• KSBB Journal
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• v.7 no.3
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• pp.191-200
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• 1992

Several strains of Agrobacterium tumefaciens were isolated from soil in the Taegu area and characterized to develop some useful vector systems for higher plant genetic engineering. The selected colonies had a unique form, and strains from the colonies were capable of tumor formation on the sunflower leaf surface. They had a large plasmid. The restriction analysis showed that they were another kinds of Ti plasmic compared with C58 and Ach5. The isolated strains were identified as the nopaline type and also as biovar 1 A. tumefaciens, according to their tumor morphology, blophyslcal and biochemical characteristics. One of the isolated strains, AK204 was transformed with binary vector (pGA642), having selectable marker (Kmr, Tcr). Furthermore, maize tissue cells were transformed by cocultivation with AK204/pGA642, and the transformants were selected on the selective medium and identified using PAGE patterns of their soluble proteins.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.08a
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• pp.85-88
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• 2003

$Sr_xBa_{1-x}Nb_2O_6$(SBN, $025{\leq}x{\leq}0.75$) ceramic is a ferroelectric material with tetragonal tungsten bronze (TTB) type structure, which has a high pyroelectric coefficient and a nonlinear electro-optic coefficient value. In spite of its advantages, SBN has not been investigated well compared to other ferroelectric materials with perovskite structure. In this study, SBN thin film was manufactured by ion beam sputtering technique using the prepared SBN target in Ar/$O_2$ atmosphere. SBN30 thin film of 500 ${\AA}$ was pre-deposited as a seed layer on Pt(l00)/$TiO_2$/$SiO_2$/Si substrate followed by SBN60 deposition up to 4500 ${\AA}$ in thickness. SBN60/SBN30 layer was deposited at different Oxygen amount of 0, 8.1, 17, and 31.8 sccm, respectively. The crystallinity and orientation behavior as well as electric properties of SBN60/SBN30 multi-layer were examined. The deposited layer was uniform and the orientation was shown primarily along (001) plane from XRD pattern. The crystal structure and the electric properties depended on the Oxygen amount, heating temperature and was the best at O2 = 8.1 seem, $750^{\circ}C$. In electric properties of Pt/SBN60/SBN30/Pt thin film capacitor prepared, the remnant polarization (2Pr) value was 13 ${\mu}C/cm^2$, the coercive field (Ec) 75 kV/cm, and the dielectric constant 1492, respectively.

• Journal of Biomedical Engineering Research
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• v.6 no.1
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• pp.37-46
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• 1985

Development of a dental Ni-Cr alloy system for porcelain veneering crown and bridge was studied in this research. The principles of alloy design were a) It should not contain toxic beryllium. b) It should have low melting Point. c) It should be easily ground and polished. d) It should possess an adequate strength to resist the deformational force In the mouth. e) It should be bondable Ivith porcelain by chemically. After investigating the effect of minor elements such as boron and rare earth metals on the mechanical properties of the Ni-Cr alloy system, the compromised ideal composition for dental use was determined. The composition was l9.6%, Cr, 5.6% Mo, 3.4% Si, 1, 0% Fe, 0.01% Ti, 0.5-1.0% B, 0.2-0.6% misch metal, balance Ni. To compare the performance of experimental alloy with commercially available alloys, the properties such as strength, melting point, and bond strength were measured. The results Ivere as follows: a) Boron increases the strength of the alloy but reduces the elongation. b) Misch metal increases the strength when the boron content is low, but does not increase the strength when boron content is high. And it reduces the elongation drastically, c) Mechanical strength of the experimental alloy was not superior to commercially available Be containing alloy, but handling performance such as castability, ease of granting and polishing, and cuttability were superior to the Be containing alloy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.271-274
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• 2003

