• Journal of Welding and Joining
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• v.33 no.5
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• pp.53-60
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• 2015

Laser surface Melting Process is getting hardening layer that has enough depth of hardening layer as well as no defects by melting surface of substrate. This study used CW(Continuous Wave) Yb:YAG and STD11. Laser beam speed, power and beam interval are fixed at 70mm/sec, 2.8kW and 800um respectively. Hardness in the weld zone are equal to 400Hv regardless of melting zone, remelting zone overlapped by next beam and HAZ. Similarly, microstructures in all weld zone consist of dendrite structure that arm spacing is $3{\sim}4{\mu}m$, matrix is ${\gamma}$(Austenite) and dendrite boundary consists of ${\gamma}$ and $M_7C_3$ of eutectic phase. This microstructure crystallizes from liquid to ${\gamma}$ of primary crystal and residual liquid forms ${\gamma}$ and $M_7C_3$ of eutectic phase by eutectic reaction at $1266^{\circ}C$. After solidification is complete, primary crystal and eutectic phase remain at room temperature without phase transformation by quenching. On the other hand, microstructures of substrate consist of ferrite, fine $M_{23}C_6$ and coarse $M_7C_3$ that have 210Hv. Microstructures in the HAZ consist of fine $M_{23}C_6$ and coarse $M_7C_3$ like substrate. But, $M_{23}C_6$ increases and matrix was changed from ferrite to bainite that has hardness above 400Hv. Partial Melted Zone is formed between melting zone and HAZ. Partial Melted Zone near the melting zone consists of ${\gamma}$, $M_7C_3$ and martensite and Partial Melted Zone near the HAZ consists of eutectic phase around ${\gamma}$ and $M_7C_3$. Hardness is maximum 557Hv in the partial melted zone.

• Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.200-205
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• 2002

Temperature-dependent pharmacokinetics of ciprofloxacin (CIP) was studied in the cultured olive flounders, Paralichthys olivaceus, and black rockfish, Sebastes schlegeli using high performance liquid chromatography (HPLC) originally developed for quinolone determination from livestock. Pharmacokinetics of CIP was apparently affected by ambient water temperature. In a two-compartment model for flounders after oral dosage of 20 mg/kg, $K_{01},\;at\;13^{\circ}C$ and $23^{\circ}C$ were 4.18 and 1.20/hr, respectively. The $K_{10},\;T_{max}\;and\;C_{max}\;at\;13^{\circ}C$ were 5.574/hr, l4.37${\mu}g/mL\;and\;3.15{\mu}g/mL,$ respectively. The corresponding values at $23^{\circ}C$ were l2.84/hr, 15.39${\mu}g/mL\;and\;6.38{\mu}g/mL$, respectively. The AUC, $T_{1/2} (\alpha)\;and\;T_{1/2}\;(\beta)$ were 278.23 ${\mu}g \cdot hr/mL$, 0.24hr and 47.02hr at $13^{\circ}C$ and 3l7.8l${\mu}g \cdot hr/mL$, 0.30 hrs and 60.78hrs at $23^{\circ}C$ for the flounder, respectively. Similar CIP pharmacokinetics were revealed in the black rockfish after oral dosage of 20 mg/kg under the two water temperature regimes. These pharmacokinetical results have some implication in the optimal usage of recently introduced antibacterials in the farmed fish, which were primarily adapted for poultry and mammalian species.

• Applied Biological Chemistry
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• v.25 no.2
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• pp.67-74
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• 1982

Morphology, physicochemical properties, pasting properties in the presence of various anionic ions and aging of gels of Akibare (Japoica type) and Milyang 23 (Indica type) rice starch were studied, Both starches. were polygonal with length in the range of $3{\sim}6{\mu}m$. Starch granules of Akibare were somewhat smaller than those of Milyang 23. X-ray diffraction study demonstrated that peak shape and intensity were significantly different between the two starches. Akibare and Milyang 23 rice starch had amylose content of 18.5 and 19.5% and water binding capacity of 106 and 100%, respectively. Milyang 23 rice starch had a higher swelling power than Akibare starch. A relationship between percent solubility and swelling power implied that bonding forces within the granules of the both starches were different. The optical transmittance of 0.1% suspension of the two starches increased rapidly from $60^{\circ}C$. In the range of $60{\sim}90^{\circ}C$, the two starches showed a single gelatinization pattern. Amylograms of the two starches in the presence of various anionic ions showed that pasting temperature and peak temperature were progressively increased in the order of SCN-${SO_4}^=$. SCN- and I- ions increased the peak height of Akibare rice starch while only SCN- ion was effective for Milyang 23 rice starch. There were no differences in the rates of retrogradation of 45% gels of the two starches stored at $21^{\circ}C$.

