• Asian-Australasian Journal of Animal Sciences
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• v.27 no.5
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• pp.690-699
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• 2014

Three feeding trials were conducted to evaluate the effects of feeding rate and water temperature on growth and body composition of juvenile Korean rockfish, Sebastes schlegeli rearing at 3 different water temperatures. A total of 270 fish (each experiment) individual body weight (BW) averaging $16{\pm}0.3g$ ($mean{\pm}SD$) were fed a commercial diet for 4 wk at $16^{\circ}C$, $20^{\circ}C$, and $24^{\circ}C$. At each temperature, triplicate tanks were assigned to one of 6 feeding rates: 1.5%, 2.5%, 2.8%, 3.1%, 3.4%, and satiation (3.7% BW/d) at $16^{\circ}C$, 1.9%, 2.9%, 3.2%, 3.5%, 3.8% and satiation (4.1% BW/d) at $20^{\circ}C$ and 1.7%, 2.7%, 3.0%, 3.3%, 3.6%, and satiation (3.9% BW/d) at $24^{\circ}C$ water temperature. Weight gains of fish in satiation and 3.4% groups at $16^{\circ}C$, in satiation and 3.8% groups at $20^{\circ}C$ and in satiation and 3.6% groups at $24^{\circ}C$ were significantly higher than those of fish in the other treatments (p<0.05). A broken line regression analysis of weight gain indicated that optimum feeding rates of juvenile Korean rockfish were 3.41% at $16^{\circ}C$, 3.75% at $20^{\circ}C$ and 3.34% at $24^{\circ}C$ water temperature. Results of the present study indicate that the optimum feeding rate could be >3.1% but <3.41% at $16^{\circ}C$, >3.5% but <3.75% at $20^{\circ}C$ and >3.0% but <3.34% at $24^{\circ}C$. As we expected results suggest that fish performed better at $20^{\circ}C$ than $16^{\circ}C$ or $24^{\circ}C$ water temperature and the optimum feeding rate could be 3.1% BW/d to 3.7% BW/d in 16 g of juvenile Korean rockfish.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.3
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• pp.186-194
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• 1994

Lack of seedling vigor is considered a serious deterrent to use of broadleafed birdsfoot trefoil (Lorus comicul~rus L.). Our objectives were to compare early seedling growth of broadleafed birdsfoot trefoil cultivar "MO-20" and the large-seeded accession 302921 at $15^{\circ}C$ and $25^{\circ}C$. in controlled-environment chambers. Cabon dioxide exchange rate (CER) was measured in a closed or open system using infrared gas analysis. Dark respiration rate was measured manometrically. Net carbon accumulated per day and growth analysis of the seedlings were calculated. Initial seed mass of 302921 was 3.5 times larger and final cotyledon area was 2 times larger than those of MO-20, and early seedling growth was better. But, from 3 weeks after emergence until the end of the test period at $25^{\circ}C$, MO-20 showed higher CER per unit leaf area and faster dry weight accumulation than did 302921. Compared with $25^{\circ}C$, growth of MO-20 at $15^{\circ}C$ was suppressed more than that of 302921. Dark respiration rate of MO-20 was slightly higher than that for 302921, but not COz uptake per day for MO-20 was highest at$25^{\circ}C$ and lowest at $25^{\circ}C$. The relative growth rate (RGR) of MO-20 was higher than 302921 at $25^{\circ}C$ due to high net assimilation rate, but there was little difference in RGR between entries at $15^{\circ}C$.}C$.

• Journal of Environmental Science International
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• v.22 no.1
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• pp.1-6
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• 2013