[ $Sr_xBa_{1-x}Nb_2O_6$ ] (SBN, $0.25{\leq}x{\leq}0.75$) ceramic is a ferroelectric material with tetragonal tungsten bronze (TTB) type structure, which has a high pyroelectric coefficient and a nonlinear electro-optic coefficient value. In spite of its advantages, SBN has not been investigated well compared to other ferroelectric materials with perovskite structure. In this study, SBN thin film was manufactured by ion beam sputtering technique using the prepared SBN target in $Ar/O_2$ atmosphere. SBN30 thin films of different thickness were pre-deposited as a seed layer on $Pt(100)/TiO_2/SiO_2/Si$ substrate followed by SBN60 deposition up to $4500\;{\AA}$ in thickness. As-deposited SBN60/SBN30 layer was heat-treated at different temperatures of 650, 700, 750, and $800\;^{\circ}C$ in air, respectively, The crystallinity and orientation behavior as well as electric properties of SBN60/SBN30 multi-layer were examined. The deposited layer was uniform and the orientation was shown primarily along (001) plane from XRD pattern. There was difference in the crystal structure with heat-treatment temperature, and the electric properties depended on the heating temperature and the seed-layer thickness. In electric properties of Pt/SBN60/SBN30/Pt thin film capacitor prepared, the remnant polarization (2Pr) value was $15\;{\mu}C/cm^2$, the coercive field (Ec) 65 kV/cm, and the dielectric constant 1492, respectively.

• Research in Plant Disease
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• v.12 no.3
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• pp.205-212
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• 2006

Agrobacterium vitis is a causal agent of crown-gall disease on grapevine. Bacterial strains were isolated from crown galls of different grapevine varieties in grapevine farms of Kyungbuk(Kimcheon), Chungbuk(Okcheon), Chungnam(Daejon, Choenan) and Kyeonggi(Suwon, Ansung) areas in Korea from 2002 to 2005. Primer sets, Phe A and VirA, which were derived from pectate lysase gene and virA gene of Ti-plasmid in A. vitis were used to detect A. vitis strains from crown galls. PheA and VirA primers amplified DNA fragments of 0.25 kb and 0.5 kb from fifty-one bacterialstrains. They formed crown galls on grapevine variety, Kyoho, or carrot disks with variable pathgenecity It was confirmed that the biochemical characteristics of 10 bacterial strains that was strong pathogene city on grapevine were mostly in agreement with type culture strains of A. vitis, showing growth in the presence of 2% NaCl, non-production of acid from melezitose and negative response in production of 3-Ketolactose.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.118-121
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• 2007

Bulk metallic glass (BMG)/crystalline composites comprising a copper based BMG alloy and crystalline nickel were produced by means of eloctroless plating of nickel on $Cu_{54}Zr_{22}Ti_{18}Ni_6$ BMG powder and subsequent consolidation using spark plasma sintering. The plastic deformation behavior of BMG/crystalline composites was examined by uniaxial compression test at various temperatures in the supercooled liquid region (SLR) of the BMG alloy. The evolution of strain states during uniaxial compression was tackled by microstructure observations. Deformation temperature played an important role in the deformation behavior of BMG/crystalline composites, which was attributed to a strong temperature dependence of the flow stress of the BMG alloy in the SLR. BMG/crystalline composites deformed homogenously in the temperature range where the flow stress of the BMG alloy was close to that of crystalline nickel. In contrast, inhomogeneous deformation was observed in the temperature range where the flow stress of the BMG alloy largely differs from that of crystalline nickel.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.10
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• pp.35-42
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• 2002

