• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.2
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• pp.137-143
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• 2008

Rapid canopy closure (RCC) is one of the physiological attributes that may enhance genetic yield potential of rice (Oryza sativa L.) in a growing season. Crop growth before canopy closure could be described by an exponential equation of $y\;=\;{\alpha}{\cdot}{\exp}({\beta}{\cdot}t)$ where $\alpha$ is the crop leaf area index (LAI) or shoot dry weight (DW), t is the thermal time, $\beta$ is the LAI or DW at the beginning of the exponential growth and is the relative growth rate of LAI ($m^2m^{-2}^{\circ}C^{-1}$) or DW($gg^{-2}^{\circ}C^{-1}$). Field experiment using 22 cultivars revealed that the exponential growth phase before canopy closure can be divided into two sections; an earlier section during which crop dry weight and LAI of varieties are highly dependent on $\alpha$ and a second section where crop dry weight and LAI are highly dependent on $\beta$. Grain weight had significantly positive correlation with $\alpha$ parameter and dry weight and LAI during early exponential phase. The parameter $\beta$ of the exponential growth curve had positive and significant correlation with the LAI and dry weight during the late exponential growth phase, grain number per unit area, and grain yield. There was genotypic difference for RCC parameters, $\alpha$ and $\beta$, indicating the possibility of genetic improvement for these traits.

• Journal of the Korean Society for Heat Treatment
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• v.18 no.2
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• pp.91-98
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• 2005

Both commercially pure titanium and Ti-6Al-4V alloy have been widely used as biomaterials because of their excellent biocompatibility, corrosion resistance and mechanical properties. However, in recent years, vanadium has been found to cause cytotoxic effects and adverse tissue reactions, while aluminium has been associated with potential neurological disorders. A newly designed ${\alpha}+{\beta}$ type Ti alloy, Ti-10Ta-10Nb alloy showed superior properties to CP Ti and Ti-6Al-4V alloy in the point of biomaterial, and elucidated the future uses as a biomaterial. Microstructural changes of Ti-10Ta-10Nb alloy after hot-rolling, warm-rolling, solution and aging treatment were investigated. According to TEM results, the microstructures after solution treatment were composed of mostly ${\alpha}$ phase with a trace of ${\beta}$ phase due to adding ${\beta}$-phase stabilizer tantalum and niobium. The microstructures after warm-rolling is coarse and elongated ${\alpha}$ phase and hot rolling resulted in very fine ${\alpha}$ widmanst$\ddot{a}$tten. The highest value of hardness was obtained by aging treatment at $400^{\circ}C$ for 20hr in which microstructure consisted of very fine ${\alpha}$ phase in ${\beta}$ matrix.

• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1106-1112
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• 2003

For the purpose of making clear the role of oxygen in the thermoelectric properties of FeSi$_2$, thermoelectric measurements and spectroscopic characterization were conducted for the oxidized specimens fabricated from ($\alpha$+$\varepsilon$)-phases and/or $\beta$-phase. Addition of oxygen to FeSi$_2$ prevented both densification during sintering and transformation from metallic phases to semiconducting phase during annealing treatment. In an specimens, electrical conductivity and thermal conductivity decreased with oxidation time. The Seebeck coefficient was positive and small for pure FeSi$_2$. And/or the oxidized specimens fabricated from ($\alpha$+$\varepsilon$)-phases. However, it was negative and showed a maximum peak at about 500 K for the oxidized FeSi$_2$ fabricated from $\beta$-phase. The value of maximum peak increased with oxidation time.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.2
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• pp.68-72
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• 2002

