• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.60-65
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• 2008

The near-optimal control algorithm for central cooling and heating system has been developed for minimizing energy consumption while maintaining the comfort of indoor thermal environment in terms of the environmental variables such as time varying indoor load and outdoor temperatures. The optimal set-points of control parameters with near-optimal control are supply air and chilled or hot water temperatures. The near optimal control algorithm has been implemented by using LabVIEW program in order to analyze energy performance for central cooling and heating control system.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1285-1288
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• 2007

Au was electrolessly deposited on polycarbonate (PC) membranes (0.1 μm pores) at the air/water interface. It was found that the Au nanotube dimension can be controlled by adjusting the plating temperature and the solution composition. Interfacial deposition of Au at relatively low temperatures (4℃) produced long nanotubes, which run through the whole membrane thickness with small openings. Increase of plating temperatures resulted in the decrease of nanotube lengths and Au film thicknesses. It was also disclosed that the inside-diameter of Au nanotubes can be controlled with negligible variations in length by changing the composition of a plating solution.

• 설비공학논문집
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• 제20권7호
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• pp.470-477
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• 2008

The near-optimal control algorithm for central cooling system has been developed for minimizing energy consumption while maintaining the comfort of indoor thermal environment in terms of the environmental variables such as time varying indoor cooling load and outdoor temperatures. The optimal set-points of control parameters with near-optimal control are supply air and chilled water temperatures. The near optimal control algorithm has been implemented by using LabVIEW program in order to analyze energy performance for central cooling control system.

• The Korean Journal of Ecology
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• 제27권6호
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• pp.369-373
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• 2004

The water strider, Gerris paludum insularis, was reared in a growth cabinet at two constant temperatures and ${\approx}20^{\circ}C$ under a 16:8 (L:D) photoperiod. Differences in head width among three temperatures of ${\approx}20^{\circ}C,\;25^{\circ}C\;and\;30^{\circ}C$ in G. paludum insularis, were compared. Temperature affected growth of head width of G. paludum insularis. There were highly significant differences among head width for three temperature regimes and the immature stages. It was found that head width is greater in $30^{\circ}C$ than $25^{\circ}C\;and\;{\approx}20^{\circ}C$. The growth quantity of the head width in ${\approx}20^{\circ}C$ shows the slowest increase, and $25^{\circ}C\;and\;30^{\circ}C$ were gradually increased in that order. The maximum ratio of growth quantity by each stage is in the first instar in all regimes. The growth rates of all regimes show an increase pattern.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.207-208
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• 2017

The current study assumed a condition in which concrete curing was not completed correctly in the winter, in order to analyze the effect of changes in early low-temperatures in early-frost damage depth. As a result, lower external temperature early on after depositing the concrete greatly reduced the temperature in the upper parts of the concrete, and it delayed the time during which the concrete temperature restored. In addition, for early-frost damages, lower early temperature increased the expansion of frozen water, which in turn relaxes the concrete structures and increases the absorption rate, ultimately extending the depth of early-frost damage.

• Environmental Engineering Research
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• 제10권1호
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• pp.31-37
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• 2005

The selective catalytic experiments using both sulfated/sulfur-free titania and V2O5/TiO2 catalysts have been conducted for NO reduction by NH3 in a packed-bed, down-flow reactor. The sulfated and vanadia loaded titania exhibited higher activity for NO removal than the sulfur-free catalysts, where > 90% NO removal was achieved over the sulfated V2O5/TiO2 catalyst between 280∼500 C. The surface structure of vanadia species on the catalyst surface played a critical role in the high performance of catalysts in which the existence of monomeric/polymeric vanadate is revealed by Raman spectra studies. Water vapor and SO2 were added to the reacting system for the catalyst deactivation tests. At higher temperatures (T ≥ 350 C), little deactivation was observed over the sulfated V2O5/TiO2 catalysts, showing good durability against SO2 and water vapor, which is compared with deactivation at lower temperatures.

