• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.393-398
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• 2001

Polymerization of light-activated restorations results in temperature increase caused by both the exothermic reaction process and the energy absorbed during irradiation. Within composite resin, temperature increases up to 2$0^{\circ}C$ or more during polymerization. But, insulation of hard tissue of tooth lowers this temperature increase in pulp. However, many clinicians are concerned about intrapulpal temperature injury. The purpose of this study was to evaluate temperature changes in the pulp according to various restorative materials and bases during curing procedure. Caries and restoration-free mandibular molars extracted within three months were prepared Class I cavity of 3$\times$6mm with high speed handpiece fissure bur. 1mm depth of dentin was evaluated with micrometer in mesial and distal pulp horns. Pulp chambers were filled with 37.0$\pm$0.1$^{\circ}C$ water to CEJ. Chromium-alumina thermocouple was placed in pulp horn below restorative materials for evaluating of temperature changes. This thermocouple was connected to temperature-recording device(Multiplication analyzer MX, 6.000, JAPAN). Temperature changes was evaluated from initial 37.$0^{\circ}C$ after temperature changes to 37.$0^{\circ}C$. Tip of curing unit was placed in the center of prepared cavity separated 1mm from restorative materials. Curing time was 40s. The restorative materials were used with Z 100, Fuji II LC, Compoglass flow and bases were used with Vitrebond, Dycal. Resrorative materials were placed in 2mm. The depth of bases were formed in 1mm and in this upper portion, resin of 2mm depth was placed. This procedure was performed 10 times. The results were as follows. 1. All the groups showed that the temperature in pulp increased as curing time increased 2. The temperature increase of glass ionomer was significantly higher than that of Resin and Compomer during curing procedure (P<0.05). 3. The temperature increase in glass ionomer base was significantly higher than that of Calcium hydroxide base during Resin curing procedure (P<0.05).

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.200-204
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• 2008

The curing kinetics of diglycidyl ether of bisphenol F (DGEBF) with an asymmetric cycloaliphatic amine curing agent were examined by thermal analysis in both isothermal and dynamic curing conditions. From the residual curing of the samples partially cured in isothermal condition and from the dynamic curing with various heating rates, it was found that there exist two kinds of reactions such as at low temperature and at high temperature regions. It was thus also found that the cure parameters obtained from the isothermal curing kinetic model hardly estimate experimental results for a degree of cure larger than 0.6. The activation energies and frequency factors of these two kinds of reactions were obtained from the dynamic curing experiments with various heating rates. From the curing analysis, it was verified that the total cure kinetics for low degrees of cure is dominated by the cure reaction in the low temperature region.

• Computers and Concrete
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• v.24 no.3
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• pp.249-258
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• 2019

In order to investigate the strength recovery of fire-damaged concrete after post-fire curing, concrete specimens were heating at $2^{\circ}C/min$ or $5^{\circ}C/min$ to 400, 600 and $800^{\circ}C$, and these exposed specimens were soaked in the water for 24 hours and following by 29-day post-fire curing. The compressive strength and split tensile strength of the high-temperature-exposed specimens before and after post-fire curing were tested. The proportion of split aggregate in the split surfaces was analyzed to evaluate the mortar-aggregate interfacial strength. After the post-fire curing process, the split tensile strength of specimens exposed to all temperatures was recovered significantly, while the recovery of compressive strength was only obvious within the specimens exposed to $600^{\circ}C$. The tensile strength is more sensitive to the mortar-aggregate interfacial cracks, which caused that the split tensile strength decreased more after high-temperature exposure and recovery more after post-fire curing than the compressive strength. The mortar-aggregate interfacial strength also showed remarkable recovery after post-fire curing, and it contributed to the recovery of split tensile strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.141-142
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• 2019

In this study, we conducted a comparative analysis of the effects of retention time and resuscitation method on the degree of resuscitation after reapplying mortar with much FA replacement. Results After applying NaOH to the top surface of 60 % FA-substituted mortar, the degree of resuscitation at $40^{\circ}C$ was high enough to increase the overall curing time, but there was no significant difference. However, with regard to the curing method, middle curing showed the greatest manifestation, followed by wrapping and underwater curing, but there was no significant difference. The resuscitation level on the 28th of the lumber was found to be revived to about 70~80 % at around 30 % without resuscitation.

