• Journal of Biomedical Engineering Research
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• v.22 no.2
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• pp.151-156
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• 2001

A computer model of the musculoskelotal system that provides accurate prediction of muscle force and body movement trom the stimulation input is desired for the effective control system design in FES. This paper aims to investigate the fundamental properties of the gradual muscle force potentiation that was not included in the previous muscle models, for future development of a model that provides vetter prediction of FES-induced muscle force and body movement. Specifically, hou the muscle length was investigated. The experimental results showed that both the force increment ratio and the time-to-peak during electrical stimulation decreased with stimulatino frequency. When the muscle potentiation state was saturated by preceding stimulation. the force did not increase any more during additive stimulation. Muscle length significantly affected the force potentiation in such a way that the force increment ratio decreased with muscle length. A new model of the muscle potentiation based on these results is desired in the future.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.513-514
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• 2009

This study is to determine that lithium-silicate as reinforcement on surface for repairing concrete structure affects adhesive strength of mortar to recover the surface and of the strength for the obverse of concrete. these are focused on applying fields to the study.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.184-185
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• 2009

하이브리드 코팅 시스템을 이용하여 CrN 을 기초로 3성분계 코팅을 합성한다. 이번 연구는 C를 첨가한 음이온 고용경화와 Mo를 첨가한 양이온 고용경화의 영향이 미세구조와 기계적 성질에 미치는 영향을 알아보는 것이다. Cr-C-N 과 Cr-Mo-N 코팅은 23, 43GPa의 최대 경도 값을 가진다. 이 경도강화는 고용강화로 설명할 수 있다.

• Journal of agriculture & life science
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• v.46 no.1
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• pp.29-34
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• 2012

To examine possibilities to make use of woodceramics for the lower material of hot-floored ondol boards, woodceramics made from sawdust board with Pinus densiflora, put them in a wood frame and concrete block and heated them sending an electric current, and measured changes in surface temperature of a laminated floor board and a plywood floor board. As the sending an electric current to time passed, their surface temperature increased rapidly up to 20 minutes, and then gradually ascended. In terms of the surface temperature in the wood frame, the beginning temperature of a plywood floor board was higher than that of laminated floor one; however, as time passed, a laminated floor board's temperature rose, and after 60 minutes, it showed similar to the temperature of a floor board of lamination. On the other hand, the surface temperature in a concrete block showed that the laminated floor board was higher than the plywood floor board in both early and 60-minute later temperatures. With the lapse of time after switching off, the surface temperature of floor boards slowly dwindled up to 9 minutes, and from that time on, began to drop sharply. In terms of the descent speed of surface temperature, when woodceramics' surface temperature was adjusted at $70^{\circ}C$, the laminated floor board was the highest; when it was at $80^{\circ}C$, the plywood floor board was the highest, resulting in rapid descent speed of heat.

• Journal of the Mineralogical Society of Korea
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• v.25 no.2
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• pp.105-115
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• 2012

The consolidants have been widely used for the consolidation of decaying heritage stone surfaces. In this study, X-ray diffraction analysis, polarized and stereo-microscope and scanning electron microscope were used to study the surface characterization of granite, sandstone and marble, and to assess the efficiency and the effects of the developed condolidants in the field. The developed consolidants used in this experiment are 100%1T1G and 3%40nm/97%1T1G. The effects of consolidants are 3%40nm/97%1T1G${\gg}$100%1T1G in granite, 3%40nm/97%1T1G>100%1T1G in sandstone, and 3%40nm/97% 1T1G=100%1T1G in marble. The characteristics of rock surface when treated with consolidants show different result according to consolidantes type. This result of treating with consolidant can be used for the conservation of an decaying heritage stone.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.05a
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• pp.98-98
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• 2003

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.476-482
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• 2013

In this work, the effects of electrochemical oxidation of carbon fiber surfaces on mechanical interfacial properties of carbon fibers-reinforced polarized-polypropylene matrix composites were studied with various current densities during the treatments. Surface properties of the fibers before and after treatments were observed by SEM, AFM, XPS, and contact angle measurements. Mechanical interfacial properties of the composites were measured in terms of critical stress intensity factor ($K_{IC}$). From the results it was found that $O_{1s}$ peaks of the fiber surfaces were strengthened after electrochemical oxidation which led to the enhancement of surface free energy of the fiber, resulting in good mechanical performance of the composites. It can be concluded that electrochemical oxidation of the carbon fiber surfaces can control the interfacial adhesion between the carbon fibers and polarized-polypropylene in this composites system.

• Journal of Conservation Science
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• v.31 no.4
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• pp.351-360
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• 2015

This is the result of the study on the temporary fortifier using sublimation type Consolidate is Cyclododecane to prepare plan for reinforcement of the surface part that can be damaged during the dismantling of stone cultural heritages. To supplement the disadvantages of the existing reinforcement methods using intumescent urethane foam, Cyclododecane was diluted in solvent to reinforce the surface and inside desquamation, and after dismantling the framework, it sublimated by imposing heat of about $60^{\circ}C$. Such method can guarantee the strength needed for reinforcement of the damaged surface with outstanding reversibility of Cyclododecane being entirely sublimated. But, it shows big difference of effect according to the solvent, so it shall be diluted in petroleum ether or heated in a double boiler. Therefore, considering the working conditions at the site, it seems the most appropriate to use petroleum ether double boiler heating method for injection and filling of the desquamation part and temporary reinforcement processing with Cyclododecane diluted in petroleum ether for surface spraying.

• Composites Research
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• v.16 no.4
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• pp.74-79
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• 2003

Comparison of interfacial properties and microfailure mechanisms of oxygen-plasma treated poly(p-phenylene-2,6-benzobisoxazole(PBO. Zylon) and poly(p-phenylene terephthalamide)(PPTA, Kevlar) fibers/ epoxy composites were investigated using micromechanical technique and nondestructive acoustic emission(AE). Interfacial shear strength(IFSS) and work of adhesion, Wa of PBO or Kevlar fibers/epoxy composites increased by oxygen-plasma treatment. Plasma-treated Kevlar fiber shooed the maximum critical surface tension and polar term, whereas the untreated PBO fiber showed the minimum value. Microfibril fracture pattern of plasma-treated Kevlar fiber appeared obviously. Based on the propagation of microfibril failure toward core region. the number of AE events for plasma-treated PBO and Kevlar fibers increased significantly. The results oi nondestructive AE were consistent well with microfailure modes by optical observation in microdroplet and two-fiber composites tests.

• Analytical Science and Technology
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• v.22 no.3
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• pp.263-271
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• 2009

The purpose of metal artifacts conservation is recovering the original state of objects and preventing it from further corrosion. Four different consolidants are selected that are widely used for bronze objects conservation. This study found out the characteristics of thin film by various experiments and analysis for the bronze plates coated using each solutions. After a series of analysis, resin B and V showed good coating properties. However, the evaluation point suited to this purpose are adhesive strength, stability against yellowing and corrosion resistance. Therefore, resin B of four different consolidants could expect to get the most suitable consolidation effect for consolidation purpose.