• Korean Journal of Materials Research
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• v.24 no.4
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• pp.201-206
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• 2014

TiC-21 mol% Mo solid solution (${\delta}$-phase) and TiC-99 mol% Mo solid solution (${\beta}$-phase), and TiC-(80~90) mol% Mo hypo-eutectic composite were deformed by compression in a temperature range from room to 2300 K and in a strain rate range from $4.9{\times}10^{-5}$ to $6.9{\times}10^{-3}/s$. The deformation behaviors of the composites were analyzed from the strengths of the ${\delta}$- and ${\beta}$-phases. It was found that the high strength of the eutectic composite is due primarily to solution hardening of TiC by Mo, and that the ${\delta}$-phase undergoes an appreciable plastic deformation at and above 1420 K even at 0.2% plastic strain of the composite. The yield strength of the three kinds of phase up to 1420 K is quantitatively explained by the rule of mixture, where internal stresses introduced by plastic deformation are taken into account. Above 1420 K, however, the calculated yield strength was considerably larger than the measured strength. The yield stress of ${\beta}$-phase was much larger than that of pure TiC. A good linear relationship was held between the yield stress and the plastic strain rate in a double-logarithmic plot. The deformation behavior in ${\delta}$-phase was different among the three temperature ranges tested, i.e., low, intermediate and high. At an intermediate temperature, no yield drop occurred, and from the beginning the work hardening level was high. At the tested temperature, a good linear relationship was held in the double logarithmic plot of the yield stress against the plastic strain rate. The strain rate dependence of the yield stress was very weak up to 1273 K in the hypo-eutectic composite, but it became stronger as the temperature rose.

• Restorative Dentistry and Endodontics
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• v.37 no.4
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• pp.201-206
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• 2012

Objectives: The purpose was to investigate the preference and usage technique of NiTi rotary instruments and to retrieve data on the frequency of re-use and the estimated incidence of file separation in the clinical practice among general dentists. Materials and Methods: A survey was disseminated via e-mail and on-site to 673 general dentists. The correlation between the operator's experience or preferred technique and frequency of re-use or incidence of file fracture was assessed. Results: A total of 348 dentists (51.7%) responded. The most frequently used NiTi instruments was ProFile (39.8%) followed by ProTaper. The most preferred preparation technique was crown-down (44.6%). 54.3% of the respondents re-used NiTi files more than 10 times. There was a significant correlation between experience with NiTi files and the number of re-uses (p = 0.0025). 54.6% of the respondents estimated experiencing file separation less than 5 times per year. The frequency of separation was significantly correlated with the instrumentation technique (p = 0.0003). Conclusions: A large number of general dentists in Korea prefer to re-use NiTi rotary files. As their experience with NiTi files increased, the number of re-uses increased, while the frequency of breakage decreased. Operators who adopt the hybrid technique showed less tendency of separation even with the increased number of re-use.

• Korean Journal of Metals and Materials
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• v.50 no.3
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• pp.201-205
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• 2012

The effects of various manganese precursors for the low-temperature selective catalytic reduction (SCR) of $NO_x$ were investigated in terms of structural, morphological, and physico-chemical analyses. $MnO_x/TiO_2$ catalysts were prepared from three different precursors, manganese nitrate, manganese acetate(II), and manganese acetate(III), by the sol-gel method. The manganese acetate(III)-$MnO_x/TiO_2$ catalyst tended to suppress the phase transition from the anatase structure to the rutile or the brookite after calcination at $500^{\circ}C$ for 2 h. It also had a high specific surface area, which was caused by a smaller particle size and more uniform distribution than the others. The change of catalytic acid sites was confirmed by Raman and FT-IR spectroscopy and the manganese acetate(III)-$MnO_x/TiO_2$ had the strongest Lewis acid sites among them. The highest de-NOx efficiency and structural stability were achieved by using the manganese cetate(III) as a precursor, because of its high specific surface area, a large amount of anatase $TiO_2$, and the strong catalytic acidity.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.201-206
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• 2021

Damage to the highly pathogenic avian influenza virus(H5N1) continues to increase, but there is a lack of antiviral research. In this study, we analyze antiviral properties on H5N1 by coating Cu/TiO2 photocatalyst on polyethylene films. The specimen was manufactured a photocatalyst master batch and coated both sides of the 3-layer polyethylene fabric at 280℃ from the extrusion coating machine. The results showed a 99.9% decrease in the Staphylococcus aureus and Escherichia coli. In particular, H5N1 type highly pathogenic avian influenza viruses, which is capable of human infection, has been found to decrease 99.9% within five minutes of contact with Cu/TiO2 films. Antibacterial effects of films coated with photocatalyst are known, but this study also confirmed the antiviral effects.

