• Fisheries and Aquatic Sciences
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• 제6권2호
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• pp.59-65
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• 2003

The critical thermal maximum (CTM) of black rockfish, Sebastes schlegeli, was evaluated. Black rockfish were acclimated at $24^{\circ}C$, and then exposed to temperatures from 24 to $33^{\circ}C$. Black rockfish were kept in constant darkness and subjected to a gradual temperature increase $(1 ^{\circ}C\;12^{-1})$. The oxygen consumption rate (OCR) was measured using an automatic intermittent­flow-respirometer (AIFR) during the exposure period (from 119.3 to 143.5 h). The OCR increased from 94.5 to 214.2mL $O_2 kg^{-1}\;ww\;h^{-1}$ as the temperature rose from 24 to $29.4-30.9^{\circ}C$. Subsequently, the OCR increased abruptly, reaching 245.8-412.7mL $O_2 kg^{-1}\;ww\;h^{-1}$ at $32^{\circ}C$. This study suggests that the CTM for black rockfish is $29.4-30.9^{\circ}C$ when temperature is increased at $1^{\circ}C\;12h^{-1}$ following acclimation at $24^{\circ}C$.

• 열처리공학회지
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• 제24권4호
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• pp.187-192
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• 2011

Effect of austenitizing temperatures on the impact value of the AISI 4140 steel after repetition of spheroidization and cold deep drawing treatment has been studied. Sufficient dissolution of carbide was shown after austenitizing at the high temperature of $950^{\circ}C$. Accordingly, the impact value was remarkably increased by tempering of this high temperature austenitized steel at the tempering temperature ranges between $570^{\circ}C$ and $630^{\circ}C$. On the other hand, remarkable decrease in the impact values and elongations were shown by tempering the low temperature-austenitized ($870^{\circ}C$) steel due to the coarsening of undissolved-carbide existed at the austenitizing temperature.

• 한국어병학회지
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• 제2권2호
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• pp.99-108
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• 1989

마취제는 어류를 취급할 때 특히, 수송, 표지작업, 선별작업에 필요하다. 마취제 중에서 MS-222는 뛰어난 효과로 인해 양식사업에 널리 이용되고 있다. 그러나 MS-222는 마취제보다 가격이 비싸 경제적인 것이 못된다. Benzocaine(Ethyl-p-aminobenzoate)은 MS-222와 거의 동등한 마취효과를 지니고 있으며 가격이 저렴하여 경제적이다. 본 연구에서는 tilapia 선별을 위해 Benzocaine을 사용하여 환경 변화중 수온과 pH변화에 따른 마취 및 회복 효과를 실험 했으며 실제 양어장에서의 제반 여건을 고려하여 직접 응용할 수 있는 방안을 제시하여 목적에 따라 경제적으로 사용할 수 있도록 하는 것이다. 그 결과는 다음과 같다. 1. pH 변화에 따른 마취 효과는 pH가 낮을수록 명확하게 안정되었다. 2. 어체중 변화에 따른 마취 효과의 유의성은 거의 인정되지 않았다. 3. 실제 양어장의 환경 여건을 감안한 50ppm Benzocaine의 마취 시간은 4~10분 이었고 회복 시간을 마취를 30분 지속시킨 후의 경우 4~6분 소요 되었다. 4. Benzocaine은 수온 변화보다 pH 변화에 더 민감하게 작용했다. 5. Benzocaine의 24시간-TLm은 수은 $24^{\circ}C$, pH 6.8에서 50ppm마취액에 120분간 지속시킨 후 24시간 후에 50% 생존율을 나타냈다.

• 환경생물
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• 제17권2호
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• pp.209-215
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• 1999

온도, pH및 염도 stress가 굴(Crassostrea gigas)의 malate dehydrogenase isozyme에 미치는 영향을 전기영동법으로 분석하였다. 대조군의 MDH isozyme은 2개의 band가 양극 쪽으로 이동되어 분리되었다. 각 실험 온도와 pH를 12시간 노출시킨 실험군에서는 1개의 band만 양극 쪽에서 분리되었고, 24시간과 48시간 노출한 실험군에서는 2개의 band가 모두 양극 쪽에서 분리되었다. 염분 농도가 5ppt 와 3ppt에서 12시간 노출시켰을 때 각각 2개의 band가, 10ppt와 40ppt에서는 각각 3개의 band가 분리되었고, 24시간과 48시간 노출 실험군에서는 2개의 band가 양극 쪽에서 분리되었다. 모든 isozyme pattern에서 각 band의 활성도는 실험 조건에 따라 각각의 특이성이 나타났다. 결과적으로 MDH isozyme의 변화는 굴이 환경 stress에 대한 생화학적 반응의 결과로 간주된다.

• 소성∙가공
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• 제24권4호
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• pp.248-255
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• 2015

The warm drawing of magnesium alloy AZ31B sheet is affected by temperature because tensile elongation is changed due to the elevated temperature. In the current study, the effect of temperature was investigated for an automotive dash panel part by both experimental and FE analysis. Tensile tests were performed to obtain mechanical properties for various temperatures. AZ31B alloy sheet shows increased total elongation with increasing deformation temperature in the range of 200 to 300℃. The heating channel inserted into the die was used to regulate and to obtain an optimal temperature. A temperature controller was constructed to reduce temperature variation. Warm drawing of magnesium alloy AZ31B was performed to produce the desired shape of the lightweight automotive dash panel. The simulated results showed good agreement with the experimental results.

