• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.9-12
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• 2005

Recently, research on the morphing wing is an interesting issue to develop the capability of the wing such as improving the lift and reduction of drag during the operation of an aircraft by changing the wing shape from one configuration to another. A more efficient weight reduction of the wing using smart or morphing wing concept can be achieved in comparison with the conventional flaps. In this study, it is investigated the behaviors of the morphing wing using Macro Fiber Composite (MFC) actuators. Generally, MFC is the piezocomposite actuator with the rectangular PZT fiber and epoxy matrix, and uses the interdigitated electrode to produce more powerful actuation in the in-plane direction. Furthermore, it can produce the twisting actuation as compared with the traditional PZT actuators. In the formulation, the first-order shear deformation plate theory is used, and finite element method is adopted in the numerical analysis of the model. Results show the characteristics of the static behavior of the morphing wing according to the change of the actuation voltage.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.547-548
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• 2009

Fiber reinforcement has been being widely used in concrete to enhance the mechanical properties and to reduce the micro-cracking caused by plastic and drying shrinkage. While researches has been focused on the benefits of fiber reinforcement, the properties of fiber reinforced concrete are strongly dependent on the type, shape and the amount of fibers in concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.37-38
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• 2016

In this study, it evaluate the coarse aggregate mixed effect to impact resistance performance of the fiber reinforced cement-based material. The type of fiber is Hooked-ended steel fiber, and mixed 1vol.% in concrete and cement composites. The impact experiment was conducted by using a spherical shape projectile diameter of 25mm to 170m/s speed and Impact resistance performance was evaluated by measuring the fracture grade, fracture diameter and depth.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.04a
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• pp.22-31
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• 1991

Machining with boring bars frequently induce chatter vibration because of the low stiffness and damping of cantilever shape of boring bars. To increase stiffness and damping, a carbon fiber epoxy composite boring bar was designed, manufactured and tested. The natural frequency of the carbon fiber epoxy composite boring bar in the free-free end condition was incerased more than 50% over that of the steel boring bar, and the damping of the carbon fiber epoxy composite boring bar was also increased 450%. The fundamental natural frequency of the carbon fiber epoxycomposite boring bar in the cantilever beam condition was found to be increased 20-30% over that of the steel boring bar in overhang length range 140-200mm. In machining S45C tapered workpieces, the limit of the overhang length of the steel boring bar was about 170mm in cutting speed 140m/min.

• Journal of Sericultural and Entomological Science
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• v.40 no.2
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• pp.163-168
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• 1998

Hydrolysis rate and activation energy of Antheraea pernyi silk fiber treated with HCI were examined. Thermal decomposition temperature and surface morphology were also investigated by using differential scanning calorimeter and scanning electron microscope. As the concentration of hydrochloric acid and the treatment temperature increased, the hydrolysis occurred more rapidly. The activation energy of Antheraea pernyi, 74.0 kJ/mol, was higher than that of Bombyx mori, 58.1 kJ/mol. As the concentration of hydrochloric acid increases, the activation energy of Antheraea pernyi decreased from 74.0 kJ/mol to 62.0 kJ/mol. The shape of acid-resistance fraction of Antheraea pernyi became more distroyed and was transformed from fiber to powdered form with an increase of hydrolysis rate. The thermal decomposition temperature of Antheraea pernyi was 360.8$^{\circ}C$ until the hydrolysis rate was 81.8 wt%, but ti decreased to 347.0$^{\circ}C$ when the hydrolysis rate was 93.8 wt%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.171-172
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• 2018

The purpose of this study is to confirm the adhesion performance of the three - dimensional forming fiber panels by the dimensional forming angle. As a result of applying the three dimensional surface shape to the back side of the fiber panel and testing the adhesion strength by the three dimensional forming angle, it was confirmed that the bonding strength of the specimens to which the dimensional molding was applied was higher than that of the non dimensional molding. In addition, the highest adhesion strength was confirmed in a specimen having a three-dimensional forming angle of 70 °.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.665-668
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• 2006

Concrete secondary product that use cement is increasing application from reason of shortening etc.. of construction period in construction site. Manufacture method of construction of this concrete secondary product there is hot-check method, direct spray method, press method, extrusion molding method etc.. Also, I am using reinforcement boating certainly in this process. In most case, We have used asbestos by reinforcement fiber until early 90s but use from human body hurtfulness controversy is felt constraint. Therefore, application of principal parts fiber is increasing. But, to replace asbestos, because must satisfy all lubricating ability, productivity etc.. class, it is the very difficult matter to replace asbestos. In this study, I wished to do Test about asbestos principal parts possibility at extrusion process to charge shape or form making test piece because mixs polypropylene fiber etc. by plan that replace asbestos in cement extrusion molding product and measures bending strength and elasticity.