• Journal of Plant Biology
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• v.34 no.4
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• pp.331-339
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• 1991

To elucidate the regulatory mechanism of virE operon from vir regions (virA, virB, virC, virD, virG, virE) of pTiA6 which have been known to be essential for efficient crown gall tumorigenesis in plants, the activity of the truncated virE, promoter was analyzed. pSM358cd, a recombinant plasmid in which virE :: Tn3-HoHo1 (Tn3-promoterless lacZ) was cloned into SalI site of pVK102, was digested with SalI, and virE :: Tn3-HoHo1 was seperated from pVK102. To construct the truncted virE recombinant plasmids (pJS031, pJS051, pJS102, pJS201, pJS301), 5'-end of vireE promoter was deleted with BAL31 and cloned into pVK102 and then transferred into a. tumefaciens A348(pTiA6). According to the activity of the truncated virE promoter in recombinant plasmids, they were classified into two groups, pJS031, pJS051, pJS101 and pJS201 belong to a functional group and pJS301 is a non-functional. The size of deleted nucleotides of pJS201 and pJS301 seemed to be about 130 nucleotides and about 250 nucleotides from 5'-end of virE promoter, respectively. Hence it was thought that the essential site of the virE promoter was located between about 130th nucleotide and 250th nucleotide from 5'-end of the virE promoter.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.201-204
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• 2007

A novel self-humidifying composite membrane for the proton exchange membrane fuel cell (PEMFC) at low humidity condition was developed. The $Pt/TiO_2 catalyst particles were synthesized via supercritical impregnation methods. Pt precursor was dissolved in supercritical carbon dioxide and impregnated onto $TiO_2$ particles. Pt precursors were platinum(II) acetylacetonate, Dimethyl(1,5-cyclooctadiene) platinum(II) and we controlled the ratio of Pt to $TiO_2$ The impregnated Pt precursor was converted to $TiO_2$ supported Pt nanoparticle under various reducing conditions. $TiO_2$ catalyst particles were dispersed uniformly into the Nafion solution, and then $Pt/TiO_2/Nafion$composite membrane was prepared using solution-cast method. The size, dispersion and content of the platinum had been characterized with Transmission Electron Micrograph (TEM), X-ray diffract ion (XRD) and Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP-AES). The cell performance with the self-humidifying composite membrane was compared with a recast Nafion membrane under both humidified and dry conditions at 65 $^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.127-130
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• 2001

The $BaTiO_3+xNb_2O_5$(x=6, 8, 10wt%) ceramics were prepared by conventional mixed oxide method. The structural properties of the $BaTiO_3+Nb_2O_5$ ceramics with the sintering temperature and addition of $Nb_2O_5$ were investigated by XRD and SEM. Increasing the sintering temperature, the $2{\theta}$ value of BT(110) peak was shifted to the lower degree and intensity of the $Ba_6Ti_2Nb_8O_{30}$ (133) peak was increased. Increasing the addition of $Nb_2O_5$, the intensity of $BaTiNb_4O_{13}$ (201) peak was decreased and $Ba_6Ti_2Nb_8O_{30}$ (133) peak was increased. The grain size of the $BaTiO_3+Nb_2O_5$ ceramics sintered at $1500^{\circ}C$ were almost uniform.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.4
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• pp.339-341
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• 2007

A 22-year-old woman with a history of acute lymphoblastic leukemia was hospitalized for headache and vomiting. CT scan showed a well-defined, ring like enhancing mass in the left frontal lobe with surrounding edema and midline shift. Magnetic resonance imaging demonstrated a round homogeneous mass with a ring of enhancement in the left frontal lobe. Tl-201 brain SPECT showed increased focal uptake coinciding with the CT and MRI abnormality. Aspiration of the lesion performed through a burr hole yielded many neutrophils, a few lymphocytes and histiocytes with some strands of filamentous microorganism-like material. Modified AFB stained negative for norcardia. Gram stain showed a few white blood cells and no microorganism. Antibiotics were started and produced a good clinical response. After one month, CT scan showed markedly reduction in size and extent was observed.

• Journal of Plant Biology
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• v.35 no.2
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• pp.155-163
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• 1992

To elucidate the regulatory mechanism of virE operon in Agrobacterium tumefaciens pTiA6 plasmid at the molecular level, the regulatory site of virE promoter was determined using truncated virE recombinant plasmids obtained by 5' deletion analysis of virE promoter. The size of deleted nucleotides of p]S201, a functional recombinant plasmid, was found to be about 130 nucleotides from 5'-end of virE promoter. On the other hand the size of deleted nucleotides of p]S301, nonfunctional recombinant plasmid, was identified 263 nucleotides by DNA sequencing. Hence it was thought that the essential site of virE promoter was located between about 130th nucleotide and 263th nucleotide. Since the inverted repeat sequence (AACTTTGCGCTATAGGCAMGTT) is included in this essential site of virE promoter, it could be the first recognition site of the RNA polymerase in virE promoter.omoter.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.1
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• pp.14-17
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• 2011

Dwarfuess and Kunitz trypsin inhibitor (KTI) protein in soybean is useful traits for basic studies. df2 and ti gene control dwarfness and the expression of Kunitz trypsin inhibitor (KTI) protein in soybean, respectively. The objective of this research was to verify genetic linkage or independent inheritance of df2 and ti loci in soybean. The $F_2$ population was made by cross combination between "Gaechuck#2" (Df2Df2titi genotype, KTI protein absence and a normal growth type) and T210 (df2df2TiTi genotype, a dwarf growth type and KTI protein present). A total of 258 $F_2$ seeds were analyzed for the segregation of KTI protein using SDS-PAGE. And so, 198 $F_2$ plants were recorded for the segregation of dwarfness. The segregation ratio of 3 : 1 for Ti locus (201 Ti_ : 57 titi) and Df2 locus (143 Df2_ : 55 df2df2) was observed. Segregation ratio of 9 : 3 : 3 : 1 (116 Ti_Df2_: 44 Ti_df2df2: 27 titiDf2_: 11 titidf2df2) between df2 gene and ti gene was observed ($x^2$=3.53, P = 0.223). These results showed that df2 gene was inherited independently with the ti gene in soybean.