• Elastomers and Composites
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• v.52 no.4
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• pp.266-271
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• 2017

This study describes the influence of the amount of curing agent and curing temperature on the kinetics of polyurethane elastomers. The urethane prepolymer series was prepared by reacting toluene diisocyanate with polytetramethylene ether glycol at $80^{\circ}C$ for 1 h, and 4,4'-methylene bis(2-chloroaniline) was used as the curing agent. The ratio of the amine group of the curing agent to the isocyanate group of the urethane prepolymer was controlled from 0.85 to 1.05 at curing temperatures ranging from 80 to $120^{\circ}C$. The curing rate of the urethane prepolymer was monitored by observing the change in heat flow during the curing process using differential scanning calorimetry (DSC). As either the content of curing agent or the curing temperature was higher, the conversion rate to the polyurethane elastomer was high. The DSC results were compared with those obtained from using real-time FT-IR.

• Journal of Korean Society for Quality Management
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• v.16 no.1
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• pp.43-48
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• 1988

Most of silicone used for water repellent finish is MHP (methyl hydrodiene polysiloxane), which is formed by hydrolysis and condensation polymerization of MHD (methyl hydrodiene dichlorosilane: Me H Si $Cl_2$). The cross-linking theory explains the water repellent mechanism of MHP. The silicone finish on fiber could improve in handle, softness, abrasion resistance, soil repellency, tear strength and crease resistance, as well as water repellency. According to using method silicone-water repellent finishing agents, could be devided into air dry type and curing type. MHP is the typical curing type of water repellent finishing agent, and this type requires the curing temperature above $150^{\circ}C$ at least. High curing temperature is the very drawback of this curing type. For this reason, there has been global interest in the lowering of its temperature. The objective of this study is to investigate merits of alkali treatment for silicone finishing by ANOVA and LSD (least significant difference).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.53-54
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• 2023

In recent decades, climate change has become an issue of global importance. The calcium sulfoaluminate (CSA) cement emits lower CO₂ than the Portland cements while manufacturing. However, ettringite, which is a main hydration product of CSA cement, starts dehydrating at a temperature above 100℃, hence it may limit the CSA cement for high temperature application. Recently, an early carbonation curing of cement-based material has been extensively studied in terms of carbon neutralization. The carbonation curing of CSA cement has a potential to transform the AFt and AFm phases into calcium carbonate, and the transformation of unstable hydrates to stable hydrates can increase the resistance to elevated temperature. This review study summarizes and discusses the carbonation curing effect of CSA cement and the thermal stability of CSA cement exposed to elevated temperatures.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.8
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• pp.653-658
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• 2014

Roll-to-Roll printing process has become a great issue as a breakthrough for low cost and mass production of electronic devices such as organic thin film transistor, and etc. To print the electronic devices, multi-layer printing is essential, and high precision register control is required for this process. Unlike stop-and-repeat printing process, it is impossible to control the register in a static state since the roll-to-roll process is a continuous system. Therefore, the behavior of web such as polyethylene terephthalate (PET) and polyimide (PI) by the tensile and thermal stress generated in the roll-to-roll process as well as motor control of driven rolls has to be considered for a high precision register control. In this study, the correlation between curing temperature and thermal deformation of PET web is analyzed. Finally, it is verified experimentally that the temperature disturbance generates the more serious register error under the higher curing temperature.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.351-354
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• 2005

Quality of concrete required to achieve the desired levels of strength and durability depend on the effectiveness of the curing method. During cold weather, the concrete at the time of placement should be taken to prevent damage to concrete due to freezing. Since the cement-water reaction is exothermic by nature, the temperature within mass concrete can be quite high. The temperature control for massive sections should be taken more careful than for shallow sections. However, in the constructing hydraulic structures, the curing temperature control for concrete had been very difficult to be taken in a proper way because the conditions constructing them are poor and contractors are small enterprises. For several. reasons including above, Rural Research Institute has developed a device and program for recording curing temperature history in cold weather concrete and mass. As there are two major advantages of the device, namely cheapness and availability, this program and device has been recommended to the use of curing temperature control in cold weather concrete and mass.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.66-73
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• 2007

This study was carried out to investigate the changes of curing condition on microclimate of temperature, relative humidity during curing process of burley tobacco leaves. The developed facility, ridge opening type was designed to open the central top roof. The air-cured variety, (N. tabacum cv KB111) was normally grown at the Eumseong tobacco experimental station in 2007. Mean daily temperature of $3^{\circ}C$ in ridge opening type curing facility was lower than that of conventional, whereas mean daily relative humidity of 12.6 % RH was lower in conventional curing facility for the entire stage of curing. The frequency distribution of optimal air temperature at daytime was higher 37.5 % in ridge opening type curing facility than that of conventional, while that of optimal relative humidity was lower 8.2 %. In the ridge opening type curing facility, the excessive drying leaves were low, however the price per kilogram was high. These results suggest that the new developed curing facility may be applied to improved microclimate inside the curing facility for curing burley.