• Journal of Fisheries and Marine Sciences Education
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• v.28 no.3
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• pp.738-745
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• 2016

Aquaculture production of Korean rockfish Sebastes schlegeli has been continuously increased from 2000s and the fish has become the second most important mariculture fish in Korea. However, there are some environmental problems in aquaculture of Korean rockfish recently. In this regards, stress responses to high water temperature was examined via oxygen consumption, blood physiological parameter and endocrinological method. Oxygen consumption of Korean rockfish had significantly increased with rising water temperature. And oxygen consumption during the light time was no different with the dark time. The levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) showed no difference until $27^{\circ}C$, but it had rapidly increased at $30^{\circ}C$. Moreover high water temperature affected to increase in plasma glucose and cortisol levels.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.761-766
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• 2006

This paper describes a study on the performance of steam ejector by variation of steam pressure. Water temperature is especially important for good qualify of fish in an inland aquafam. In summer season, the water temperature increases above $25^{\circ}C$, but for good quality breeding or fish is the maintenance of optimum aquafam temperature by about $20^{\circ}C$. Therefore it is needed to drop the water temperature to provide suitable conditions of fish growth. There are many kinds of cooling system, in this study using steam ejector. After cooling the water in vacuum tank with the steam ejector then circulate this water to inland aquafam. In this way to minimizes fish stress that it is caused by water temperature. The objective of research confirms the difference of the case which there is no water in the vacuum tank and has water in the vacuum tank. The purpose of this paper is to examine the effects on the performance of steam ejector by variation of steam pressure.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.467-468
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• 2005

Low cycle fatigue test results of Type 316 stainless steel in $310^{\circ}C$ water environment can be summarized as follows. 1. Cyclic stress response of Type 316 stainless steel shows negative strain rate sensitivity, primary hardening and secondary hardening. 2. Fatigue life in $310^{\circ}C$ water environment was shorter than fatigue life in room temperature air environment. This was because of water environment and temperature effects.

• Journal of Applied Reliability
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• v.11 no.3
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• pp.281-291
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• 2011

This paper presents an accelerated life test of booster pump for home water purifier. The failure analysis shows that decreased flux due to the plastic deformation of bypass spring adjusting pressure is the predominant failure mechanism. An accelerated life test is designed and implemented to estimate the lifetime of the booster pump. Temperature, water pressure and voltage are selected as accelerating variables through the technical review about failure mechanism. It is assumed that the lifetimes of booster pumps follow lognormal distribution and the combination model of temperature and non-thermal stresses holds. The life-stress relationship, acceleration factor, and $B_{10}$ life at design condition are estimated by analyzing the accelerated life test data.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.20-27
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• 2020

The study was performed to calculate canopy temperatures and crop water stress index (CWSI) of 2-year-old 'Yumi' peach trees using thermal infrared imaging under different soil water conditions, and to evaluate availability for water stress determination. Canopy temperatures showed similar daily variations to air temperatures and they were higher during the daytime than air temperatures. Canopy temperatures for 24 h were correlated highly to air temperatures (r² =0.95), solar radiations (r² =0.74), and relative humidity (r² =-0.88). In addition, soil water potential showed a highly negative correlation to canopy temperatures (r² =-0.57), temperature differences between leaf and air (TD) (r² =-0.71), and CWSI (r² =-0.72) during the daytime (11 to 16 h). CWSI for 24 h was highly related to canopy temperatures (r² =0.90) and TD (r² =0.92), whereas CWSI was not correlated to soil water potential (r² =-0.27) for 24 h but related highly to water potential (r² =-0.72) during the daytime (11 to 16 h). Correlation coefficients between CWSI (y) and soil water potential (x) were highest from 11 to 12 h and a regression equation was deduced as y = -0.0087x + 0.14. CWSI was calculated as 0.575 at -50 kPa, which soil water stress generally occurs. Thus our result suggests that this regression equation using thermal infrared imaging is useful to evaluate soil water stress of peach trees.

• Journal of the Korean Geosynthetics Society
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• v.5 no.3
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• pp.31-36
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• 2006

In this study, stress relaxation behaviors of nonwoven geotextile and geomembrane which have protection, filtration and drainage, water barrier functions, respectively were examined. 'Theory of transition phenomen' was applied to interpretate the stress relaxation behaviors of two geosynthetics. The initial and later relaxation times for stress relaxation behaviors of geosynthetics were derived from the constitutive equations. The initial relaxation behaviors of these geosynthetics were dependent on the additional strains and were especially faster with temperature. Finally, both relaxation times of geosynthetics were shorter with additional strain and temperature and the reduction of relaxation times of nonwoven geotextile were larger than those of geomembrane.

