• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.18-22
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• 2012

Photocurable binder for a transparent glass fiber composite was prepared with alicyclic methacrylate and fluorene-based diacrylate. ANOVA (analysis of variance) analysis was used to know main factors affecting the conversion of photocurable binder. It showed radiation intensity and photoinitiator (PI) concentration were main factors. The conversion of photocurable binder was simply increased with radiation intensity. Its increment however was abated with increasing PI concentration. We found that average conversion of the binder measured by FTIR-ATR was 87% when it was exposed to $5J/cm^2$ of UV dose with 5 wt% of PI. Oxime ester type PI was very effective to get a high degree of conversion, but it caused a yellowing problem. Owing to post-baking process, UV cured film showed an improved thermal stability by increase of conversion and removal of volatile organic compounds. TG% at $260^{\circ}C$ of film cured with 5 wt% of PI (TPO+MBF) and $5J/cm^2$ of UV radiation increased from 95.4 to 99.0% by post-baking at $230^{\circ}C$ for 5 min.

• Journal of Animal Science and Technology
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• v.47 no.3
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• pp.429-438
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• 2005

This experiment was conducted to determine the effects of feeding CLA and coumarin on the changes of biochemical composition of velvet antler and blood serum in spotted deer (Cervus nippon). There were no significant differences between treatments in crude protein, crude fiber, and crude ash contents of velvet antler. The content of fatty acid did not differ between treatments, although there were significant differences (P<0.05) in C16:0 and C20:0. The content of collagen was significantly higher (P<0.05) in control than those in CLA and coumarin treatments. There were no significant differences between treatments in the contents of amino acids. Some constituents of blood showed much differences in comparison of pre and post-experiment for all treatments. Feeding of CLA and coumarin was not influential on the chemical composition of velvet antler and blood serum.

• Textile Coloration and Finishing
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• v.9 no.3
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• pp.1-9
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• 1997

Plasma techniques permit modification of the surface layers of the substrate while maintaining its bulk properties. The use of plasma treatment on textile fibers and fabrics is very limited, however, the limitations, plasma treatments have been used to modify surface properties of textiles. In this study, multifunctional finish was performed by corona discharge technique for surface functionalization. Electron spectroscopy for chemical analysis(ESCA) was used to determine the ratios of carbon, oxygen, nitrogen, and phosphor at a 20$\AA$ sampling depth. K/S value and limiting oxygen index(LOI) value were used to obtain information on the effect of the finished fabrics. The mechanism of the flame retardancy was analyzed by the thermogravimetry-and the residue number. In ESCA, relative N1s intensity increased in case of mixtrure. The flame retardancy of the polyester and polyester/cotton fabrics treated with JA-6034 and JA-6050 was found to be operative mainly in the condensed phase mechanism. The multifunctional finish was better effect for the post treated finish agent.

• Textile Coloration and Finishing
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• v.30 no.2
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• pp.141-149
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• 2018

This study aimed to investigate the efficacy of eco-friendly leather dyeing by utilizing food wastes. Natural dyeing of eel skin was attempted using onion peels which have been used commonly for natural dyeing of textile fabrics. Eel skin is a by-product from fishery processing and is used mainly for making leather products. The colorant was extracted from onion peels in boiling water, concentrated, and freeze-dried. Dyeing of eel skin was carried out to study the effects of dyeing conditions, mordant type and mordanting method on dye uptake, color change, drape stiffness and colorfastness. The optimum dyeing conditions were $60^{\circ}C$ of dyeing temperature, 60min of dyeing time at 1:100($H_2O$ 90%: ethanol 10%) of bath ratio. The onion peels produced yellowish color on eel skin. The pre-mordanting was effective than the post-mordanting. As a result of the drape stiffness measurement, the Fe-mordanted sample was somewhat stiffer comparing to other mordanted samples. The light fastness of the non-mordant dye was excellent in 3-4 grade. Drycleaning fastness and rubbing fastness showed excellent results, but fastness was not significantly improved by mordanting.

• Smart Structures and Systems
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• v.4 no.3
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• pp.367-389
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• 2008

Shape Memory Alloys (SMAs) are unique materials with a paramount potential for various applications in bridges. The novelty of this material lies in its ability to undergo large deformations and return to its undeformed shape through stress removal (superelasticity) or heating (shape memory effect). In particular, Ni-Ti alloys have distinct thermomechanical properties including superelasticity, shape memory effect, and hysteretic damping. SMA along with sensing devices can be effectively used to construct smart Reinforced Concrete (RC) bridges that can detect and repair damage, and adapt to changes in the loading conditions. SMA can also be used to retrofit existing deficient bridges. This includes the use of external post-tensioning, dampers, isolators and/or restrainers. This paper critically examines the fundamental characteristics of SMA and available sensing devices emphasizing the factors that control their properties. Existing SMA models are discussed and the application of one of the models to analyze a bridge pier is presented. SMA applications in the construction of smart bridge structures are discussed. Future trends and methods to achieve smart bridges are also proposed.

