• The Journal of Korean Academy of Prosthodontics
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• v.40 no.3
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• pp.236-245
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• 2002

The acrylic resin was first introduced as denture base materials in 1937 and it is commonly used for denture base fabrication nowadays. Three different curing cycles (Conventional curing cycle, short curing cycle and long curing cycle) and three commercially available heat-activated acrylic resins (Vertex RS, Lucitone 199 and ProBase Hot) were investigated to find the curing cycle and material that showed the minimum shrinkage of the resin during polymerization process. A brass master mold was fabricated and duplicated by additional silicone impression material. Stone molds were made by pouring of type III dental stone (SILKY-ROCK YELLOW, Whip-Mix, Louisville, Kentucky). It was embedded in the flask. Strain gauge and thermocouple were embedded in the specimen. Strain gauge and thermocouple were connected to signal conditioning amplifier and data was recorded by pre-programmed software. The parameters ESmax (Maximum expansion strain), Sb (Strain measured just before deflasking procedure), Sa (Strain measured just after deflasking procedure) and Sf (Strain measured at the end of the experiment) were measured. ${\Delta}$S was calculated from Sb and Sa (${\Delta}$S=Sb-Sa). In the experiment concerned about materials, the parameters 90-ESmax (Maximum expansion strain measured during early 90 minutes of curing procedure), 180-ESmax (Maximum expansion strain measured from 90 minutes to 180 minutes), Sb, Sa, ${\Delta}$S and Sf were measured and the following conclusions were made. 1. The ESmax value of conventional curing cycle showed the largest value and the 180-ESmax value of Lucitone 199 showed the smallest value. 90-ESmax values showed no significant difference (p<0.05). 2. ${\Delta}$S values of conventional curing cycle showed the positive values. ${\Delta}$S values of short curing cycle and long curing cycle showed the negative values. All three materials cured by conventional curing cycle showed the positive values. 3. The Sf values of long curing cycle and ProBase Hot (cured by conventional curing cycle) showed the smallest values.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.63-71
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• 2010

This paper is about a research of steam curing which is one of the curing methods for accelerating the early-age strength of pre-cast concrete. With cylinder mold and mock-up specimen, the research was executed to study the best cycle of steam curing temperature through quantifying cycle of steam curing and maximum temperature, while the required strength is developed under the early-age. Moreover, causes and measurements for the high temperature of concrete, which is due to the steam curing, and the crack, which occurs when removing steel form, are stated. Ultimately, the economical method of producing, which satisfies early-age strength development and quality assurance while manufacturing PC structure, is stated.

• Journal of the Korean Applied Science and Technology
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• v.25 no.1
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• pp.41-47
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• 2008

This study was conducted to made a grid alloy (Pb-Ca-Sn-Al) which has a temporary composition ratio in order to improve the efficiency of lead acid batteries. The positive activity material made a 3BS(tri-basic lead sulfate; $3PbO{\cdot}PbSO_4{\cdot}H_2O$) by a low temperature curing and it evaluates the plate efficiency through the life cycle testing. The initial current capacity of low temperature curing plate was excellent but the life cycle was not good (S1). As for the S2 plate, however, the initial current capacity and the life cycle were superior.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.197-202
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• 2014

Positive plate was composed of lead hydroxide via reaction between lead oxide and $H_2O$ and lead sulfate was formed of the reaction of lead hydroxide with sulfuric acid. And its density is $3.8g/cm^3$, $4.0g/cm^3$, $4.2g/cm^3$ and $4.4g/cm^3$ by controlling volume of refined water. Curing of positive plate is done for low ($45^{\circ}C$, 40hr, over 95% of relative humidity) & high ($80^{\circ}C$, 40hr, over 95% of relative humidity) temperature, which created 3BS & 4BS active materials. Experimental result of DOD with 100% life cycle test shows that it was not related to the density of active materials but to the low & high temperature aging of active materials. The test makes us to understand that the crystallization which is made by curing of active materials is a more of a main factor than density of active materials under the deep cycle using circumstances. The active materials which were from the high temperature curing are better for deep cycle performance.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.83-87
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• 2004

In this work, the cure cycle of co-cured metal/composite structure was investigated to decrease fabricating thermal residual stresses between the metal and the composite material. DSC (Differential scanning calorimetry) experiment and static lap shear test of co-cured aluminum/composite double lap joint as well as the curvature experiment of co-cured steel/composite strip were performed to investigate the effect of curing cycle on the thermal residual stress of co-cured hybrid structures. From the experiments, it was found that post curing method after abrupt cooling of co-cured aluminum/composite hybrid structure at certain point of degree of cure during curing process could eliminate fabricating the thermal residual stresses.