• Journal of the Korean Society for Heat Treatment
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• v.19 no.1
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• pp.10-19
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• 2006

Microstructure and morphology of precipitates in $Ni_3Al$- and TiAl-based intermetallics containing carbon have been investigated in terms of transmission electron microscopy(TEM). In an $L1_2$-ordered $Ni_3Al$ alloy with 4 mol.% of chromium and 0.2~3.0 mol.% of carbon, fine octahedral precipitates of $M_{23}C_6$ type carbide were formed in the matrix by aging at temperatures around 973 K after solution annealing at 1423 K. TEM examination revealed that the $M_{23}C_6$ phase and the matrix lattices have a cube-cube orientation relationship and keep partial atomic matching at the {111} interface. After prolonged aging or by aging at higher temperatures, the $M_{23}C_6$ precipitates then adopt a rod-like morphology elongated parallel to the <100> directions. In the $L1_0$-ordered TiAl containing 0.1~2.0 mol.% carbon, TEM observations revealed that needle-like precipitates, which lie only in one direction parallel to the [001] axis of the $L1_0$ matrix, appear in the matrix and preferentially at dislocations. Selected area electron diffraction(SAED) patterns analyses have shown that the needle-shaped precipitate is $Ti_3AlC$ of perovskite type. The orientation relationship between the $Ti_3AlC$ and the $L1_0$ matrix is found to be $(001)_{Ti3AlC}//(001)_{L10\;matrix}$ and $[010]_{Ti3AlC}//[010]_{L10\;matrix}$. By aging at higher temperatures or for longer period at 1073 K, plate-like precipitates of $Ti_2AlC$ with a hexagonal structure are formed on the {111} planes of the $L1_0$ matrix. The orientation relationship between the $Ti_2AlC$ and the $L1_0$ matrix is $(0001)_{Ti2AlC}//(111)_{L10\;matrix}$ and $_{Ti2AlC}//_{L10\;matrix}$.

• Journal of the Korean Society for Heat Treatment
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• v.7 no.1
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• pp.25-34
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• 1994

To investigate the effect of austenitizing tempratures on the mechanical properties and corrosion resistance of 0.19%C-13.6%Cr martensitic stainless steel, the changes in martensitic trasformation temperatures, mechanical properties and anodic polarization curve were examined after changing the austenitizing temperatures and tempering temperatures. On increasing heating rate at the same austenitizing temperatures, $A_s$, $A_r$ and $M_s$ increased. And the $M_s$ temperature showed to be decreased with increasing austenitizing temperature. With increasing tempering temperature up to $500^{\circ}C$, strength, hardness and impact value were not changed remarkably, on the other hand the tensile strength and hardness decreased and impact value increased after tempering above $550^{\circ}C$ owing to the $M_{23}C_6$ carbide precipitation. The abrupt decrease in elongation at the tempering temperture of $500^{\circ}C$ proved to the precipitation of $M_7C_3$ carbide. The effect of austenitizing temperature on the mechanical properties of the tempered specimen showed to be decreased in impact value and elongation at the austenitizing temperature of $1150^{\circ}C$. At low tempering temperatures the corrosion resistance of the tempered specimen was not changed obviously with increasing tempering temperature. On the other hand, the resistance decreased above the tempering temperature of $600^{\circ}C$ due to the precipitation of $M_{23}C_6$ carbides. The corrosion resistance showed to be improved with increasing the austenitizing temperature owing to the dissolution of carbides.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.1
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• pp.32-43
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• 1996

A $CdIn_{2}Te_{4}$ single crystal was grown by modified veritical bridgman method. The $CdIn_{2}Te_{4}$ single crystal was evaluated to be tetragonal by the powder method. The $CdIn_{2}Te_{4}$ single crystal was confirmed to be grown with its c axis along the lengthe of the boule by the Laue reflection method. Hall effect of $CdIn_{2}Te_{4}$ single crystal was estimated by van der pauw method from 293 K to 30 K. Hall data of the sample perpendicular to c axis was $n=8.75{\times}10^{23}electrons/m^{3},\;R_{H}=7.14{\times}10^{-5}m^{3}/C,\;{\sigma}=176.40{\omega}^{-1}m^{-1},\;{$\mu}=3.41{\times}10^{-2}m^{2}/V.s$ and the sample parallel to c axis was $n=8.61{\times}10^{23}electrons/m^{3},\;R_{H}=7.26{\times}10^{-5}m^{3}/C,\;{\sigma}=333.38{\omega}^{-1}m^{-1}\;and\;{$\mu}=2.42{\times}10^{-2}m^{2}/V.s$ for room temperature. The value of Hall coefficient on sample perpendicular or parallel to c axis were positive. There $CdIn_{2}Te_{4}$ single crystal was p-type semiconductor.

• The Korean Journal of Soil Zoology
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• v.4 no.2
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• pp.89-100
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• 1999

Four new and a known spacies of the order Mononchida were described and illustrated. Iotonchus obtusus sp. n. was 2.8 mm long, a=33, b=4.2, c=61, V=68%, buccal cavity=61${\times}$45 mm, and is characterized by having basally situated dorsal tooth, presence of vulval papillae and in having short, hemispherical tail with thick cuticle at terminus. Miconchus vulvapapillatum sp. . was 2.7-3.6 mm long, a=29-36, b=4.1-4.5, c=18.4-21, V=65-69%, buccal cavity=53-61${\times}$29-33 mm, spicules=132-137 mm, ventromedian supplements 28-31, and was characterized by having 5-8 pre- and post vulval papillae in contiguous series, and three pairs of vulval glands. Clarkus koreanus sp. n. was 1.1-1.3 mm long, a=27.5-28.8, b=3.5-3.9, c=12-14.5, V=60-64%, buccal cavity=24-28${\times}$13.5-15 mm, and was characterized by well offset lip region, amphids situated well below to dorsal tooth apex, and vulva elevated, with vulval flap. Coomansus ulsani sp. n. was 1.2-1.5 mm long, a=23.5-26, b=3.4-3.8, c=13.6-14.8, V=65-68%, buccal cavity=36-39${\times}$21-23 mm and was characterized by well offset lip region and a thin longitudinal ridge on vertical walls of stoma.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.349-354
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• 2013

