• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1889-1892
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• 2004

The peroxidase activity of cytochrome c was studied by using a chromogen, 2,2'-azinobis-(2-ethylbenzthiazoline-6-sulfonate) (ABTS). Initial rate of ABTS oxidation formation was linear with respect to the concentration of cytochrome c between 2.5-10 ${\mu}$M and $H_2O_2$ between 0.1-0.5 mM. The optimal pH for the peroxidase activity of cytochrome c was 7.0-8.5. The peroxidase activity retained about 40% of the maximum activity when exposed at 60 $^{\circ}C$. for 10 min. The peroxidase activity showed a typical Michaelis-Menten kinetics for $H_2O_2$ which Km value was 29.6 mM. Radical scavengers inhibited the peroxidase activity of cytochrome c. The peroxidase activity was significantly inhibited by the low concentration of iron chelator, deferoxamine. The results suggested that the peroxidase activity was associated with iron in the heme of cytochrome c.

• Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.373-378
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• 2015

Postprandial ammonia excretion and oxygen consumption in olive flounder Paralichthys olivaceus fed two different feed types, moist pellet (MP) and expanded pellet (EP) diets, to satiation were determined at $12^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$, and $25^{\circ}C$ for 48 h. The ammonia excretion and oxygen consumption rates increased with increasing water temperature. However, the postprandial times for the maximum rates of ammonia excretion and oxygen consumption were shortened from 12 h to 6 h after feeding with increasing water temperature. The ammonia excretion and oxygen consumption rates of the fish fed EP were significantly higher (P < 0.05) than those fed MP at 12 h post-feeding both for $12^{\circ}C$ and $15^{\circ}C$. The highest (P < 0.05) weight-specific ammonia excretion rates at $12^{\circ}C$ were observed in the fish fed EP and MP at $12.1mg\;NH_3-N\;kg^{-1}h^{-1}$ and $8.7mg\;NH_3-N\;kg^{-1}h^{-1}$, respectively, for 12 h and 9 h after feeding. The highest (P < 0.05) weight-specific oxygen consumption rates at $12^{\circ}C$ were observed in fish fed EP and MP at $116.4mg\;kg^{-1}h^{-1}$ and $101.0mg\;kg^{-1}h^{-1}$, respectively, for 12 h after feeding. The highest ammonia excretion rates at $25^{\circ}C$ in the fish fed EP and MP increased to $16.9mg\;NH_3-N\;kg^{-1}h^{-1}$ and $18.3mg\;NH_3-N\;kg^{-1}h^{-1}$, respectively, for 6 h after feeding. The highest (P < 0.05) weight-specific oxygen consumption rates at $25^{\circ}C$ were observed in fish fed EP and MP at $184.3mg\;O_2kg^{-1}h^{-1}$ and $197.3mg\;O_2kg^{-1}h^{-1}$, respectively. These data are valuable for the design of biofilters and development of effluent treatment technologies for the land-based flounder farms.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.9
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• pp.510-515
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• 2000

The mechanical and electrical properties of the hot-pressed and annealed $\beta-SiC-TiB_2$ electroconductive ceramic composites were investigated as a function of the liquid forming additives of Al_2O_3+Y_2O_34. The result of phase analysis of composites by XRD revealed $\alpha-SIC(6H)\;TiB_2,\; and YAG(Al5Y3O12) crystal phase. The relative density and the mechanical properties of composites were increased with increasing $Al_2O_3+Y_2O_34 contents because YAG of reaction between $Al_2O_3\; and\; Y_2O_3$ was increased. The Flexural strength showed the highest value of 432.5MPa for composites added with 12wt% $Al_2O_3+Y_2O_34 additives at room temperature. Owing to crack deflection crack bridging phase transition and TAG of fracture toughness mechanism the fracture toughness showed 7.1MPa.m1/2 for composites added with 12wt% $Al_2O_3+Y_2O_34 additives at room temperature. The electrical resistivity and the resistance temperature coefficient showed the lowest of $6.0\times10-4\Omega.cm\; and\; 3.1\times10-3/^{\circ}C4 respectively for composite added with 12wt% \Omega additives at room temperature. The electrical resistivity of the composites was all positive temperature coefficient resistance (PTCR) in the temperature range of $25^{\circ}C\; to\; 700^{\circ}C$.