A fixed biofilm reactor system composed of anaerobic, anoxic(1), anoxic(2), aerobic(1) and aerobic(2) reactor was packed with synthetic activated ceramic (SAC) media and adopted to reduce the inhibition effect of low temperature on nitrification activities. The changes of nitrification activity at different wastewater temperature were investigated through the evaluation of temperature coefficient, volatile attached solid (VAS), specific nitrification rate and alkalinity consumption. Operating temperature was varied from 20 to $5^{\circ}C$. In this biofilm system, the specific nitrification rates of $15^{\circ}C$, $10^{\circ}C$ and $5^{\circ}C$ were 0.972, 0.859 and 0.613 when the specific nitrification rate of $20^{\circ}C$ was assumed to 1.00. Moreover the nitrification activity was also observed at $5^{\circ}C$ which is lower temperature than the critical temperature condition for the microorganism of activated sludge system. The specific amount of volatile attached solid (VAS) on media was maintained the range of 13.6-12.5 mg VAS/g media at $20{\sim}10^{\circ}C$. As the temperature was downed to $5^{\circ}C$, VAS was rapidly decreased to 10.9 mg VAS/g media and effluent suspended solids was increased from 3.2 mg/L to 12.0 mg/L due to the detachment of microorganism from SAC media. And alkalinity consumption was lower than theoretical value with 5.23 mg as $CaCO_3$/mg ${NH_4}^+$-N removal at $20^{\circ}C$. Temperature coefficient (${\Theta}$) of nitrification rate ($20^{\circ}C{\sim}5^{\circ}C$) was 1.033. Therefore, this fixed film nitrogen removal process showed superior stability for low temperature condition than conventional suspended growth process.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.779-784
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• 1998

The specific growth rate and production of resting ega of the freshwater rotifer, Brachionus calyciflorus Pallas was investigated at the different temperatures ($20\~30^{\circ}C$). The rotifer was cultured in 250 ml flask and fed on concentrated freshwater Chlorella. Specific growth rate of B. calyciflorus showed higher rate at higher temperature, but maximum density was observed higher at lower temperature, expect at $20^{\circ}C$. The production of resting egg with temperature was showed decrease on the basis on $26^{\circ}C$. The highest number of resting egg per ml and rotifer $10^4$ were 157 eggs and 810 eggs at $26^{\circ}C$, respectively. This result shows that the optimum temperature for mass culture and resting egg production of this freshwater rotifer were $30^{\circ}C$ and $26^{\circ}C$, respectively.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.44-44
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• 2019

Spring sowing of ginseng seeds often results in failure of seedling establishment. Storage condition during winter, sowing time, and seed treatment might effect on germination. Here we tested effects of temperature regimes of seed storage on spring sowing. Dehisced wet or dry ginseng seeds were stored at $2^{\circ}C$, $-2^{\circ}C$, $-3.5^{\circ}C$, or alternating temperature: at $2^{\circ}C$ until December, $-3.5^{\circ}C$ in January, and $2^{\circ}C$ in February, and sowed in March. In overall, emergence rate was dependent on storage temperature, and $-3.5^{\circ}C$ resulted poorest emergence than other conditions. Storage of wet seeds in alternating temperature resulted highest emergence rate. Seed dry also affected on emergence rate, while it was dependent on the storage temperature. In terms of growth, storage at $2^{\circ}C$ as wet seed resulted highest growth, and dried seeds resulted poorer growth than wet seeds. As a modification of alternating temperature, seeds were stored at $2^{\circ}C$ at first, then transferred to $-3.5^{\circ}C$ at Nov 30, Dec 20, and Jan 10, each. When transfer date was delayed, emergence rate was increased. We suggest that seed storage temperature for ginseng should not be decreased below $-2^{\circ}C$, and alternative temperature regime for successful spring sowing could be useful.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.2
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• pp.152-156
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• 1984

Germination and emergence of 16 barley cultivars bred in Korea were studied under different low temperature conditions in laboratory at Suweon. This study revealed that the barley cultivars differed markedly in their germination rate index (GRI), emergence rate index (ERI), and dry matter weight. The seeds of Baekdong, Namhaebori, Gangbori and Buheung germinated better than others in $4^{\circ}C$ plot. Yeongsanbori, Kwangseong and Baekdong had very poor ERI values, but Buhobori, Namhaebori, Oweolbori, Albori and malting barley, Sacheon 6 had very good ERI values. Germination rate index were not correlated with emergence rate index under any temperature conditions. The correlation coefficient between ERI of $4^{\circ}C$ and $7^{\circ}C$ plots was very high. Those results showed that for screening the varieties or lines with good emergence capacity under low temperature conditions ERI, FS and dry matter weight would be available.

