• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.35-38
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• 2003

The purpose of this study is to investigate the manufacture of light weight concrete panel using the artificial light-weight aggregate as a part of the substitution of foamed styrene and polyurethane because of narrow allocable temperature Bone in use. The experimental parameter of this study is 40, 60 and 8$0^{\circ}C$ of curing temperature at 100% relative humidity and the type of admixture such as cement, 6mm glass fiber and St/BA emulsion. Testing item is compressive and flexural strength and strength of specimen cured at standard condition is compared to that of specimen cured at 40, 60 and 8$0^{\circ}C$ of curing temperature at 100% relative humidity. As a result or this, it was revealed that the maximum or strength is developed in 6$0^{\circ}C$ or cure temperature at 100% relative humidity in case of the most of the specimen. Specimens modified by St/BA emulsion show the highest development of strength dependent on the curing tmeperature. So, it seems to be effective that evaporation curing method shoud be considered to curing the specimen as the panel core.

• 한국응용곤충학회지
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• 제50권4호
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• pp.343-352
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• 2011

줄무늬잎마름병을 매개하는 애멸구, Laodelphax striatellus Fallen의 온도에 따른 알 및 약충 발육 기간을 12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, $35{\pm}1^{\circ}C$의 10개 항온, 14:10 (L:D) h 광, 상대습도 30~40% 조건에서 조사하였다. 알은 모든 온도 조건에서 1령으로 성공적으로 발육하였으며, 발육기간은 $12.5^{\circ}C$에서 44.5일로 가장 길었고 온도가 증가함에 따라 짧아져 $35^{\circ}C$에서 5.8일로 가장 짧았다. 약충은 12.5, 15, 17.5, 20, 22.5, 25, 27.5, $30^{\circ}C$에서 성충까지 발육 가능하였으며, 각 온도에서 약충 전체 발육기간은 132.7, 55.9, 37.7, 26.9, 20.2, 15.8, 14.9, 17.4일이 소요되었다. 온도와 발육율과의 관계를 설명하기 위해 선형 및 4개의 비선형 (Briere 1, Lactin 2, Logan 6, Poikilotherm rate) 모델을 사용하여 분석하였다. 선형 모델을 이용하여 추정한 알과 약충 전체기간 발육을 위한 발육영점온도는 각각 $10.2^{\circ}C$와 $10.7^{\circ}C$였으며 발육에 필요한 유효적산온도는 각각 122.0, 238.1DD였다. 4가지 비선형 모델 중 Poikilotherm rate 모델이 모든 발육단계에서 온도와 발육율과의 관계를 가장 잘 설명하였다 ($r^2$=0.98~0.99). 알 및 유충의 발육단계별 발육완료 분포는 two-parameter Weibull 함수를 사용하였으며 모든 발육단계에서 비교적 높은 상관관계 ($r^2$=0.84~0.94) 값을 보여 양호한 모형 적합성을 보였다. DYMEX$^{(R)}$(version 3.0)를 이용하여 2개 지역에서 애멸구 월동 개체군의 발육을 추정한 결과 월동 후 개체군의 생리적 연령을 0.2로 가정하고 온도발육 모델로 Poikilotherm rate 모델을 사용하였을 경우 높은 우화시기 예측력을 볼 수 있었다.

• Computers and Concrete
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• 제21권3호
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• pp.279-289
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• 2018

Hydration heat and thermal induced cracking have always been a fatal problem for massive concrete structures. In order to study a massive reinforced concrete wall of a storage tank for liquefied natural gas (LNG) during its construction, two mock-ups of $0.8m{\times}0.8m{\times}0.8m$ without and with metal corrugated pipes were designed based on the actual wall construction plan. Temperature distribution and strain development of both mock-ups were measured and compared inside and on the surface of them. Meanwhile, time-dependent thermal and mechanical properties of the concrete were tested standardly and introduced into the finite-element (FE) software with a proposed hydration degree model. According to the comparison results, the FE simulation of temperature field agreed well with the measured data. Besides, the maximum temperature rise was slightly higher and the shrinkage was generally larger in the mock-up without pipes, indicating that corrugated pipes could reduce concrete temperature and decrease shrinkage of surrounding concrete. In addition, the cooling rate decreased approximately linearly with the reduction of heat transfer coefficient h, implying that a target cooling curve can be achieved by calculating a desired coefficient h. Moreover, the maximum cooling rate did not necessarily decrease with the extension of demoulding time. It is better to remove the formwork at least after 116 hours after concrete casting, which promises lower risk of thermal cracking of early-age concrete.

