• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.278-284
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• 1997

This study dealt with the flowing properties of the super flowing concrete for class F fly ash producted thermal power plant and the application for concrete industry. For this purpose, fly ash is analyzed for confined water ratio($\beta_p$)and the super flowing concrete is tested the flowing properties including flowing velocity, funneling time, height difference of box test and compressive strength. As the result, in order to satisfy the flowing properties of the super flowing concrete using class F fly ash, the optimum mixing conditions are determined water-bindrer ratio 37$\pm$2%, volume ratio of fine aggregates(Sr) 47$\pm$2% and coarse aggregates(Gv) 51$\pm$1%.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.177-185
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• 1997

The purpose of this study is to investigate the mechanical properties of super-workable concrete using O.P.C., blast-furnace slag, and fly ash respectively. For this purpose, after determining the optimum mix proportion of super-workable concrete according to unit weight of binder and percentage of fine aggregate respectively, mechanical properties of super-workable concrete such as compressive, tensile and flexural strength as well as elastic modules were tested and analyzed. Also, the mechanical performances of super-workable concrete were compared with those of high-strength concrete with equal mix proportion of concrete. As a result, super-workable concrete have an excellent mobility, placeability, and segregation-resistance, but the strength of super-workable concrete was shown to be somewhat lower than that of high-strength concrete with equal mix proportion of concrete.

• Journal of the Korea Concrete Institute
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• v.11 no.4
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• pp.73-81
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• 1999

The present study is to examine the ACI code equations for computing the unbonded tendon stress at flexural failure of prestressed beams. The equations examined for their validity are Eq. 18-4 and Eq. 18-5 of the ACI 318-95. Since the possibility of overestimation was expected with the equations, a numerical study, first, was carried out with influential variables included. From this study, it was found that amount of reinforcements, effective prestress, location of tendons, and loading type may affect the overestimation of the unbonded tendon stress. Then, an experimental study was carried out with those variables. A total of 8 specimens was tested to prove the theoretical findings as well as the effect of those variables. As a result. it was proven that the ACI Code equations can overestimate significantly the unbonded tendon stress for certain cases.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.345-348
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• 2005

This paper presents the result of adiabetic temperature rise and fundamental properties of concrete combining admixtures. According to results, difference of setting time with I5.5hours is observed between S-P and R-F30 mixture. Based on the adiabetic temperature rise test, 8$^{circ}C$of heat producted occurs between E-P and R-F30 mixture. is applied to estimate the temperature rising under adiabetic curing condition, which exhibits closer consistency with tested value. The function mentioned above can account for the effect of dormant period in hydration process at early stage on hydration heat production. It reveals that the consideration of placing layer based on the mixture adjustment(E-P mixture at top layer and R-F30 mixture at bottom layer) in mass concreting will contribute to reduce hydration heat as well as alleviate tensile stress discrepancy between placing layer.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.493-497
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• 2010

Real time coordinate conversion of vessel was realized, we developed motion control algorithm of DC Servo Motor. We made servo control circuit and PCB, also We developed the system using 3-axis Gyro Sensor based Servo Motion Controller. For ship's movement simulation, we made the ship simulator of 6 degree of freedom. With a mounted camera on developed simulator, We tested the desired ship's movement, and the desired result of error tolerance was obtained.

• Journal of electromagnetic engineering and science
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• v.8 no.4
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• pp.153-157
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• 2008

Most of malfunctions in electronic equipment or systems controlled by processors is occurred by the differential- and common-mode noises, and the electrical fast transient (EFT). The International Electrotechnical Commission (IEC) has prepared the dummy signal to test the immunity level of the equipment. For the countermeasure against the differential- and common-mode noises, and the EFT, we designed, fabricated, and tested a new electromagnetic compatibility (EMC) filter, which is composed of feed-through capacitors and ferrite beads with high permeability. As a result, the filter showed excellent differential- and common-mode noises filtering, and immunity improving characteristics over the frequency band from 30 MHz to 1.5 GHz and 1.8 GHz, respectively.

• Journal of electromagnetic engineering and science
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• v.13 no.2
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• pp.104-112
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• 2013

A novel miniaturized artificial magnetic conductor (AMC) is proposed for dual-band operation. An AMC unit cell that employs four slots in the metallic patch is used to achieve miniaturization as well as easy control of the second/first resonant frequency ratio, which can be varied from 1.5 to 3.26 by simply changing the slot shape for a given metallic patch size. A dual-band antenna composed of a wideband monopole suspended over the proposed AMC surface is designed and tested to validate this approach. The measurements result in a satisfactory and good matching condition for the dual-band antenna.

• Journal of Korean Academy of Nursing
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• v.7 no.1
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• pp.112-120
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• 1977

This study attempts to predict nurses'clinical performance from entrance examination of university and college achievements after graduation. This is based upon a survey study, 49 nurses in Yon Sei Medical Center after graduation of college of nursing. Correlation of college achievements, clinical performance and variables of nurses'clinical performance are produced using Pearson's Product moment correlation coefficient significance of correlation tested by T- test. The result of the study were as follows; 1. Clinical performance of the college achievements is the best efficient variables in predicting the nurses'clinical performance after graduation and next theory scholastic total achievements and entrance examination the last. 2. There are significant correlation among nurses'clinical performance rating variables as nursing ethics, nursing skills, achievements, attitude, the state of health.

• Journal of Ocean Engineering and Technology
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• v.10 no.2
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• pp.35-41
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• 1996

This paper is aimed to solve local buckling problem that can frequently occur when the high speed ship's hull of sandwich structural type is crushed by rarbour and cargo. Experiment is performed on 36 specimens cut of 4-plates that made of sandwich type(Kevlar-Epoxy, Klegecell foam) and 16-Edgewise compressive test specimen, 16-Flatwise test specimen were tested by A.S.T.M. test method. The result of this study is analyzed and compared in test method and test jig to perorm Edgewise compressive test and Flatwise test.

• Journal of Ocean Engineering and Technology
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• v.2 no.1
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• pp.170-175
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• 1988

A study on the dynamic vibration absorber with coil spring and oil damper was carried out both theoretically and experimentally. A main mass is attached to a foundation using coil spring and oil damper. A harmonic motion was applied to the foundation. The effects of the dynamic vibration sbsorber are theoretically summarized in graphs, and tested on a vibratory model for the isolation of actual mechanical vibration. As a result, the first resonance amplitude ratio increased and the second resonance amplitude ratio decreased as the absorber spring constant increased. When the absorber mass increase, the first resonance amplitude ratio is decreased and the second resonace amplitude ratio is increased.