The $\beta$-$FeSi_2$ and $\alpha$-$FeSi_2$ single crystals were synthesized by chemical vapour transport (CVT) using iodine as a transporting agent from the commercially available $FeSi_2$ powder. The $FeSi_2$ powder together with iodine were sealed in an evacuated quartz ampoule and the ampoule then being placed in two-zone electrical furnace for growing crystal. The CVT of $FeSi_2$ with iodine yielded $\beta$-$FeSi_2$ and $\alpha$-FeSi$_2$ single crystals at deposition temperature of 750 and $950^{\circ}C$ respectively. The source temperature was $1050^{\circ}C$ in both cases. The crystals of the $\alpha$-FeSi$_2$ phase were typically plate shaped with dimensions of about $10\times 10 \textrm{mm}^2$, whereas the crystals of orthorhombic $\beta$-$FeSi_2$ phase grew predominantly in the fonts of thin needle of about 10 mm in length. The composition of$\alpha$-FeSicrystal determined by electron probe microanalysis (EPMA) resulted in Si-rich $FeSi_{2.58}$ . 57. Furthermore, the CVT $\beta$-$FeSi_2$ crystal was found to be transformed to the high temperature $\alpha$-$FeSi_2$phase above $930^{\circ}C$.

• Journal of the Korean Chemical Society
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• v.36 no.4
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• pp.504-510
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• 1992

Absorption properties of methylene blue (MB) in L-${\alpha}$-lecithin vesicle, bacteriorhodopsin and incorporated bacteriorhodopsin (InBR) vesicle systems at 20∼$60^{\circ}C$ has been studied by adsorption spectroscopy. The equilibrium of MB between monomer and dimer in lecithin vesicles has been existed at low concentration of MB, but oligomer has been formed in vesicle at higher concentration of MB. In most cases, the MB cluster was redistributed to monomer at the concentration of lecithin vesicles. Adding BR to constanr concentration of MB deceased the adsorption ratio (${\alpha}/{\beta}$) of MB, and MB was formed oligomeric aggregate. Absorption ratio (${\alpha}/{\beta}$) of MB was increased during phase transition of InBR vesicles, but independent of phase transition of lecithin vesicles. It suggested that aggregate of MB on the surfaces of InBR vesicles were redistributed to monomer under the influence of lipid phase transition.

• Applied Microscopy
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• v.25 no.3
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• pp.90-98
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• 1995

In the Fe-Si system, a mixture of a($Fe_{2}Si_5$) - and ${\epsilon}$(FeSi)-composition powders was sintered and heat-treated subsequently at various temperatures and time to get thermoelectric ${\beta}$-phase($FeSi_2$) compacts. The different transformational sequences depending on the heat treating temperature were found through the investigation into phase transformation and microstructural development. That is, a rapid eutectoid decomposition of ${\alpha}{\to}{\beta}+Si$ occurred together with a accompanying slow reaction between the dispersed Si formed by above decomposition and the preexisted ${\epsilon}$ phase at temperatures below $830^{\circ}C$. The unreacted Si and the micropores formed due to the density change upon the transformation coarsened as heat treating time elapsed. At temperatures above $880^{\circ}C$, however, transformation was proceeded by a peritectoid reaction of ${\alpha}+{\epsilon}{\to}{\beta}$. It took at least 200min. to achieve 90% volume fracion of transformed ${\beta}$ phase, and the growth of micro-pores was also observed in this transformational sequence with prolonged heat treating time.

• Parasites, Hosts and Diseases
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• v.49 no.2
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• pp.191-194
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• 2011

Sparganosis is a tissue invading helminthiasis infecting intermediate hosts, including humans. Strong immune responses are expected to occur in early phases of infection. Thus, we investigated cytokine expressions in splenic dendritic cells and in sera after experimental infection of mice. In splenic dendritic cells, TNF-${\alpha}$ and IL-$1{\beta}$ expression peaked at week 1 and week 3 post -infection (PI), respectively, and also early phase (week 2 PI) depressed cytokine expression was noticed. Serum IL-$1{\beta}$ concentration increased significantly at week 2 PI and peaked at week 6 PI, and that of TNF-${\alpha}$ peaked at week 6 PI. These results showed that pro-inflammatory cytokines, TNF-${\alpha}$ and IL-$1{\beta}$, are chronologically regulated in mouse sparganosis.