• 대한조선학회논문집
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• 제59권3호
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• pp.157-163
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• 2022

An automatic mooring system for a ship consists of a vacuum suction pad and a mechanical part, enabling quick and safe mooring of a ship. In the development of a mooring system, the design of a vacuum suction pad is a key to secure enough mooring forces and achieve stable operation of a mooring system. In the vacuum suction pad, properly designing its rubber seal determines the performance of the suction pad. Therefore, it is necessary to appropriately design the rubber seal for maintaining a high-vacuum condition inside the pad as well as achieving its mechanical robustness for long-time use. Finite element analysis for the design of the rubber seal requires the use of an appropriate strain energy function model to accurately simulate mechanical behavior of the rubber seal material. In this study, we conducted simple uniaxial tensile testing of Chloroprene Rubber (CR) to explore the strain energy function model best-fitted to its experimentally measured engineering strain-stress curves depending on various temperature environments. This study elucidates the temperature-dependent mechanical behaviors of CR and will be foundational to design rubber seal for an automatic mooring system under various temperature conditions.

• 한국분말재료학회지
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• 제11권6호
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• pp.503-509
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• 2004

Dispersion stabilities and photocatalytic activities of rutile $TiO_{2}$ powders with unique nano-structure synthesized by homogeneous precipitation process at low temperature(HPPLT) have been investigated in the acrylic resin containing fluorostyrene in the range of 0~0.16 mole. Isoelectric point of $TiO_{2}$ in the acrylic resin placed in the neutral region whereas that of $TiO_{2}$ in the water placed in the acidic region, indicating that zeta potential and agglomeration of $TiO_{2}$ powder is strongly dependent on the pH and the type of solvent. To prepare an adhesion, an acrylic resin containing fluorostyrene was synthesized by a radical polymerization. The adhesion of coating layer was increased with increasing fluorostyrene's contents without changing the dispersion stabilities and degrading photocatalytic properties.

• 지질공학
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• 제20권3호
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• pp.271-279
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• 2010

광물의 용해현상과 밀접하게 관련된 암석의 시간의존성 변형과 파괴현상은 실내시험에서 비교적 용이하게 관찰된다. 본 연구에서는 고준위 방사성폐기물의 지하 처분장 건설시 완충제로 사용되어지는 벤토나이트에 많이 포함된 석영의 고 알칼리 환경 하에서의 용해 현상을 정량적으로 관찰하기 위해서 수산화 이온의 확산과 석영의 용해 문제를 균질화 해석법을 이용하여 평가하였다. 해석결과에 의하면 석영의 용해량은 주변 환경의 온도 및 층간수의 두께와 비례한다. 특히 고알칼리 환경 하에서는 층간수의 두께가 작아지면서 반응표면적이 커지게 되고 그 결과 용해 속도는 층간수의 두께가 작아질수록 커지는 결과를 나타내고 있다.

• 한국수산과학회지
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• 제45권5호
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• pp.430-437
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• 2012

The effects of low temperature and starvation on the physiochemical characteristics of the muscle of the olive flounder Paralichthys olivaceus, were examined. Fish were deprived of feed for 28 days at 2, 4, 6, 8, 10, 12, and $20^{\circ}C$ in order to establish suitable conditions for live fish transportation. Throughout most of the 4 weeks of feed restriction, the physiochemical characteristics of the muscle of olive flounder were found to be dependent on the acclimation temperature. The breaking strength of muscle did not show a significant reduction during feed restriction at 2 and $4^{\circ}C$. With increasing temperatures, however, the breaking strength of muscle differed significantly according to the individual and feed restriction period (P<0.05). The moisture content in muscle acclimated at 10, 12, and $20^{\circ}C$ increased steadily over the feed-restriction period, while the crude lipid content decreased during the same period (P<0.05). At water temperatures above $2-8^{\circ}C$, no significant differences were shown during the same period. After it reached 6, 8, 10, 12, and $20^{\circ}C$, the muscle had an accumulation of lactate, and a loss of ATP. There was no change in the lactate or ATP content during the feed restriction period at 2 and $4^{\circ}C$, although there were differences among the water temperature groups. These results clearly show that temperature can have an important influence on the of muscle of physiochemical characteristics of muscle during live fish transportation.

