• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.3
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• pp.250-258
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• 2014

Due to recent industrial growth and development, there has been a high demand for light and highly durable materials. Therefore, a variety of new materials has been developed. These new materials include carbon fiber reinforced plastic (CFRP or CRP), which is a wear-, fatigue-, heat-, and corrosion-resistant material. Because of its advantageous properties, CFRP is widely used in diverse fields including sporting goods, electronic parts, and medical supplies, as well as aerospace, automobile, and ship materials. However, this new material has several problems, such as delamination around the inlet and outlet holes at drilling, fiber separation, and tearing on the drilled surface. Moreover, drill chips having a fine particulate shape are harmful to the work environment and engineers' health. In fact, they deeply penetrate into machine tools, causing the reduction of lifespan and performance degradation. In this study, CFRP woven and unidirectional prepregs were formed at $45^{\circ}$ and $90^{\circ}$, respectively, in terms of orientation angle. Using a high-speed steel drill and a TiAIN-coated drill, the two materials were tested in three categories: cutting force with respect to RPM and feed speed; shape changes around the input and outlet holes; and the shape of drill chips.

• Journal of Adhesion and Interface
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• v.20 no.2
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• pp.66-70
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• 2019

The surface of hydrophobic polypropylene (PP) fibers (spun-bonded fabric) was treated by an atmospheric plasma treatment method. These pre-treated hydrophilic PP fabrics were dip-coated in the aqueous poly(N-vinyl pyrrolidone) (PVP) solution. PVP layers on the surface of PP fiber were crosslinked by an irradiation of electron beam. The thickness of PVP hydrogels coated on the surface was easily controlled by changing the concentration of PVP in coating solution. The stepwise surface treatment, PVP coating, and hydrogel formation via electron beam irradiation were analyzed by the measurement of contact angle, scanning electron microscopy, and optical microscopy.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.2
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• pp.141-150
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• 2019

Despite increased evidence of bio-activity following far-infrared (FIR) radiation, susceptibility of cell signaling to FIR radiation-induced homeostasis is poorly understood. To observe the effects of FIR radiation, FIR-radiated materials-coated fabric was put on experimental rats or applied to L6 cells, and microarray analysis, quantitative real-time polymerase chain reaction, and wound healing assays were performed. Microarray analysis revealed that messenger RNA expressions of rat muscle were stimulated by FIR radiation in a dose-dependent manner in amount of 10% and 30% materials-coated. In 30% group, 1,473 differentially expressed genes were identified (fold change [FC] > 1.5), and 218 genes were significantly regulated (FC > 1.5 and p < 0.05). Microarray analysis showed that extracellular matrix (ECM)-receptor interaction, focal adhesion, and cell migration-related pathways were significantly stimulated in rat muscle. ECM and platelet-derived growth factor (PDGF)-mediated cell migration-related genes were increased. And, results showed that the relative gene expression of actin beta was increased. FIR radiation also stimulated actin subunit and actin-related genes. We observed that wound healing was certainly promoted by FIR radiation over 48 h in L6 cells. Therefore, we suggest that FIR radiation can penetrate the body and stimulate PDGF-mediated cell migration through ECM-integrin signaling in rats.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.201-206
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• 2021

Damage to the highly pathogenic avian influenza virus(H5N1) continues to increase, but there is a lack of antiviral research. In this study, we analyze antiviral properties on H5N1 by coating Cu/TiO2 photocatalyst on polyethylene films. The specimen was manufactured a photocatalyst master batch and coated both sides of the 3-layer polyethylene fabric at 280℃ from the extrusion coating machine. The results showed a 99.9% decrease in the Staphylococcus aureus and Escherichia coli. In particular, H5N1 type highly pathogenic avian influenza viruses, which is capable of human infection, has been found to decrease 99.9% within five minutes of contact with Cu/TiO2 films. Antibacterial effects of films coated with photocatalyst are known, but this study also confirmed the antiviral effects.