• Journal of the Korean Applied Science and Technology
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• v.26 no.3
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• pp.335-340
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• 2009

This study investigates the paste mixing of positive active materials which, affect the life cycle of batteries in Pb-Ca-Sn grids, and generation of 4BS in a curing process and considers the effects of these things on the initial charge characteristics and life cycle. In the results of the experiments applied in this study, it was possible to reduce the curing time in which the fine 4BS was formed by the mixing of the positive active materials of lead acid battery applied at high temperature compared to that of the existing coarse 4BS and that represented some improvements in the life cycle performance.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.3
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• pp.60-74
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• 1980

Soil-cement mixtures involve problems in it's durability in grain size distribution and mineral composition of the used soils as well as in cement content, compaction energy, molding water content, and curing. As an attempt to solve the problems associated with durability of weathered granite soil with cement treated was investigated by conducting tests such as unconfined compression test, it's moisture, immers, wet-dry and freeze-thaw curing, mesurement of loss of weight with wet-dry and freeze-thaw by KS F criteria and CBR test with moisture curing on the five soil samples different in weathering and mineral composition. The experimental results are summarized as follows; The unconfined compressive strength was higher in moisture curing rather than in the immers and wet-dry, while it was lowest in freeze-thaw. Decreasing ratio of unconfined compressive strength in soil-cement mixtures were lowest in optimum moisture content or in the dry side rather than optimum moisture content with freeze-thaw. The highly significant ceofficient was obtained between the cement content and loss of weight with freeze-thaw and wet-dry. It was possible to obtain the durability of soil-cement mixtures, as the materials of base for roads, containing above 4 % of cement content, above 3Okg/cm$_2$ of unconfined compressive trength with seven days moisture curing or 12 cycle of freeze-thaw after it, above 100% of relative unconfined compressive strength, 80% of index of resistance, below 14% of loss of weight with 12 cycle of wet-dry and above 1. 80g/cm$_2$ of dry density.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.347-350
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• 2005

The strength level for removal of lining concrete in tunnel is increased from 2.94MPa to 4.9MPa in 2004. This result in the increase of concrete curing time, and construction time would be delayed. In this study, in order to improve the efficiency of construction cycle and satisfy the strength criterion, a curing method is adopted, which is considering the hydration heat in the lining concrete member. As a result, it is shown that the concrete curing time for form removal is about 20hrs without the adjustment of concrete mix design. And construction cycle time is not changed compared to that before the change of strength criterion.

• Journal of the Korean Applied Science and Technology
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• v.27 no.2
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• pp.196-201
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• 2010

The influence of red lead($Pb_3O_4$) to curing and formation reaction properties when it was added in positive material of lead acid battery for vehicle use has been investigated. At the results, it was confirmed that the addition of red lead led 4BS crystal size to be smaller and increased the rates of 4BS formation and Pb consumption. Consequently the curing time was shortened to half compared with that of red lead-free one. In addition to this, the lead acid battery prepared by adding red lead showed 14% higher efficiency at the life cycle test than that without red lead.

• Journal of the Korea Institute of Building Construction
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• v.8 no.4
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• pp.115-121
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• 2008

The present study performed low-pressure steam curing with mortar specimens in order to examine the temperature profile and strength development of steam curing in high-strength specimens of 100MPa. In addition, as a basic research to utilize PC products, we examined the effects of curing temperature and time in steam curing cycle on strength development resulting from the hydration of cement within the range of high strength by changing four factors affecting the quality of PC displacement time, peak curing temperature, peak temperature duration, and ascending and descending gradient of temperature - in various patterns, and analyzed the optimal strength development characteristic based on the relation between temperature profile and strength development. With regard to the high-temperature curing characteristic of PC, we performed an experiment on the strength characteristic according to the temperature profile of high-strength mortar, and from the results of the experiment according to curing characteristic, displacement time, peak curing temperature, peak temperature duration, and ascending and descending gradient of temperature, we drew conclusions as follows.