• Applied Science and Convergence Technology
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• 제24권6호
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• pp.262-267
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• 2015

We demonstrate the growth of single-walled carbon nanotubes (SWNTs) using ethylene-based chemical vapor deposition (CVD) and ferritin-induced catalytic particles toward growth temperature reduction. We first optimized the gas composition of $H_2$ and $C_2H_4$ at 500 and 30 sccm, respectively. On a planar $SiO_2$ substrate, high density SWNTs were grown at a minimum temperature of $760^{\circ}C$. In the case of growth using nanoporous templates, many suspended SWNTs were also observed from the samples grown at $760^{\circ}C$; low values of $I_D/I_G$ in the Raman spectra were also obtained. This means that the temperature of $760^{\circ}C$ is sufficient for SWNT growth in ethylene-based CVD and that ethylene is more effective that methane for low temperature growth. Our results provide a recipe for low temperature growth of SWNT; such growth is crucial for SWNT-based applications.

• 한국분말재료학회지
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• 제24권1호
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• pp.41-45
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• 2017

The effects of the heat treatment temperature and of the atmosphere on the dehydrogenation and hydrogen reduction of ball-milled $TiH_2-WO_3$ powder mixtures are investigated for the synthesis of Ti-W powders with controlled microstructure. Homogeneously mixed powders with refined $TiH_2$ particles are successfully prepared by ball milling for 24h. X-ray diffraction (XRD) analyses show that the powder mixture heat-treated in Ar atmosphere is composed of Ti, $Ti_2O$, and W phases, regardless of the heat treatment temperature. However, XRD results for the powder mixture, heat-treated at $600^{\circ}C$ in a hydrogen atmosphere, show $TiH_2$ and TiH peaks as well as reaction phase peaks of Ti oxides and W, while the powder mixture heat-treated at $900^{\circ}C$ exhibits only XRD peaks attributed to Ti oxides and W. The formation behavior of the reaction phases that are dependent on the heat treatment temperature and on the atmosphere is explained by thermodynamic considerations for the dehydrogenation reaction of $TiH_2$, the hydrogen reduction of $WO_3$ and the partial oxidation of dehydrogenated Ti.

• 한국작물학회지
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• 제24권2호
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• pp.35-41
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• 1979

To observe the effects of temperature and photoperiod on the growth and yield of winter wheat (Triticum aestivum, L) eight varieties including Chang Kwang were tested at various treatments like longday-high temperature (24hrs-20\circ), shortdayhigh temperature (12hrs-20\circ), longday-low temperature (24hrs-14\circ) and shortday-low temperature (12hrs-14\circ). Among the traits measured, days to heading, plant height, spike length, number of spikes per hill and grain yield per hill were generally decreased at high temperature and long day treatment and increased at low temperature and shortday condition. Number of grains per spike was decreased at low temperature and short day condition while increased at longday and high temperature conditions. Grain weight was decreased significantly at high temperature and shortday while increased at low temperature and longday treatment.

• 한국초전도ㆍ저온공학회논문지
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• 제24권3호
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• pp.41-46
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• 2022

The superconducting properties of high temperature superconducting (HTS) GdBCO coated conductor (CC) tape (Ag/GdBCO/Buffer-layers/Stainless Steel) were investigated, specifically a series of samples prepared by vacuum heat treatment (200℃ to 600℃), using a Quantum Design PPMS-14. The critical current density J_c value was obtained by applying the modified Bean model to the irreversible magnetization ∆M_irr(H) data which was estimated from the magnetization M(H) loop. The reduction rates of lnJ_c and T_c values according to the increase of the vacuum annealing temperature T_an were d(lnJ_c)/dT_an = - 0.016 A/(cm²∙℃) and dT_c/dT_an = - 0.24, respectively. We examined the effect of recovery temperature T_re (475℃ to 700℃) and recovery duration time t (0.5 h to 24 h) on the restoration of previously completely lost superconductivity in samples that subsequently received heat treatment in an O₂ gas flow space. All samples were fully restored to superconductivity by heat treatment in an O₂ gas flow space. The recovery temperatures T_re (475℃ to 700℃) and recovery duration times t (0.5 h to 24 h) were both independent of the superconductivity recovery characteristics.

• Fisheries and Aquatic Sciences
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• 제24권2호
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• pp.99-107
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• 2021

Water temperature (WT) is a major environmental factor of metabolic rate in fish; it directly affects food intake, ammonia excretion, oxygen consumption (OC), growth, and survival. Thus, the purpose of this study was to investigate changes in the OC and the hematological response of olive flounder Paralichthys olivaceus because of WT changes. In Exp. I, WT was increased from 20℃ to 29℃ within 18 h and maintained at 29℃ for 96 h. Then, WT was decreased from 29℃ to 20℃ within 18 h and maintained at 20℃ for 24 h. In Exp. II, WT was decreased from 20℃ to 11℃ within 18 h and maintained at 11℃ for 96 h. Then, WT was increased from 11℃ to 20℃ within 18 h and maintained at 20℃ for 24 h. The Exp. III maintained that the Exp. I and II was consecutively. In Exp. I, the OC increased from 116.7 mg O₂ kg^-1 hr^-1 to 317.5 mg O₂ kg^-1 hr^-1 with increasing WT. In Exp. II, the OC decreased from 96.5 mg O₂ kg^-1 hr^-1 to 71.3 mg O₂ kg^-1 hr^-1 with decreasing WT. In Exp. III, OC tended to increase or decrease in inverse proportion to temperature. In Exp. I, cortisol, glucose, and aspartate aminotransferase (AST) values increased with increasing WT. In Exp. II, Cl^-, osmolality, AST, and alanine aminotransferase (ALT) values significantly changed during the experimental period: glucose values increased, whereas cortisol values decreased with decreasing WT. Exp. III was shown to be a more stressful environment to olive flounder than Exp. I and Exp. II. The results of our study will be useful for evaluating current aquaculture procedures of olive flounder and developing techniques to minimize stress in aquaculture farms.