• The Journal of the Korean dental association
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• v.16 no.12 s.115
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• pp.935-940
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• 1978

The purpose of this study was to evaluate the marginal sealing ability of 'Hi-Pol' Enamel Bond system. Using freshly extracted human teeth and 2% acquous methylene blue, the marginal leakage of dye in restorative materials such as 'Hi-Pol' Enamel Bond system, Hi-Pol, Adaptic, Nuva system, Epolite and Amalgam were investigated at 37℃ and under temperature cycling in range of 4℃-60℃. the results as follows; 1. All filling materials showed some degree of marginal penetration by 2% methylene blue dye. 2. 'Hi-Pol' Enamel Bond system revealed the least marginal penetration by 2% methylene blue as Nuva did at 37℃, but under temperature cycling in range of 4℃-60℃ it showed the greatest marginal penetration. 3. Hi-Pol restoration showed a tendency the similar to the other composite restoration. 4. Nuva system had the most effective marginal sealing ability either at 37℃ and under temperature cycling.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.861-864
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• 2002

Deformation of the specimen was investigated on hydrogen absorption-desorption cycling. In order to study this problem, the cold rolled palladium thin plate as the specimen had been used. By using the electrochemical method, the palladium plate specimen was cyclically hydrogenated in the 0.1 mol $H_2SO_4$ electrolyte. As results, it is noted that the thickness of the plate specimen gradually increased in increasing hydrogenation cycles whereas the width and the length decreased. Also, grains in the plate specimen were greatly deformed after hydrogenation cycling. But hydrogen absorption rate scarcely changed.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.577-580
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• 2007

The influence of flow rate has been investigated on the treatment efficiency of continuous cycling electrolytic process employing artificial and actual photographic wastewater which containing silver ion. For artificial wastewater, the treatment efficiency of process was found to rise ca. three times when the flow rate of wastewater was increased from 3 mL/min to 15 mL/min. The process efficiency was doubled under the same condition regarding actual wastewater. The effect of flow rate on the treatment efficiency was observed to be altered according to the metal ionic form and solution composition. The coefficient of mass transfer was estimated using model equation, which verified that the raised treatment efficiency at higher flow rate was due to the increased mobility of ionic species.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.4
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• pp.317-322
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• 2009

To investigate degradation mechanism of PEMFC operated with repetitive startup/shutdown cycling, i-V characteristics, impedance, cyclic voltamograms were measured. OCV decreased from 0.967 to 0.951 V while the cell voltage at 800mA/$cm^2$ from 0.657 to 0.563V, implying that the electrodes rather than membrane electrolyte was damaged during the cycling operation. Electrochemical analyses supported that the performance degradation could be mainly attributed to degradation of the electrodes such as a decrease in electrochemical active surface area rather than degradation of membrane.

• Journal of the Korean Ceramic Society
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• v.28 no.9
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• pp.712-720
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• 1991

The effect of cyclic compressive stress on fracture responses of Al2O3 was investigated under uniaxial stress cycling. Experimental data were obtained for Al2O3 tension specimens under uniaxial tension-unloading and tension-compression cyclic loading conditions. To investigate the effect of compressive stress on the crack growth, theoretical results from the crack growth rate were compared with measured stress vs. failure relations. At low stress level in tension-compression cycling, residual tensile strains were also observed about failure time.

• Journal of the Korean Ceramic Society
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• v.54 no.4
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• pp.314-322
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• 2017

This study investigates changes in the mechanical behavior, such as changes in indentation load-displacement curve, wear resistance and contact fatigue resistance of thermal barrier coatings (TBCs) by thermal cycling test and thermal shock test. Relatively dense and porous TBCs on nickel-based bondcoat/superalloy are prepared; the highest temperature applied during thermal durability test is $1350^{\circ}C$. The results indicate that the porous TBCs have relatively longer lifetime during thermal cycling and thermal shock tests, while denser TBCs have relatively higher wear and contact fatigue resistance. The mechanical behavior is influenced by sintering of the TBCs by exposure to high temperature during tests.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.153.1-153
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• 2001

This paper describes a development of rehabilitation training system for the postural balance control. A new rehabilitation training system, designated as a virtual cycling system, was developed to improve postural balance control by combining virtual reality technology with an unfixed bicycle. In this experiment, 20 normal adults were tested to investigate the influencing parameters of postural balance control. In order to evaluate the usefulness and the training effects of the system, several parameters Including path deviation, cycling velocity, cycling time, center of pressure, and head movement were evaluated and analyzed quantitatively. Also, to improve the effect of balance training, the visual feedback information related to the subject´s weight shift was ...

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.181.6-181
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• 2001

This paper describes a development of rehabilitation training system for the postural balance control. A new rehabilitation training system, designated as a virtual cycling system, was developed to improve postural balance control by combining virtual reality technology with an unfixed bicycle. In this experiment, 20 normal adults were tested to investigate the influencing parameters of postural balance control. In order to evaluate the usefulness and the training effects of the system, several parameters including path deviation, cycling velocity, cycling time, center of pressure, and head movement were evaluated and analyzed quantitatively. Also, to improve the effect of balance training, the visual feedback information related to the subject's weight shift was assessed to identify whether it was useful. It could be also known ...

• Journal of Korea Foundry Society
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• v.10 no.5
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• pp.399-407
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• 1990

The effect of thermal cycling and isothermal exposure on the high temperature microstructural stability of unidirectionally solidified $Al-CuAl_2$ eutectic composite has been studied. A coarsening procedures of lamellar eutectic structures were initiated at growth fault region because of diffusion through low angle boundary at this region. It was considered that thermally induced residual stresses produced by thermal cycling were high enough to increase the dislocation density in Al-rich matrix phase. However, it was also considered that dislocations generated by these high thermal stresses were annihilated at high temperature by stress relaxation. Consequently, the thermal cycling up to 1440 cycles between 20 and $520^{\circ}C$ did not affect the microstructural stability.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.829-832
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• 2002

Deformation of the specimens was investigated on hydrogen absorption-desorption cycling. In order to study this problem, the cold rolled and the annealed palladium thin plate as specimens had been used. By using the electrochemical method, the palladium plate specimens were cyclically hydrogenated in the 0.1mol $H_2SO_4$ electrolyte. As results, it is noted that the thickness of the plate specimens gradually increased in increasing hydrogenation cycles whereas the width and the length decreased. Also, Deformation of the cold rolled palladium specimen was lager than the annealed palladium specimen. And grains in the plate specimen were greatly deformed after hydrogenation cycling. But hydrogen absorption rate scarcely changed.