• Journal of Korea Foundry Society
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• v.17 no.4
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• pp.347-355
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• 1997

It is well known that the coarse primary Si in hypereutectic Al-Si alloys deteriorate castability, machinability, and mechanical properties. So, many treatment has been tried to refine the primary Si increasing cooling rate and adding refinement agent. Therefore. the purpose of our work was the observation of the effect on the refinement of primary Si and the analysis of the trend to apply to the casting process by changing the amount of P addition and the cooling rate while fixing the temperature at $750^{\circ}C$ of P addition and the type of AlCuP. In the condition of amount of P addition was fixed, primary Si was finer as cooling rate increased but in case of cooling rate was fixed, the effect of refinement was resisted as incersed the amount of P addition. At a relatively slow cooling rate of $22^{\circ}C/sec$, refinement was governed by the amount of P addition rather than cooling rate. At elevated cooling rate of $51^{\circ}C/sec$ and $99^{\circ}C/sec$, the undercooling due to faster cooling rate promoted nucleation of primary Si rather than P addition more significantly.

• Food Science and Preservation
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• v.12 no.6
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• pp.529-533
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• 2005

The respiratory characteristics of Korean fresh ginseng were investigated from the aspect of picking season, size, and storage temperature and period to get basic data for extension of shelf-life. The respiration rate of fresh ginseng picked in March was 4.09 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$. It was gradually increased to August, 7.88 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$, and then decreased continuously until November. Although the rate of fresh ginseng was different by picking season, the respiration quotient showed the same level, $1.03\~1.07$. Respiration rate by size was ranged from 3.47 to 5.69 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$, and smaller in the size was higher in the rate. $Q_{10}$ value of fresh ginseng was $2.68\~2.88$ when the temperature increased from $0^{\circ}C\;to\;10^{\circ}C$ and $1.77\~2.16$ from $10^{\circ}C\;to\;20^{\circ}C$, and it was slightly different by picking season. At the beginning of storage the respiration rate was 7.0 mL $CO_2/kg{\cdot}hr$ and it was .decreased to 3.38 mL $CO_2/kg{\cdot}hr$ after storage for 90 days at $0^{\circ}C$.

• Journal of Powder Materials
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• v.17 no.1
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• pp.13-22
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• 2010

The unique features of spark plasma sintering process are the possibilities of a very fast heating rate and a short holding time to obtain fully dense materials. $\beta$-SiC powder with 0, 2, 6, 10 wt% of $\alpha$-SiC particles (seeds) and 4 wt% of Al-B-C (sintering aids) were spark plasma sintered at $1700-1850^{\circ}C$ for 10 min. The heating rate, applied pressure and sintering atmosphere were kept at $100^{\circ}C/min$, 40 MPa and a flowing Ar gas (500 CC/min). Microstructural development of SiC as function of seed content and temperature during spark plasma sintering was investigated quantitatively and statistically using image analysis. Quantitative image analyses on the sintered SiC ceramics were conducted on the grain size, aspect ratio and grain size distribution of SiC. The microstructure of SiC sintered up to $1700^{\circ}C$ consisted of equiaxed grains. In contrast, the growth of large elongated SiC grains in small matrix grains was shown in sintered bodies at $1750^{\circ}C$ and the plate-like grains interlocking microstructure had been developed by increasing sintering temperature. The introduction of $\alpha$-SiC seeds into $\beta$-SiC accelerated the grain growth of elongated grains during sintering, resulting in the plate-like grains interlocking microstructure. In the $\alpha$-SiC seeds added in $\beta$-SiC, the rate of grain growth decreased with $\alpha$-SiC seed content, however, bulk density and aspect ratio of grains in sintered body increased.

• The Korean Journal of Malacology
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• v.26 no.2
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• pp.157-163
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• 2010

This study was carried out to investigate the toxic effect of WSF (Water Soluble Fraction) on development time, development rate, attachment rate, survival rate and growth of the larvae during the early life stage of the abalone, Haliotis discus hannai. Also, observed effect of water temperature on the survival rate and histological change of gill in the early young shell. In the abalone, it takes around 12 hours in all experimental groups. Development and attachment rate of the abalone significantly lower more than 0.4 mg/L WSF compared to control group (P < 0.05). Survival rate of abalone larva and spot was significantly lower more than 0.4 mg/L and 2.4 mg/L WSF compared to control group, respectively (P < 0.05). Shell growth of the abalone were significantly lower more than 2.4 mg/L WSF compared control group (P < 0.05). Survival rate lower more than $25^{\circ}C$ exposure group compared water temperature $17^{\circ}C$ exposure group in the early young shell. The gill of abalone exposed water temperature $17^{\circ}C$ and $25^{\circ}C$ was showed atrophy of nucleus and breakdown of the filament, vacuolation of filament epithelial cell.