• Journal of the Korean Geosynthetics Society
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• v.3 no.4
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• pp.21-27
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• 2004

Stress relaxation behaviors of nonwoven geotextile and geomembrane which have protection, filtration and drainage, water barrier functions, respectively were analyzed. 'Theory of transition phenomena' was applied to interpretate the stress relaxation behaviors of two geosynthetics. The initial and later relaxation times for stress relaxation behaviors of geosynthetics were derived from the constitutive equations. The initial relaxation behaviors of these geosynthetics were dependent on the additional strains and were especially faster with temperature. Finally, both relaxation times of geosynthetics were shorter with additional strain and temperature.

• Journal of Korean Society of Forest Science
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• v.55 no.1
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• pp.55-58
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• 1982

This study is to investigate the effects of temperature, light and water deficit on apparent phytosynthesis rate (Pn) and dark respiration rate(Rd) of leaves in the series of studies dealing with primary productivity of korean white pine forest. The results obtained are as follows: 1. The light saturation for Pn occured at about 40 Klux, and light compensation at 1.0 to 1.3 Klux. 2. The Pn of current leaves was highest, and Pn was decreased with increasing leaf age. 3. The Rd on the response of temperature in February was about two times value in all of the temperature ranges as compared with the ones in August. 4. The incipient water stress, above which Pn and Rd declined from 100%, was different for Pn(-10bar). The high water stress required to reduce Pn to nearly 0%, at -24 bar, but Rd was only 43% at -24 bar. 5. The optimum temperature range for Pn showed about 15 to $18^{\circ}C$ in February and 23 to $26^{\circ}C$ in August.

• Ocean and Polar Research
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• v.35 no.2
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• pp.85-92
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• 2013

The coral symbiotic algae zooxanthellae is often expelled from the host as the host coral is under physiological stress, causing the coral to turn completely white. Such coral bleaching events are occurring more frequently with the increase in the global warming, ocean acidification and increased level of anthropogenic impacts such as eutrophication. In the present study, we investigated the effects of inorganic nutrients including ammonium, nitrate, phosphate and elevated water temperature on the symbiotic zooxanthellae density in the fragment of branching coral Acropora nobilis. Zooxanthellae density in the host coral decreased 8 hrs after the experiment at a given elevated water temperature ($32^{\circ}C$, p < 0.05). In contrast, no clear coral bleaching or decrease in the symbiotic algae density was observed from the branching coral exposed to a normal water temperature of $30^{\circ}C$ and high levels of nutrients such as 20 ${\mu}M$ of $NH_4Cl$, 20 ${\mu}M$ of $NaNO_3$ and, 10 ${\mu}M$ $KH_2PO_4$. Accordingly, the data indicated high water temperature is one of the stressful factors to cause bleaching in A. nobilis, whereas the high levels of nutrients is not a factor. It is believed that the results obtained in the present study are useful as baseline information in the management of the coral reefs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.118-122
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• 2006

This experiment was carried out on plastic pots ($40cm{\times}25cm{\times}30cm$) filled with sand soil at greenhouse using two soybean cultivars with small seed; one was Pungsannamulkong (PSNK) recognized as a tolerant cultivar against excessive water stress and the other one was Sobaeknamulkong (SBNK) recognized as a susceptible cultivar. Seed was sown with 30 plants of 2 hills, and the amount of applied fertilizer was N; 3.0 g, P; 3.0 g, and K; 3.4 g per $m^2$ with all basal fertilizations. Plants were grown under photoperiod of natural light with day temperature of $31{\pm}5^{\circ}C$ and night temperature of $22{\pm}1^{\circ}C$. The flooding treatment was done for 3, 5, 7 and 10 days by filling pots with tap water up to 1 cm above the level of the soil surface when plants were 2 days after emerging. Nitrogen uptake by leaves of soybeans decreased significantly by the flooding after 6 days. This significant reduction of N uptake by flooding was evidently recognized from the chlorosis of leaves. The dry matter of flooded soybean seedlings significantly decreased compared to non-flooded soybean seedlings at 10 days. The dry matter of roots also showed similar result of the shoot. Shoots had more N reduction than roots under the flooding. This N reduction was more pronounce in SBNK than in PSNK. Chlorophyll content of flooded soybeans showed decreasing or non-increasing tendency, and the reduction of chlorophyll content was more in SBNK than in PSNK from the flooding stress. Nitrate content of soybean seedlings with flooding stress showed decreasing tendency in shoot and root parts. Ammonium content, however, was higher in flooding stress compared to the non-flooding. Flooding caused a remarkable change in the AA (amino acid) composition and TAA (total amino acid) concentration in the leaves of soybean seedlings.