• Food Science and Preservation
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• v.5 no.3
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• pp.224-230
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• 1998

In order to establish proper storage conditions for ginger, the quality changes of gingers stored at three different temperatures(7$^{\circ}C$, 12$^{\circ}C$ and 20$^{\circ}C$) and three different relative humidities(75%, 85% and 95%RH) were investigated during 150 days of storage. Gingers stored at 7$^{\circ}C$ and 20$^{\circ}C$ showed rapid quality deterioration due to chilling injury and spouting respectively in any range of relative humidity. Ginger stored at 7$^{\circ}C$ was staled to show symptoms of the chilling injury such as moldiness, shrivelling, discoloration etc after 30 days of storage ; then it was deteriorated after 90 days of storage. Ginger stored at 20$^{\circ}C$ was completely lost its storage-life after 30 days of storage because of high sprouting ratio. However ginger stored at 12$^{\circ}C$, 75%RH showed better quality than ones stored at both 7$^{\circ}C$ and 20$^{\circ}C$, but it was not so good as the one at 7$^{\circ}C$, 95%RH. Consequently storage conditions of 12$^{\circ}C$, 95%RH was observed the best effecive condition for keeping rhizomes in good quality from weight loss, spouting, mouldiness and so on.

• Korean Journal of Materials Research
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• v.12 no.1
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• pp.48-53
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• 2002

$Al_2O_3-SiC$ and $Al_2O_3-SiC$-TiC composite powders were prepared by SHS process using $SiO_2,\;TiO_2$, Al and C as raw materials. Aluminum powder was used as reducing agent of $SiO_2,\;TiO_2$ and activated charcoal was used as carbon source. In the preparations of $Al_2O_3-SiC$, the effect of the molar ratio in raw materials, compaction pressure, preheating temperature and atmosphere were investigated. The most important variable affecting the synthesis of $Al_2O_3-SiC$ was the molar ratio of carbon. Unreactants remained in the product among all conditions without compaction. The optimum condition in this reaction was $SiO_2$: Al: C=3: 5: 5.5, 80MPa compaction pressure under Preheating of $400^{\circ}C$ with Ar atmosphere. However there remains cabon in the optimum condition. The effect of $TiO_2$ as additive was investigated in the preparations of $Al_2O_3-SiC$. As a result of $TiO_2$ addition, $Al_2O_3-SiC$-TiC composite powder was prepared. The $Al_2O_3$ powder showed an angular type with 8 to $15{\mu}m$, and the particle size of SiC powder were 5~$10{\mu}m$ and TiC powder were 2 to $5{\mu}m$.

• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.128-133
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• 2017

To determine the optimum water temperature (a temperature which minimizes metabolic activities and stress in fish) for long distance transportation of red-spotted grouper (Epinephelus akaara), by evaluating the behavior, survival and physiological and hematological responses to variable water temperature conditions (9, 12, 15, 18 and $21^{\circ}C$) for 48 hours. Fish exposed to $9^{\circ}C$ died at 48 hours exposure, but those exposed to 12, 15, 18 and $21^{\circ}C$ treatment groups all survived. Fish in the 15, 18 and $21^{\circ}C$ exposure groups exhibited normal swimming, while those exposed to $12^{\circ}C$ were observed to be stationary at the bottom of the tank. The plasma cortisol and glucose concentration were higher in fish exposed to $12^{\circ}C$ than at other temperature conditions. The fish in the 12 and $15^{\circ}C$ groups had significantly higher hematocrit (Ht) and hemoglobin (Hb) than those in the 18 and $21^{\circ}C$ groups (P<0.05). Levels of aspartate aminotransferase (AST), $NH_3$ and osmolality showed a pattern similar to the levels of plasma cortisol, while alanine aminotransferase (ALT) and total protein did not significantly vary among the experimental groups. These results indicate that the optimum water temperature for long distance transportation of the red-spotted grouper is $15^{\circ}C$.

• Korean Journal of Crystallography
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• v.2 no.1
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• pp.12-16
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• 1991

C18H22N4OS, Mr=342.47, monoclinic, P2₁/c,a=11.802(2), b=31.962(2), c=9.829(2)A, β=100.12(1)˚, V=3694.8A3,F(000)=1472, Z=8, Dx=1.246 Mg m-3, Dm=1.17Mg m-3,λ=0.71073 A, μ=0.15mm-1, T=294 K. final R=0.0856 for 3718 observed reflection (Fo>3σ(Fo)) There are two molecules in an asymmetric unit and a major difference between these molecules is in the C(9)-N(1)-C(6)-C(7) torsion angles [58.8(8)˚and 1(1)˚]. Both molecules have intramolecular N(1)-H(10)'N(3) hydrogen bonds [ 2.613(7) and 2.566(7) A] and assume V-shaped conformation with N(2) atoms at the verices. The two independent molecules are linked by the two N(2)-H(11)'S' hydrogen bonds[3.367(5) A and 3.421(4)A] and the dimergen are held together by van der Waals forces.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1527-1530
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• 2002