• Tribology and Lubricants
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• 제22권3호
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• pp.144-148
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• 2006

The experimental investigation was performed to find the associated changes in characteristics of fretting wear with various water temperatures. The fretting wear tests were carried out using the zirconium alloy tubes and the grids with increasing the water temperature. The tube materials in water of $20^{\circ}C,\;50^{\circ}C\;and\;80^{\circ}C$ were tested with the applied load of 20 N and the relative amplitude of $200{\mu}m$. The worn surfaces were observed by SEM, EDX analysis and 2D surface profiler. As the water temperature increased, the wear volume was decreased, but oxide layer was increased on the worn surface. The abrasive wear mechanism was observed at water temperature of $20^{\circ}C$ and adhesive wear mechanism occurred at water temperature of $50^{\circ}C,\;80^{\circ}C$. As the water temperature increased, surface micro-hardness was decreased, but wear depth and wear width were decreased due to increasing stick phenomenon. Stick regime occurred due to the formation of oxide layer on the worn surface with increasing water temperatures

• 한국작물학회지
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• 제43권1호
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• pp.1-5
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• 1998

Experiments were carried out to find out the optimum water potential, temperature, and duration for the priming of rice seeds, Oryza sativa L. (cv. Ilpumbyeo) for better germination at sub-optimal temperatures. Seeds were primed in 0, -0.2, -0.4, -0.6, -0.8, and -1.0 MPa PEG (polyethylene glycol) solutions at $25^{\circ}C$. The optimum water potential for seed priming, the highest water potential at which rice seeds did not germinate, was -0.6 MPa. To find out optimum priming temperature and duration rice seeds were primed in -0.6 MPa PEG solution and 0 MPa (water as a control) for various durations at 15 and $25^{\circ}C$ and the seeds were germinated at 17, 20, and $25^{\circ}C$. Considering germination rate and speed, the optimum priming time in water (0 MPa) was 4 days at 15$^{\circ}C$ and 1 day at $25^{\circ}C$, while 4 days was the optimum priming time in a -0.6 MPa PEG solution, regardless of the priming temperature. Priming reduced the actual time of germination, especially at sub-optimal temperatures. Priming did not affect germination rate in -0.6 MPa PEG solution at 15$^{\circ}C$, but overpriming reduced the final germination rate in water at 15$^{\circ}C$ and in -0.6 PEG solution at $25^{\circ}C$. Total sugars and $\alpha$-amylase activity induced during the seed priming were negatively correlated with the final germination rate and there was no noted relationship with the speed or uniformity of germination.

• 한국수산과학회지
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• 제36권6호
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• pp.586-590
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• 2003

The effect of water temperature and feed on the growth, survival, and body composition of juvenile abalone (Haliotis discus hannai) fed an artificial formulated diet and a macroalgae (Laminaria japonica) for 12 weeks was investigated. Rearing temperature was maintained at $13{\circ}C,\;16{\circ}C,\;19{\circ}C$ by heated and natural sea water temperatures $(7.5-10.2{\circ}C).$ Shell growth, weight gain, and survival rate of the abalone were affected by water temperature and diet (P<0.05). Survival and growth rate of the abalone fed with the formulated diet and Laminaria at $19{\circ}C$ was significantly higher than those of the abalone fed the formulated diet or Laminaria at $13{\circ}C,\;16{\circ}C,$ and ambient temperatures (P<0.05). Moisture, crude protein, crude lipid, and ash contents of the soft whole body were affected mainly by diet than rearing water temperature (P<0.05). These indicate that a mixture of formulated diet and macroalgae could improve the growth of the abalone independent of water temperature and heated water could improve the growth of abalone during the winter season.

• 대한화학회지
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• 제40권12호
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• pp.748-755
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• 1996

물과 요소 수용액에서 Poly(ethylene oxide)(PEO)의 구조 성질에 대한 온도의 효과를 보고한다. 물과 요소/물 혼합물 (요소 농도는 각각 0.2, 1, 2 M)에서 PEO에 대한 고유점도와 Huggins 계수의 값은 점도측정 방법에 의해 얻어졌으며, 이것을 물 구조 변화 관점에서 논의했다. 낮은 온도(22.deg.C이하)에서 PEO-물간 상호작용은 우세해 사슬은 펼쳐져있는 반면, 높은 온도(24.ang.C 이상)에서는 상호작용이 우세하지 못하고 사슬은 소수성 수화에 의해 어켜있게 된다. 즉, 온도가 상승함에 따라 PEO-물 상호작용은 우세하지 못하게 된다. 요소가 계에 가해짐에 따라 PEO사슬은, 우세하지 못한 PEO-물 상호작용으로부터 유발된 구조화된 물의 동요에 의해, 더 펼쳐지거나 거대해지게 된다. 고유점도 값에 대한 온도의 효과는 Arrhenius 행동을 나타낸다. 따라서 점성 흐름에 대한 활성화 에너지를 구해 논의하였다.