• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.120-121
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• 2017

Generally, slump of plain concrete slab is about 120~150mm and slump loss is easy to occur. So, water is added to concrete because this method is convenient for Placing. In order to solve this problem, performance evaluation of concrete using improvement type PC admixture was carried out. Target slump is 210mm and compressive strength is 18MPa. As a result, slump reference value was satisfied 60 minutes after placing and 7-day compressive strength was 21~25MPa.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1300-1309
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• 2010

In the railway bridges, steel plate girder types are preferred due the high stability. Nevertheless, it has been pointed out that this type of bridge has problems such as, structural damages in the rail and girder seat, noise problem due to impact at the rail joint and excessive vibration. This vibration and/or deflection are mainly because insufficient stiffness of steel plate type of bridge. To resolve these problems, PC-Slab composite plate girder type which has simple process and economic cost, is proposed in this study. The static and dynamic experiment is performed by using the production of actual sized PC-Slab and abandoned steel plate girder. The object of this experiment is to verify the fact that girder stiffness increase and structural safety. The result of the experiment is used to analyze the effect of performance improvement of PC composite plate girder type. Using this method, economic rail maintainers, girder stiffness increase, and also speed/ride improvement even for existing rail could be expected by dynamic performance improvement. Additionally noise due to impact, deflection and vibration caused from long rails can be reduced.

• Journal of the Korea Institute of Building Construction
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• v.20 no.5
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• pp.449-457
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• 2020

Due to the improvement of living standards and avoidance of the 3D industry, it is difficult to find young and competent domestic workers at construction sites, and most foreign workers are contributing to the replacement, but the quality is still deteriorating due to lack of skilled workers and aging. Precast method is a method that make members in factory and assembles them on site, which can be expected to improve labor force and quality. This study is intended to provide basic data for the development of hang-type PC beams that can be applied to the determination of the field application of developed PC beams. The U-type connecting material is installed on both ends of the hang-up PC beam, and the role of the U-type connecting material is very important because it is a simple construction method through the U-type connecting material. In addition, the performance of the U-type connecting material will determine the performance of the hang-type PC beam as the final destruction occurs in the hang-type PC beam. The material properties of U-type connecting material were identified through structural experiments, and the end test corresponding to the partial experiment was conducted based on the material test results identified. Finally, the final design value of PC beams was proposed through structural experiments for application to the site.

• Geotechnical Engineering
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• v.13 no.6
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• pp.45-60
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• 1997

In this research the behavior of a new type of a single pile under lateral loading and against slope sliding is studied. Especially, the section of a new pile is determined throughout experiments, and the single pile behavior under lateral loading and the effect of improvement in slope stability by using new type of pile (gear-shaped) were studied. As a result, it is known that maximum deflection of gear-shaped pile is far smaller than that of traditional PC circular pile for the same lateral loading. And lateral load of gear-shaped pile at allowable deflection was bigger than that of PC circular pile. From the comparison between two hypes of piles, it can be seen that the degree of improvement of safety factor in slope was higher in gear-shaped pile than that of PC pile under the same condition, and it results in the reduction of the number of stabilizing piles in a slope.

• Journal of ILASS-Korea
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• v.7 no.2
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• pp.31-36
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• 2002

According to the improvement of PC performance, it is expected that calorific value, which causes PC to malfunction, is increased. Therefore, the development of new cooling system is recently required. As the method to solve this problem, we applied loop heat pipe to PC cooling system. The advantage of the loop heat pipe is that it has a small size, light weight, simple shape, long life and it has a good performance on heat transfer, no-noise, wide range of applicable temperature and no supply of power from the outside. It is confirmed that loop heat pipe reduces thermal resistance and has a good performance on PC cooling.

• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.654-659
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• 2010

We have investigated the effect of rubrene-doped CuPc hole transport layer on the performance of p-i-n type bulk hetero-junction photovoltaic device with a structure of ITO/PEDOT:PSS/CuPc: rubrene/CuPc:C60(blending ratio 1:1)/C60/BCP/Al and have evaluated the current density-voltage(J-V) characteristics, short-circuit current($J_{sc}$), open-circuit voltage($V_{oc}$), fill factor(FF), and energy conversion efficiency(${\eta}_e$) of the device. By rubrene doping into CuPc hole transport layer, absorption intensity in absorption spectra decreased. However, the performance of p-i-n organic type bulk hetero-junction photovoltaic device fabricated with crystalline rubrene-doped CuPc was improved since rubrene shows higher bandgap and hole mobility compared to CuPc. Increased injection currents have effected on the performance improvement of the present device with energy conversion efficiency(${\eta}_e$) of 1.41%, which is still lower value compared to silicone solar cell and many efforts should be made to improve organic photovoltaic devices.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.2
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• pp.27-34
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• 2008

Recently, owing to the development of industry and improvement of building techniques, concrete structures are becoming larger and higher. This study was performed to analyze hydration reation properties of concrete with binders and admixtures, such as OPC, low heat cement, belite rich cement, slag powder, lime powder and fly ash. To investigate effects of PC type superplasticizer on the hydration, experiments involving FT-IR, XRD, DSC, SEM were analyzed at the curing age 1day, 3days and 28days. The hydration reaction rate of OPC concrete slightly delayed at the curing age 1day, blast furnace slag powder and fly ash were more effective. BRC and LHC concretes can be used for concrete structures in winter season.

• Journal of the Korean Home Economics Association
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• v.29 no.3
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• pp.113-130
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• 1991

The objectives of study were 1) to investigate the motives for moving to the current residence, 2) to analyze residential satisfaction after moving in relation to household characteristics and the motives for moving, and 3) to test relationships among household characteristics, residential satisfaction before moving, motives for moving, and residential satisfaction after moving. Residential satisfaction was evaluated in relation to housing, neighborhood, and socio-psychological environments. Methdo-logy included literature and questionnaire survey. Questionnaires were administered to 269 homemakers living in an apartment complex in seoul. Data were analyzed with the use of SPSSS PC+ computer package. The motives for moving were classified in five types: tenureship improvement, improvement of the physical condition of housing, improvement of neighborhood environment, commuting improvement, and constraints. There were significant differences in the types of motives for moving by socio-economic status, types of houses lived in previously, change in type of tenures, and the duration of residence before moving. There were significant differences in residential satisfaction after moving among types of houses lived in previously, change in type of tenures, and the types of the motives for moving. There were significant relationships among residential satisfaction variables. They were the socio-economic status, change in type of tenures, residential satisfaction before moving.

• Fibers and Polymers
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• v.7 no.2
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• pp.89-94
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• 2006

Ionic conductivity and mechanical properties of a mixed polymer matrix consisting of poly(ethylene glycol) (PEG) and cyanoresin type M (CRM) with various lithium salts and plasticizer were examined. The CRM used was a copolymer of cyanoethyl pullulan and cyanoethyl poly(vinyl alcohol) with a molar ratio of 1:1, mixed plasticizer was ethylene carbonate (EC) and propylene carbonate (PC) at a volume ratio of 1:1. The conductive behavior of polymer electrolytes in the temperature range of $298{\sim}338\;K$ was investigated. The $PEG/LiClO_4$ complexes exhibited the highest ionic conductivity of ${\sim}10^{-5}S/cm$ at $25^{\circ}C$ with the salt concentration of 1.5 M. In addition, the plasticized $PEG/LiClO_4$ complexes exhibited improvement of ionic conductivity. However, their complexes showed decreased mechanical properties. The improvement of ionic conductivity and mechanical properties could be obtained from the polymer electrolytes by using CRM. The highest ionic conductivity of PEG/CRM/$LiClO_4$/(EC-PC) was $5.33{\time}10^{-4}S/cm$ at $25^{\circ}C$.

• Korean Journal of Adult Nursing
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• v.22 no.2
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• pp.130-142
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• 2010

Purpose: The purpose of this study was to analyze attitude toward dignified dying of Korean students majoring in human service area. Methods: The Q-methodology which provides a method of analyzing the subjectivity of each item was used. The 34 selected Q-statements from each of 38 subjects were classified into a shape of normal distribution using a 9 point scale. The collected data was analyzed using a QUANL PC program. Results: Four types of attitude toward dignified dying from the subjects were identified. Type I is an expression type for happy emotion, Type II is a dislike type for life prolongation, Type III is a pursuit type for relationship improvement, and Type IV is a perception type for family presence. Conclusion: The results of the study indicate that integrating multi-disciplinary curriculum development related to dignified dying and death education for students majoring in human service area are needed.