1,12-diazacyclodocosane-2,11-dione was first isolated from a plant Phyllanthus niruri Linn. Its structure has been determined by means of spectroscopy methods and X-ray crystallography. Two peptide groups in the big ring (lactam) are the main factors influencing intermolecular contacts. The hydrogen-bond interaction of these hydrophilic groups is observed in the crystal structure. Meanwhile, C-H···O hydrogen bonds in molecules contribute to the formation of the whole crystal. These two kinds of hydrogen-bond form six- member rings among molecules. This compound crystallizes in the triclinic space group P-1 with a= 9.588(1) $\AA$, b= $9.850(1)\AA$, c = $11.810(1)\AA$, $\alpha=$ 68.18(1)$^{\circ}C$ , $\beta=$ 84.98(1), $\gamma$ = 86.03(1)$^{\circ}C$ , V = $1030.66(17)\AA3$ , Z = 2. A disorder of five-member carbon chain in the whole ring is observed in the title compound. The bond angle 105.8(4) is determined for a extreme configuration C(14)-C(15)-C(16), and 117.7(10) for another extreme configuration C(14')-C(15')-C(16'). In this crystal, two molecules are tied each other by short intermolecular hydrogen bonds, the oxygen atom being tied by hydrogen bond to nitrogen atom of another two molecules. The NMR and IR spectral data coincides to the structure of the compound.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.10
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• pp.500-503
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• 2001

The mechanical and electrical properties of the hot-pressed and pressureless annealed SiC+39vol.%$TiB_2$electroconductive ceramic composites were investigated as a function of the liquid additives of $Al_2O_3+Y_2O_3$. The result of phase analysis for the SiC+39vol.%$TiB_2$composites by XRD revealed $\alpha$-SiC(6H), $TiB_2$, and $YAG(Al_5Y_3O_{12})4 crystal phase. The relative density of SiC+39vol.%$TiB_2$ composites was increased with increased $Al_2O_3+Y_2O_3$. contents. The fracture toughness showed the highest value of $7.8 MPa.m^{1/2}$ for composites added with 12 wt % $Al_2O_3+Y_2O_3$. additives at room temperature. The electrical resistivity and the resistance temperature coefficient showed the lowest value of $7.3\times10_{-4}\Omega.cm\; and\; 3.8\times10_{-3}/^{\circ}C$ for composite added with 12 wt% $Al_2O_3+Y_2O_3$. additives at room temperature. The electrical resistivity of the SiC+39vol.%$TiB_2$composites was all positive temperature coefficient resistance(PTCR) in the temperature ranges from $25^{\circ}C\; to\; 700^{\circ}C$.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.19-19
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• 2003

This presentation reviewed the dietary vitamin C requirements in main marine finfish culture in Korea. In experiment I, an II-week feeding trial was conducted to study the effects of the different levels of dietary vitamin C on growth, tissue ascorbic acid concentrations and histopathological changes in parrot fish. Casein and gelatin based diets were formulated to contain 0, 60, 120, 240, 480 and 2000mg L-ascorbic acid (AA)kg diets on Ah equivalent basis in the form of L-ascorbyl-2-monophosphate (AMP), 60 and 240 mg AA/kg diet as L-ascorbic acid. Broken line analysis of weight gain indicated that the dietary vitamin C requirement of parrot fish is l18$\pm$12 mg AA/kg diet in the form of L-ascorbyl-2-monophosphate for maximum growth. In experiment II, a 12-week experiment was conducted to compare L-ascorbyl-2-monophosphate-Ca (AMP-Ca) with L-ascorbyl-2-monophosphate-Na/Ca (AMP-Na/Ca) for supplying the dietary vitamin C for juvenile Korean rockfish Sebastes schlegeli. Fish were fed one of 11 semi-purified diets containing equivalent of 0, 50, 100, 200, 400, and 800 mg ascorbic acid (AA)kg diet in the form of AMP-Ca or AMP-Na/Ca for 12 weeks. Broken line analysis of weight gain indicated that the dietary vitamin C requirement of Korean rockfish is 100 mg AA/kg diet in the form of AMP-Na/Ca, and 117 nag AA/kg diet in the form of AMP-Ca. In experiment III, a 12-week experiment was conducted to study the effects of different dietary levels of vitamin C, L-ascorbyl-2-polyphosphate (ASPP), on growth and tissue vitamin C concentrations in juvenile olive flounder. Fish were fed one of six semi-purified diets containing an equivalent of 0, 25, 50, 75, 150, or 1500 mg ascorbic acid (AA) kg 1 diet in the form of ASPP for 12 weeks. Based on broken line analyses for WG and PER, the optimum dietary levels of vitamin C were 91 and 93 mg AA/kg diet, respectively.