This study examined a technique for cooling root zone aimed at lowering substrate temperature for sweet pepper (Capsicum annum L. 'Orange glory') cultivation in coir substrate hydroponics during hot season, from the $16^{th}$ of July to $15^{th}$ of October in 2012. The root zone cooling technique was applied by using an air duct (${\varnothing}12$ cm, hole size 0.1 mm) to blow cool air between two slabs during night (5p.m. to 3a.m.). Between the $23^{rd}$ of July and $31^{st}$ of August (hot temperature period), average daily substrate temperature was $24.7^{\circ}C$ under the root zone cooling, whereas it was $28.2^{\circ}C$ under condition of no cooling (control). In sunny day (600~700 W $m^{-2}{\cdot}s^{-1}$), average substrate temperatures during the day (6a.m. to 8p.m.) and night (8p.m. to 6a.m.) were lower about $1.7^{\circ}C$ and $3.3^{\circ}C$, respectively, under the cooling treatment, compared to that of control. The degree of temperature reduction in the substrate was averagely $0.5^{\circ}C$ per hour under the cooling treatment during 6p.m. to 8p.m.; however, there was no decrease in the temperature under the control. The temperature difference between the cooling and control treatments was $1.3^{\circ}C$ and $0.6^{\circ}C$ in the upper and lower part of the slab, respectively. During the hot temperature period, about 32.5% reduction in the substrate temperature was observed under the cooling treatment, compared to the control. Photosynthesis, transpiration rate, and leaf water potential of plants grown under the cooling treatment were significantly higher than those under the control. The first flowering date in the cooling was faster about 4 days than in the control. Also, the number of fruits was significantly higher than that in the control. No differences in plant height, stem thickness, number of internode, and leaf width were found between the plants grown under the cooling and control, except for the leaf length with a shorter length under the cooling treatment. However, root zone cooling influenced negligibly on eliminating delay in fruiting caused by excessively higher air temperature (> $28^{\circ}C$), although the substrate temperature was reduced by $3^{\circ}C$ to $5.6^{\circ}C$. These results suggest that the technique of lowering substrate temperature by using air-duct blow needs to be incorporated into the lowering growing temperature system for growth and fruit set of health paprika.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.6
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• pp.605-611
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• 1990

$\beta$-Galactosidase activity was not detected at green mature stage but were 21.79 and 380.23 units/100g-fr. wt. in mature and soft persimmon, respectively. The molecular weight of $\beta$-galactosidase was estimated to be 115, 000 daltons by the method of gel filtration. Vmax and Km value were 0.095m mo1e p-nitrophenyl-galactoside and 1.8$\times$10$^{-2}$ mM, respectively. The optimum temperature and pH of $\beta$-galactosidase were 45$^{\circ}C$ and 4.2, respectively. $\beta$-Galactosidase was inhibited by SDS.

• Applied Biological Chemistry
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• v.33 no.4
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• pp.325-329
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• 1990

This study was undertaken to determine thermodynamic characteristics of B. subtilis p-4 and B. licheniformis p-5 proteases isolated from fermented anchovy paste. $K_m$ values of two proteases for casein as a substrate were 0.38mM in p-4 protease and 0.18mM in p-5 protease, respectively. Denaturation constants($K_D$) of p-4 and p-5 proteases were $12.2{\times}10^{-5}/sec\;and\;19.0{\times}10^{-5}/sec\;at\;40^{\circ}C,\;and\;35.7{\times}10^{-5}/sec\;and\;46.3{\times}10^{-5}/sec\;at\;50^{\circ}C$, respectively. Activation energies($E_a$) of p-4 and p-S pmteases were 19.6 Kcal/mole and 15.2kcal/mole, respectively. Free energy of activation(${\Delta}G^*$), activation enthalpy(${\Delta}H^*$) and activation entropy(${\Delta}S^*$) at $40^{\circ}C$ were 23.21Kcal/mole, 18.98Kcal/mole and -13.50 eu, respectively for p-4 protease and 22.93Kcal/mo1e, 14.58Kcal/mole and -26.68 eu, respectively for p-5 protease. The major amino acids in p-4 protease(151 residues of amino acid) were Gly, Glu, Pro, Asp, Ser, Ala, Lys and Leu, while those in p-5 protease(247 residues of amino acid) were Gly, Glu, Asp, Ala and Leu. It may be concluded that heat denaturation of two proteases showed liner regression curve and p-5 protease was more sensitive to heat than p-4 protease.