room temperature and compression tests at $600^{\circ}C$ showed that the mechanical properties of Ti-Al alloys were mainly dependent on the volume fraction of the ${\alpha}_2$ phase, grain size and solid solution hardening. However according to the compression test at $1000^{\circ}C$, the yield strength of Ti-Al alloys decreased with an increase in Mn or Cr content, but increased with an increase in the Zr content.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.4
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• pp.738-746
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• 1988

Fatigue crack propagation of duplex stainless steel weldments was studied to develop further phenomenological understanding of the influences of welding heat cycle accompanying microstructural changes. Fatigue tests were carried out under constant amplitude of load in air at room temperature. The results showed that the crack propagation rate was different in base metal, heat affected zone and welding line. The crack propagation behavior in each part of duplex stainless steel was strongly dependent on phase ratio(.gamma../.alpha.) and several factors of microstructure also affected this propagation behavior. The fractographic feature in each part of steel were discussed on crack propagation behaviors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.418-421
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• 2003

Specimens of Ti-10Ta-10Nb have been hot upset forged after heating to either the $\alpha$+$\beta$ and $\beta$-phase field. The variety temperatures (At 650, 700, 750, 800, 85$0^{\circ}C$) and strain rates (At 0.001, 0.01. 0.1, 1, 10 $s^{-1}$ ) were used. On the basis of flow stress data obtained as a function of temperature and strain rate in compression, a processing map for hot working has been developed. At strain rates lower than about 0.1 $s^{-1}$ and almost temperatures, processing efficiency exhibited high, but at 0.001 $s^{-l}$, and temperature 80$0^{\circ}C$, low because the Shear band has occurred. On the basis of the processing map, the optimum processing routes available for hot working of this material are outlined.d.