• Journal of Advanced Navigation Technology
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• v.13 no.4
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• pp.559-565
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• 2009

The implementation possibility and increasement of transmission distance of 1 Tbps WDM transmission systems through the applying optical link configuration with inline dispersion management (DM) and optical phase conjugator (OPC) is investigated. When the considered optical link configuration is applied into $26{\times}40$ Gbps WDM transmission system and the optimal net residual dispersions (NRDs) depending on transmission length are decided, the effective transmission distanceis highly increased than that resulted in same system with fixed 0 ps/nm NRD in all transmission length. And, design rule of inline DM optical link is also shown through inducing the effective range of precompensation and postcompensation depending on transmission distance and launching power of WDM channel.

• Journal of the Korean Wood Science and Technology
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• v.45 no.6
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• pp.828-835
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• 2017

Airtightness of buildings is one of critical aspects of its energy performance. To build up references of airtightness of wooden houses built in Korea, blower door tests have been carried out in 42 houses since 2006. Causes of air leakage were investigated recently. The average value of air change rate was $3.7h^{-1}$ for light frame house and $5.5h^{-1}$ for post-beam construction at ACH50 (air change per hour at 50 Pa air pressure difference). Foam type insulation was more advantageous in ensuring building airtightness than glass fiber batt. Airtightness of wooden houses which were constructed after 2010 was improved to have less than $1.5h^{-1}$ of ACH50, threshold for application of artificial air change. The average air change rate of CLT (cross laminated timber) houses showed the lowest value, $1.1h^{-1}$, among the tested structures.

• Smart Structures and Systems
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• v.13 no.6
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• pp.943-957
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• 2014

When subjected to fatigue loading, the main failure mode of partially prestressed concrete (PPC) structure is the fatigue fracture of tensile reinforcement. Therefore, monitoring and evaluation of the steel stresses/strains in the structure are essential issues for structural design and healthy assessment. The current study experimentally investigates the possibility of using fiber Bragg grating (FBG) sensors to measure the steel strains in PPC beams in the process of fatigue loading. Six full-scale post-tensioned PPC beams were exposed to fatigue loading. Within the beams, the FBG and resistance strain gauge (RSG) sensors were independently bonded onto the surface of tensile reinforcements. A good agreement was found between the recorded results from the two different sensors. Moreover, FBG sensors show relatively good resistance to fatigue loading compared with RSG sensors, indicating that FBG sensors possess the capability for long-term health monitoring of the tensile reinforcement in PPC structures. Apart from the above findings, it can also be found that during the fatigue loading, there is stress redistribution between prestressed and non-prestressed reinforcements, and the residual strain emerges in the non-prestressed reinforcement. This phenomenon can bring about an increase of the steel stress in the non-prestressed reinforcement.

• Computers and Concrete
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• v.3 no.1
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• pp.65-77
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• 2006

This study reports the details of the finite element analysis of eleven shear critical partially prestressed concrete T-beams having steel fibers over partial or full depth. Prestressed concrete T-beams having a shear span to depth ratio of 2.65 and 1.59 and failing in the shear have been analyzed using 'ANSYS'. The 'ANSYS' model accounts for the nonlinear phenomenon, such as, bond-slip of longitudinal reinforcements, post-cracking tensile stiffness of the concrete, stress transfer across the cracked blocks of the concrete and load sustenance through the bridging of steel fibers at crack interface. The concrete is modeled using 'SOLID65'-eight-node brick element, which is capable of simulating the cracking and crushing behavior of brittle materials. The reinforcements such as deformed bars, prestressing wires and steel fibers have been modeled discretely using 'LINK8' - 3D spar element. The slip between the reinforcement (rebar, fibers) and the concrete has been modeled using a 'COMBIN39'-non-linear spring element connecting the nodes of the 'LINK8' element representing the reinforcement and nodes of the 'SOLID65' elements representing the concrete. The 'ANSYS' model correctly predicted the diagonal tension failure and shear compression failure of prestressed concrete beams observed in the experiment. The capability of the model to capture the critical crack regions, loads and deflections for various types of shear failures in prestressed concrete beam has been illustrated.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.41-44
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• 2001

Mechanical test of the Carbon Fiber Reinforced Plastics (CFRP) composite specimen was performed based on the ASTM code at the ambient and low temperature. Tension, compression in-plane shear, and inter-laminar shear properties of the composite laminates were evaluated experimentally using the Universal Testing Machine(UTM) system at the temperature of $24^{\circ}C$,$-76^{\circ}C$ , and $-196^{\circ}C$. From the test results it was found that the CFRP chosen for the Korea Superconducting Tokamak Advanced Research(KSTAR) magnet supporting post had smaller tensile strength and larger compressive strength at the low temperature than those of the ambient temperature because of material ductility.