• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.160-165
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• 1998

The Joint curing barns for flue-cured tobacco is a favorite with the tobacco farmers in Korea. However, most of farmer utilizing the joint curing barns indicated many problems such as high temperature and noise in the working room and a dry of cured leaves in the storage room. A structure of Joint curing barns has been modified to meet the needs of tobacco farmers. Compared with the unimproved joint curing barns, the improved one showed that the noise of workshop decreased about 7.7～10.8db, the amount of $CO_2$ decreased 40～50ppm in a working room and 80～100ppm in a machine room. Ammonia gas decreased 0.29mg/㎥ and the temperature of a working room dropped about 2.1～3.5$^{\circ}C$. The amount of air flow in a working room increased 23.2% at a site being 2m away from the entrance and 30.8% at a center. The inner temperature of the improved storage room showed that maximum temperature dropped about 3$^{\circ}C$, minimum temperature was high about 2$^{\circ}C$. The highest relative humidity was low 6%, the lowest one increased high about 10% when compared with the unimproved joint curing barns.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.143-144
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• 2019

This study introduces the production and construction of building interior and exterior materials using UHPC for premix type room temperature curing developed through advance research and development.

• Journal of Technologic Dentistry
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• v.12 no.1
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• pp.103-106
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• 1990

The purpose of this study was to determine if homogeneity of the resin associated with benchcuring could be obtained in the curing unit as the water increased from room temperature to curing temperature. The results of the experiment were as follows : 1. Long periods of bench-curing are not necessary. 2. Bench-curing can take place in the water bath of the curing unit. When this procedure is used, the water should be far enough below the temerature at which active polymerization of the resin proceeds to allow the bench-curing to occur.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.4
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• pp.404-409
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• 1983

The warping of unsymmetric laminated composites is induced by residual curing stress at the room temperature. Classical lamination theory (C.L.T.) predicts the room temperature shapes of all unsymmetric laminates to be a saddle. Experimental observations, however, indicate some unsymmetric laminated composites have cylindrical room temperature shapes. This anomalous behavior is explained by the extention of C.L.T. which involves Von Karman's large deflection theory. It is shown that, depending on the thickness, width, length, curing temperature and room temperature of the laminate, critical boundaries of the shape change are determined. Theoretical predictions are compared with experimental results of Toray Graphite/Epoxy {O$_{n}$/90$_{n}$}$_{T}$./....

• The Journal of the Korean dental association
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• v.11 no.1
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• pp.37-40
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• 1973

The auther measured exothermic tempreature of the 5 kinds of direct resins during polymerization. Direct resins were mixed into the rubber cup(550-600㎣ in volume) with grass rod at room temperature (23.6℃) for 30 seconds and thermometer was placed approximately at the geometric center of the resin mass in the rubber cup. Polymer-monomer ratio was determined by instruction of the packages. The results were as follows. 1) The heat generated during polymerization was under 47.3℃. 2) The time at which the highest temperature is reached during polymerization was within 20.5 minutes. 3) Slow curing resins produced lower heat than quick curing resins and quick curing resins presented higher temperature than slow curing resins. 4) The highest temperature was sustained momentarily.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.7
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• pp.602-609
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• 2008

This paper presents experimental optimization of process parameters for a newly developed SFF(Solid Freeform Fabrication) system. Two critical process parameters, layering thickness and curing period, which have a large effect on the quality of the product, are optimized through experiments. Specimens are produced using layering thicknesses of 60, 80, 100, 120, 140, and $160\;{\mu}m$ and curing periods of 0, 10, 20, and 30 minutes under the same processing conditions, i.e., build-room temperature, feed-room temperature, roller speed, laser power, scan speed, and scan spacing. The specimens are tested to compare and analyze performance indices such as thickness accuracy, flatness, stress-strain characteristics, and porosity. The experimental result indicates that layering thickness of $80{\sim}100\;{\mu}m$ and curing period of $20{\sim}30$ minutes are recommended for the developed industrial SFF system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.3
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• pp.203-209
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• 2012

In this paper, cross-sectional stiffnesses, static stresses, and dynamic natural frequencies are analyzed to examine the structural performance of wind turbine composite blades. The material properties of composite materials are based on room-temperature and radiation curing processes. The cross-sectional stiffnesses of composite blades are calculated by applying a beam theory with solid-profile cross sections. The wind turbine blades are modeled with a finite element program, and static analyses are carried out to check the maximum displacement and stress of the blades. In addition, dynamic analyses are performed to predict the rotating natural frequencies of the composite blades including the effects of centrifugal force. By comparing these analysis results, mainly owing to the material properties of composite materials, an improvement in the structural performance of the blades according to the curing process is investigated.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.293-295
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• 1987

This paper deals with the dielectric properties dielectric breakdown strength and mechanical tensile properties according to heat - treatment condition of polyurethane resin. This resin is heat - treated over a range of temperature from $50^{\circ}C$ to $150^{\circ}C$. It is shown that the dielectric dissipation factor decreases with increase of heat - treatment temperature of the sample exept for the sample heat - treated at $150^{\circ}C$. The maximum dielectric breakdown strength is appeared for the sample heat - treated for 10 hours at $100^{\circ}C$, after curing for 24 hours at room temperature. The optimal heat - treatment condition in the view point of the electrical and mechanical properties is appeared for the sample heat - treated for 10 hours at $100^{\circ}C$, after curing for 24 hours at room temperature.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.7
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• pp.511-523
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• 1989

This paper investigates physical properties, the electrical and mechanical characteristics of the epoxy resin with different curing methods and postcuring conditions at room temperature or cryogenic temperature (LN2). According to the results in this paper, first, it is found that the physical properties, electrical and mechanical characteristics of the epoxy resin are largely affected by the interior reaction temperature on the curing. Thus, in the fabrication of the sample, several excellent characteristics of the sample are obtained by controlling the interior reaction temperature of the epoxy resin. Second, the sample having optimal electrical and mechanical characteristics is obtained for the repetitive post-curing method at 100c in view point of the post-curing conditions of the epoxy resin. Third, it appears that tan and characteristics at LN2 temperature are about half of those at room temperature. Fourth, it appears that the dielectric strength of the epoxy resin at LN2 temperature is higher by about 0.6-1.0 MV/cm than that at room temperature. The heat-aging of the epoxy resin due to the micro-defect and excess fever-movement have been noticed to affect dielectric strength at LN2 temperature more significantly than at room temperature.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.6
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• pp.295-302
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• 2017

In this study, the effect of pre-curing process on the enhancement of mechanical properties of IGCC-slag-based-geopolymer was studied. Pre-curing is a process in which the green geopolymer is left at room temperature for a certain period of time prior to the high-temperature curing, and it is known as increasing the strength of a specimen. Therefore, in this experiment, the compressive strength of the geopolymers was measured according to various pre-curing conditions, and microstructure and crystal phase changes were observed by SEM and XRD, respectively. The W/S ratio was determined to be 0.26, which can offer the maximum geopolymer strength with easy molding ability, and the concentration of the alkali solution was 15 M. Pre-curing was performed at room temperature for 0 to 27 days. Compressive strength of the geopolymer made with pre-curing process increased by 36~87 % compared with the specimens made with no pre-curing process. Those improved compressive strength for the pre-cured geopolymer was confirmed owing to promotion effect of pre-curing process on generation of C-S-H gel and zeolite phases, which were analyzed using by XRD and SEM measurement.