• Fisheries and Aquatic Sciences
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• 제25권3호
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• pp.175-186
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• 2022

Sea mustard (Undaria pinnatifida), an important edible seaweed belonging to the brown algal family of Alariaceae, contains copious physiologically active substances. It has long been popular in Korea as a food and is frequently consumed in the form of soup. It is also commercially available as a home meal replacement. In this study, we developed a seasoning key base with a high degree of sensory preference from sea mustard using the extrusion cooking process. Extrusion cooking conditions were optimized through response surface methodology. Barrel temperature (X₁, 140℃-160℃) and screw speed (X₂, 158-315 rpm) were set as independent variables, and overall preference was determined as the dependent variable (Y, points). An optimal condition was obtained at X₁ = 148.5℃ and X₂ = 315 rpm, and the dependent variable (Y, overall acceptance) was 7.95 points, similar to the experimental value of 7.81. Umami taste had a relationship with the overall acceptance of sea mustard seasoning. In the electronic nose and tongue, increased sourness and umami intensities were associated with the highest sensory score. The samples were separated well by each characteristic via principal component analysis. Collectively, our study provides imperative preliminary data for the development of various seasonings using sea mustard.

• 한국농공학회지
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• 제32권E호
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• pp.80-87
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• 1990

Energy balance equations Were developed to describe the heat transfer mechanisms in a double layer plastic greenhouse with a water curtain system. Heat transfer variables were determined by using various temperature data measured in a conventional prototype semicircular cross-section greenhouse over a range of water temperatures and water flow rates. The heat transfer coefficient between flowing water and greenhouse air was independent of water flow rates. But the heat transfer coefficient between water surface and the stagnant air space within the double plastic layer was dependent on water flow rates. Substituting the heat transfer coefficients, determined from the energy balance equations in the heat transfer equations, demonstrated various relationships among ambient air temperature, greenhouse air temperature, water temperature, and water flow rates. The heating benefits were linearly related to not only the inside and outside air temperatures but also to the water temperature. The energy conservation effects of the water curtain system were found even initial water temperatures were considerably lower than the greenhouse setting temperatures. Sensitivity analysis for heat transfer coefficients demonstrated that the heat transfer coefficient between greenhouse air and the stagnant air within the plastic layers was the most significant coefficient in the estimation of heating effects.

• Journal of Photoscience
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• 제5권2호
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• pp.53-61
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• 1998

Using a squash plant, a chilling-sensitive species, and a spinach plant, a chilling-resistant one, effects of chilling temperature on the photosynthetic machinery were studied in terms of chlorophyll fluorescence. When thylakoid membranes were isolated and subjected to incubation at different temperatures, spinach showed stable photosystem II activity at the low temperature side, in contrast to squash which showed quite severe inactivation at low temperature. When parameters of chlorophyll fluorescence were examined, chilling in darkness did not affect either Fv/Fm or photochemical and non-photochemical quenching, in both types of plants. However, chilling of squash plants under irradiance of medium intensity caused a specific decrease in Fv/Fm accompanied by a decline in energy-dependent quenching. Contrastingly, photosystem li of spinach plants were not much affected by light-chilling. When the pool size of zeaxanthin was examined after exposure to high light at different temperatures, squash plants was shown to have a much lower content of antheraxanthin + zeaxanthin, as compared to spinach plants, during low-temperature photoinhibition. These results suggest that chilling-sensitive plants have low capacity to dissipate excitation energy nonradiatively, when they are exposed to low-temperature photoinhibition, and, as a consequence, more vulnerable to photoinhibitory, damage to the photosynthetic apparatus.