• Korean Journal of Veterinary Research
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• v.33 no.4
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• pp.611-615
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• 1993

A rapid, solid-phase microtitre plate enzyme immunoassay(EIA) to determine the concentration of progesterone and testosterone in dairy cow is described. Both steroid hormones were analysed employing antibodies against $11{\alpha}$-hemisuccinate-progesterone bovine serum albumin and 4-androsten-$17{\beta}$-ol-3-one-carboxymethyloxime bovine serum albumin, respectively. as primary antibodies and sheep Ig G as secondary antibody. The conjugated used as labels for progesterone and testosterone was progesterone-$11{\alpha}$-hydroxy-hemisuccinate- horseradish peroxidase and 4 ${\alpha}$-androsten-$17{\beta}$-ol-3-hemisuccinate- horseradish peroxidase, respectively. Detection limit of microtitre plate EIA was 6.7 pg/well for progesteone and 1.0 pg/well for testosterone.

• Bulletin of the Korean Chemical Society
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• v.8 no.5
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• pp.398-403
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• 1987

A general theory of polymer adsorption at a semi-permeable oil-water interface of the biphasic solution is presented. The configurational factor of the solution in the presence of the semi-open boundary at the interface is evaluated by the quasicrystalline lattice model. The present theory gives the feature of the bulk concentration equilibria between oil-water subsystems and the surface excesses of ${\Gamma}^{\alpha}$ and ${\Gamma}^\{beta}$ of the polymer segments as a function of the degree of polymerization $\gamma$, the Flory-Huggins parameter in $\beta$-phase $x_{\rho}^{{\beta}_{\rho}}$, the differential adsorption energy parameter in $\beta$-phase $x_{\sigma}^{{\beta}_{\rho}}$, the differential interaction energy parameter ${\Delta}x_{\rho}$ and the bulk concentration of the polymer in ${\beta}-phase ${\varphi}_2^{{\beta(*)}_2}$. From our numerical results, the characteristics of ${\Gamma}^{\alpha}$ are shown to be significantly different from those of ${\Gamma}^{\beta}$ in the case of high polymers, and this would be the most apparent feature of the adsorption behavior of the polymer at a semi-permeable oil-water interface, which is sensitively dependent on ${\Delta}x_{\rho}$ and r.

• Journal of Powder Materials
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• v.4 no.3
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• pp.179-187
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• 1997

Milling media of steel and zirconia were used to produce $MoSi_2$ by mechanical alloying (MA) of Mo and Si powders. The effect of milling media on MA of Mo-65.8at%Si powder mixture has been investigated by SEM, XRD, DTh and in-situ thermal analysis. The powders mechanically alloyed by milling medium of steel for 8 hours showed the structure of fine mixture of Mo and Si, and those mechanically alloyed by milling medium of zirconia for longer milling time showed the structure of fine mixture of Mo and Si. The tetragonal $\alpha$-$MoSi_2$ Phase and the tetragonal $Mo_5Si_3$ phase appeared with small Mo peaks in the powders milled by milling medium of steel for 4 and 8 hours. The $\alpha$-$MoSi_2$ phase and the hexagonal $\beta$-$MoSi_2$ phase were formed after longer milling time. The $\alpha$-$MoSi_2$ phase appeared with large Mo peaks in the powders milled by milling medium of zirconia for 4 hours. The phases, $\alpha$-$MoSi_2$ and $\beta$-$MoSi_2$. were formed in the powders milled for longer milling time. DTA and annealing results showed that Mo and Si were transformed into $\alpha$-$MoSi_2$ and $Mo_5Si_3$, while $\beta$-$MoSi_2$ into $\alpha$-$MoSi_2$. In-situ thermal analysis results demonstrated that there were a sudden temperature rise at 212 min and a gradual increase in temperature in case of milling media of steel and zirconia, respectively. The results indicate that MA can be influenced by materials of milling medium which can give either impact energy on powders or thermal energy accumulated in vial.