• Wind and Structures
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• v.16 no.6
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• pp.541-560
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• 2013

The aim of the paper is to use optimization and advanced numerical computation of a sail fiber-reinforced composite model to increase the performance of a yacht under wind action. Designing a composite-shell system against the wind is a very complex problem, which only in the last two decades has been approached by advanced modeling, optimization and computer fluid dynamics (CFDs) based methods. A sail is a tensile structure hoisted on the rig of a yacht, inflated by wind pressure. Our objective is the multiple criteria optimization of a sail, the engine of a yacht, in order to obtain the maximum thrust force for a given load distribution. We will compute the best possible yarn thickness orientation and distribution in order to minimize the total fiber volume with some displacement constraints and in order to leave the most uniform stress distribution over the whole structure. In this paper our attention will be focused on computer simulation, modeling and optimization of a sail-shape mathematical model in different regatta and wind conditions, with the purpose of improving maneuverability and speed made good.

• Composites Research
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• v.16 no.2
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• pp.18-25
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• 2003

The tensile properties of short nylon6 fiber reinforced NR and SBR have been investigated as functions of fiber aspect ratio(AR), diameter ratio(DR), interphase condition, and fiber content. The tensile strength increased with increasing fiber AR(20 min.) and good interphase conditions. The short-fiber(DR=3 and AR=20 min.) reinforced SBR did not show the dilution effect for all interrhase conditions. And the short-fiber(DR=3 and AR=20min.) reinforced NR did not show the dilution effect except for the no-coating. The tensile moduli were significantly improved due to fiber AR. fiber content, and good interphase at same DR. The better interphase condition showed the higher pull-out force at same DR. Also, the stress analysis near the fiber end carried out using axisymmetric FEA to be convinced of the reinforcing mechanism. It is found that the fiber AR, interphase and DR have an important effect on tensile properties.

• Journal of the Korean Society of Costume
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• v.19
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• pp.83-103
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• 1992

This thesis researched the ritual dress of Korean new religions such as Suungyo, Mirubulgyo, Taejonggyo and WonBuddhism, According to kind, color, cloth and shape this thesis analyzed the ritual dress of them on the basis of its literatures. I. The results of the ritual dress of them through its literatures are as follows: 1. In case of Suungyo, there are Songwansonbok, Togwandobok, Pulmogwan, Ch'onui, Chap'ae , Yukhwangang, Pobdae, Hakp'yo and Kyonjang in its kind. In its color there are Huk, Cha, Hoe, Chahwang, Hong, Paek, Hwang, ROk, and Nam. Chemical fiber with one layer is used in its cloth. Its shape is made by a comprise between the feature of Korean dress, chuui and that of the existing dress of Confucianim, Buddhism and Taoism. 2. In case of Mirukbulgyo, Inhwag-wan, Chongbok, P'oui, Tae, Moson, Yomju and tanju are systematized in its kind. In its color there are Paek, Huk, ch'ong,Chok, Ok and Rok, Kongdan and chemical fiber with one layer are used in its cloth. Its shape has a symbolic form of Yu'Pul and son based upon Korean dress, Chuui. In its symbol Inhwagwan symbolized Confucianism and Chongbok Taoism and P'oui Buddhism. 3. In case of Taejonggyo, there are Chusabok, Sjhobok, Yewonbok, Chusamo, Yewonmo, Tae and Hwa in its kind. In its color there are Paek(main one), Nam, Huk, Chaju, Chok, Hwang and Hoe. Kongdan with both sides is elaborately used in its cloth. Its shape thken from Korean dress means the succession of the national spirit of the white-clad folk. 4. In case of won Buddhism, there are kybok and Pobrak in its kind. In its color there are Paek, Huk and Hoe---especially, both Hwangt'o and Hwang are used in Pobrak, Anyone can use cloth at his will. In its shape Kyoblk for man is Yangbok and Kyobok for woman is Tongch'ima and Chogori, a style of Korean dress. Pobrak is a form Tanryong worm with Rakja.