Modulation frequency dependences of the pyroelectric properties of PLT (P $b_{1-x}$ L $a_{x}$ $Ti_{1-x}$ 4/ $O_3$) thin films with La concentrations of 5, 10 and 15㏖% have been investigated by using the dynamic method. The PLT thin film with 10㏖% of the La concentration (PLT(10) thin film) shows the most excellent pyroelectric properties among the films. For PLT(10) thin film, the pyroelectric coefficient shows the maximum value of 6.6$\times$10$^{-9}$ C/$\textrm{cm}^2$ㆍK without frequency dependence. The figure of merits for the voltage responsivity and specific detectivity are 1.03$\times$10$^{-11}$ Cㆍcm/J and 1.46$\times$10$^{-9}$ Cㆍcm/J, respectively. Voltage responsivity corresponding to the pyroelectric voltage is almost constant at low modulation frequency and decreases in proportional to frequency at high modulation frequency. Voltage responsivity is 5.15 V/W at 8Hz. Noise equivalent power (NEP) and specific detectivity ( $D^{*}$) of the PLT(10) thin film are 9.93$\times$10$^{-8}$ W/H $z^{1}$2/ and 1.81$\times$10$^{6}$ cmH $z^{1}$2/W at the frequency of 100Hz, respectively. The results indicate that PLT(10) thin film is very suitable for pyroelectric IR sensors.s.s.

• Journal of Sensor Science and Technology
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• v.23 no.4
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• pp.224-228
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• 2014

The electrocaloric effect of 9/65/35 PLZT thin film fabricated by the sol-gel method, which has not been studied yet, was investigated for its structural, electrical properties as well as temperature change property. The relaxor ferroelectric property of 9/65/35 PLZT thin film was confirmed by examining its dielectric and electrical properties. The relaxor property can cause a more pronounced electrocaloric effect (ECE) in a wider temperature range than normal ferroelectric film. To avoid errors caused by using an indirect measurement method, the leakage current generated by increasing temperatures was minimized by using the optimal maximum electric field ($350kVcm^{-1}$) in the thin film. The largest temperature change ${\delta}T$ (0.23 K) and the electrocaloric strength ${\xi}$ (0.68 mkcm/kV), calculated by equations were obtained. The maximum field change ${\delta}E$ ($191kVcm^{-1}$) was in the vicinity of the curie temperature ($200^{\circ}C$).

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.527-530
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• 2009

$(Ba_{0.57}Sr_{0.33}Ca_{0.10})TiO_3$(=BSCT) powders, prepared by the sol-gel method, were doped using $MnCO_3$ as the acceptor and $Dy_2O_3$ as the donor. This powder was mixed with an organic vehicle. BSCT thick films were fabricated by the screen-printing techniques on the alumina substrate. The structural and dielectric properties of BSCT thick films were investigated with variation of the $Dy_2O_3$ amount. As a result of the differential thermal analysis (DTA), the exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All the BSCT thick films showed the XRD patterns of a typical polycrystalline perovskite structure. The average grain size of BSCT thick films decreased with an increasing amount of $Dy_2O_3$. The relative dielectric constant and dielectric loss of the BSCT thick film doped $Dy_2O_3$ 0.1mol% were 4637.4 and 1.6% at 1kHz, respectively.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.3
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• pp.301-306
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• 2004

Statement of problem. Fibronectin mediates its biological effects by binding to integrins on cell membranes through a consensus site including the Arg-Gly-Asp (RGD) sequence within tenth type III module. Purpose. The purpose of our study was to investigate the adsorption affinity of human recombinant fibronectin peptide (hFNIII 9-10) to titanium and to investigate the effect of the surrounding ionic composition on the adsorption process. Material and methods. As for evaluating the affinity of hFNIII 9-10 to Ti, titanium disks were incubated in 40, 80 and $120{\mu}g/ml$ hFNIII 9-10 solution at $37^{\circ}C$ overnight, repectively. As for evaluating the effect of surrounding ionic concentration, hFNIII 9-10 was dissolved in distilled water, phosphate buffered saline and RPMI 1640. Optical density (O.D.) was measured in ELISA reader. Results. The results were as follows; 1. The adsorption of hFNIII 9-10 showed significantly highest mean optical density (O.D.) value in $80{\mu}g/ml$. 2. The difference of ionic composition in DW, PBS and RPMI did not influence the adsorption amount of hFNIII 9-10.