• Journal of Nutrition and Health
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• v.47 no.6
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• pp.484-488
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• 2014

Purpose: This study investigated the question of whether the addition of natural ingredients (pear fermented solution, celery powder, vitamin C) in curing agents may influence antioxidant activities and nutritional characteristics of smoked duck. Methods: Smoked duck samples with general or natural curing agent containing three additive ingredients were examined to determine total polyphenol contents, antioxidant activities, pH, TBARS, and food additives residue (nitrite ion, antioxidant, sodium glutamate). Results: Smoked duck with natural curing agent showed a higher level of total polyphenol content and antioxidant activities than smoked duck using general curing agent (p < 0.05). The pH and TBARS of smoked duck were significantly decreased by the addition of natural curing ingredients compared to those of smoked duck using general curing agent (p < 0.05). The residues of food additives were not detected in smoked duck using natural curing agent. Conclusion: Findings suggest that the addition of pear fermented solution, celery powder, and vitamin C in natural duck curing agent may improve the antioxidant activities and nutritional characteristics of smoked duck and provides health benefits.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.967-972
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• 2001

In this study, the characteristics of freezing and thawing resistance, the compressive strength, and the change in height of cement mortar according to steam curing methods has been studied. To this end, the major test variables include the period of the early curing, curing temperature and the later curing. The strength test as well as volume variousness have been conducted to explore the characteristics of thawing and thawing resistance on the curing methods. The experimental results in the present study can be efficiently used to improve the characteristics of freezing and thawing resistance for concrete products carrying steam curing.

• Journal of the Semiconductor & Display Technology
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• v.21 no.2
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• pp.57-67
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• 2022

The curing characteristics of naphthalene type epoxy resin systems according to the change of curing agent were investigated to develop a new next-generation EMC(Epoxy Molding Compound) with excellent warpage characteristics, low thermal expansion, and excellent fluidity for WLP(Wafer Level Package). As epoxy resins, DGEBA, which are representative bisphenol type epoxy resins, NE-16, which are the base resins of naphthalene type epoxy resins, and NET-OH, NET-MA, and NET-Epoxy resins newly synthesized based on NE-16 were used. As a curing agent, DDM (Diamino Diphenyl Methane) and CBN resin with naphthalene moiety were used. The curing reaction characteristics of these epoxy resin systems with curing agents were analyzed through thermal analysis experiments. In terms of curing reaction mechanism, DGEBA and NET-OH resin systems follow the nth curing reaction mechanism, and NE-16, NET-MA and NET-Epoxy resin systems follow the autocatalytic curing reaction mechanism in the case of epoxy resin systems using DDM as curing agent. On the other hand, it was found that all of them showed the nth curing reaction mechanism in the case of epoxy resin systems using CBN as the curing agent. Comparing the curing reaction rate, the epoxy resin systems using CBN as the curing agent showed a faster curing reaction rate than them with DDM as a hardener in the case of DGEBA and NET-OH epoxy resin systems following the same nth curing reaction mechanism, and the epoxy resin systems with a different curing mechanism using CBN as a curing agent showed a faster curing reaction rate than DDM hardener systems except for the NE-16 epoxy resin system. These reasons were comparatively explained using the reaction rate parameters obtained through thermal analysis experiments. Based on these results, low thermal expansion, warpage reduction, and curing reaction rate in the epoxy resin systems can be improved by using CBN curing agent with a naphthalene moiety.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.185-188
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• 2001

In this study, the characteristics of freezing and thawing resistance, the compressive strength, and the change in height of cement mortar according to a steam and taler curing conditions has been studied. To this end, the major test variables include the period of the early curing, curing temperature and the later curing. The strength test as well as volume variousness have been conducted to explore the characteristics of freezing and thawing resistance on the curing conditions. The experimental results can be efficiently used to improve the characteristics of freezing and thawing resistance for concrete products carrying steam curing.

• Journal of Adhesion and Interface
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• v.7 no.4
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• pp.45-52
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• 2006

Five low molar ratio urea-formaldehyde (LUF) resins were synthesized in this study. The effects of molar ratio, free formaldehyde content, and catalysts on the curing characteristics of LUF resins were studied by measuring its free formaldehyde content, pH value change after catalysts added, curing rate, and pot life, observing its cured appearance, and analyzing its thermal behavior. The results indicate that: 1) The LUF resin with lower molar ratio than 1.0 can still cure; 2) Free formaldehyde content is not the main factor in affecting curing rate of LUF resin; 3) Compared with ammonium chloride as a traditional catalyst, persulfate salts markedly accelerate the curing rate of LUF resin, and result in the different appearance; 4) the addition of sodium chloride to catalysts can accelerate the curing rate of LUF resin, but the effect is moderate.

• Journal of the Korea Institute of Building Construction
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• v.2 no.4
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• pp.163-168
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• 2002

The object of this study is to define the characteristics of high performance concrete with varing compressive strength of concrete and curing temperature. The major test variables are 1) high strength concrete(500kg/$cm^2$) and ordinary strength concrete(240kg/$cm^2$) compressive strength, 2) curing temperature and condition, 3) concrete curing age, 4) three types of cement. From the test results were shown that curing temperature and curing conditions were also very effective for high strength concrete and ordinary strength concrete, and concrete were largely effected by cement type and temperature during the hydration reaction process. This paper describes the effect of curing temperature for strength and characteristics of high performance concrete.

• Journal of Urban Science
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• v.12 no.1
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• pp.1-10
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• 2023

The cement industry is a major source of carbon dioxide emissions. Reduction in emissions in this sector is an important issue. Calcium silicate cement is a type of alternative to ordinary Portland cements which contributes to the reduction in carbon dioxide emissions. However, because the type of cement is a non-hydraulic material, there are limitations to its application in the field. The effects of pre-curing periods on the physical characteristics of ordinary Portland cement pastes with calcium silicate cement in the present study were investigated. The Independent variable is the pre-curing period. The pre-curing period varied from 0 to 5 hrs, considering the hydration characteristics of ordinary Portland cement. The carbonation curing of the ordinary Portland cement pastes with the calcium silicate cement after pre-curing was conducted. The concentration of gaseous CO₂ was fixed at 20 %. The test results showed that the pre-curing period led to the pore structural change of the pastes, which in turn could affect the further reaction under the long-term curing condition.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.695-702
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• 1998

The purpose of this study is to investigate the mechanical properties of precast concrete cured by accelerated curing methods such as, steam curing method and warm water curing method varing maximum temperature of curing along to the period of curing. Some specimens are cured by accelerated curing method(warm water curing method) and then deposited in the storehouse. The others are deposited in the storehouse directly. All of these are cured until being tested to compare these two group's mechanical characteristics for each period 3days, 7days, 28days. The goal of this comparison is to estimate the efficiency of accelerated curing method in the case of precast concrete stocked in the field or warehouse for a long term and to make guide line for factory manager to make a economical products of concrete of a good quality. We can conclude some guide lines 1) It is not efficient to cure concrete with accelerated method at higher than 80℃. 2) The continuing of curing period more than 36hr makes damage to concrete in using accelerated curing method. 3) The strength revelation of concrete cured by accelerated curing methods, added rice husk ash more delayed than OPC concrete done but the strength of maximum value is higher than OPC concrete. 4) It is not efficient to use accelerated curing method in the case of storing the products for more than 7days in the aspect of mechanical properties.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.397-402
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• 2001

Microstructural characteristics such as hydrates and porosity greatly influence the development of concrete strength. In this study, a strength estimation model for early-age concrete considerig, the microstructural characteristics was proposed, which considers the effects of both an increment of degree of hydration and capillary porosity on a strength increment. Hydration modeling and compressive strength test with curing temperature and curing ages were carried out. By comparing test results with estimated strength, it is found that the strength estimation model can estimate compressive strength of early-age concrete with curing ages and curing temperature within a margin of error.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.1
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• pp.12-18
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• 2001

This study was conducted to investigate the effect of tobacco curing on far infrared light on the quality of flue-cured tobacco leaves. Physicochemical characteristics such as alkaloid, total sugar, total nitrogen, starch, total phenolic compounds, browning degrees, and color differences, in cured tobacco leaves were compared between hot air and far infrared curing methods. There was no significant difference in sugar/nicotine ratio and nitrogen number between the curing methods, while the contents of ether extract and filling capacity were increase by far infrared curing. Therefore, it was expected that far infrared curing might be effective for high aroma and physical properties of the cured tobacco leaves.