• Textile Coloration and Finishing
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• v.28 no.2
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• pp.109-117
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• 2016

Synthetic fabrics, such as nylon and polyester, were dyed with persimmon juice by using a padding mangle repeatedly. The mechanical properties of these synthetic fabrics were analyzed using the Kawabata evaluation system. The following findings were obtained from this investigation. As the number of repetitions of padding dyeing increased, the tensile energy per unit area and the tensile resilience of synthetic fabric remained almost unchanged, whereas the linearity of the load-extension curve of the synthetic fabrics increased. As the number of padding repetitions increased, the synthetic fabrics dyed with persimmon juice exhibited increases in thickness and weight. As the number of repetitions of padding treatment with persimmon juice increased, the values of stiffness, anti-drape stiffness, fullness, and softness also increased, whereas the flexibility with soft feeling, crispness, and scrooping sensation significantly decreased. The amount of coated persimmon juice on the surface of the fabrics increased after three repetitions of padding treatment with persimmon juice. Nylon and polyester fabrics were dyed evenly with persimmon juice treated using a padding mangle.

• Korean Journal of Human Ecology
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• v.22 no.5
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• pp.461-476
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• 2013

This study aims to provide practical information of both color and hands of cotton fabrics dyed with persimmon dye powder for natural dyeing fashion industries by investigating dyeing behavior and color gamut, by testing mechanical properties depending on color characteristics, and finally by evaluating dyeing fastness. As results, the persimmon dye powder obtained by extracting the fruits to final solid powder was found as containing tannin and it partially coated between and on fibers similarly to traditionally dyed one. The K/S values of non-mordanted fabric and two differently mordanted ones with Fe and Cu seemed to reach their equilibrium from 800, 800, and 600% (owf), respectively. Yellow-red was the only one hue shown while tones were various as pale (p), light grayish (ltg), soft (sf), dull (d), grayish (g), and dark grayish (dkg). In mechanical properties, the dyed fabrics with p and ltg tended to be less altered than undyed ones whereas d and d kg by higher bath concentrations could be applied to boxy silhouette owing to their increased stiffness and less stretchability. Although fastness to dry cleaning and stain was good, color change by washing and rubbing needed to be improved.

• Textile Coloration and Finishing
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• v.27 no.1
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• pp.35-49
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• 2015

This paper investigated optimum process conditions of coating yarn for awning fabric. For this purpose, the simulation for processability and yarn quality using SPSS statistics package was carried out, and PP/TPO and PET/PVC coating yarns specimens were made with variation of extruder temperature and feed speed of core yarn on the yarn coating machine for examining simulation result. It was revealed that optimum coating conditions of PP/TPO 1000d coating yarn were extruder temperature $150^{\circ}C$, and core yarn feed speed 400~500m/min. Mechanical property and thermal shrinkage of PP/TPO coating yarn made at this conditions were best and core evenness rates of these coating yarns by yarn compression tester were also superior, which was certified by SEM photograph. In addition, these experimental results were coincided with simulation results. It was found that, in PET/PVC coating yarn, yarn physical properties between 1500d and 1200d coated yarns were not shown any difference, and core evenness rates of these coating yarns were superior. It revealed and concluded that these simulated coating conditions are applicable to production field.

• Textile Coloration and Finishing
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• v.20 no.6
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• pp.82-86
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• 2008

Cooling function is definitely one of the most desirable attribute of clothing. In spite of the recent progress on phase changing material(PCM) research, the final products with sufficient amount of cooling capability have not yet to be developed in market. A new concept of cooling fabrics has been proposed by applying "Peltier effect" to textile materials. It occurs whenever electrical current flows through two dissimilar conductors; depending on the direction of current flow, the junction of the two conductors is absorbed or released heat. This effect has been tested on P-type and N-type conducting polymers. A P-type conductive polypyrrole coated fabric was synthesized by in-situ polymerization on plain weave PET to make conductive fabrics. And an N-type electrically conductive material was synthesized by treatment of MWNT and polyethyleneimine(PEI). A noticeable amount of temperature difference has been found on the fabrics.

• Textile Coloration and Finishing
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• v.19 no.1 s.92
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• pp.24-30
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• 2007

Heat storage/release system in textile is a useful tool to increase energy efficiency and enhance comfortable microclimate of clothing. Phase change materials(PCM) are used in regulating storage and release properties of thermal energy. To investigate the temperature regulating ability of fabrics with PCM microcapsule(PCMMc), Nylon fabrics were coated with PCMMc via wet processing and they were characterized by SEM, DSC and infrared thermal analyzer. Also, water moisture transpiration, water penetration resistance, peel strength and washing durability of the fabrics were assessed. The water vapor permeation and water penetration resistance decreased with increasing PCMMc content. In DSC analysis, it can be seen that the microencapsulated fabric showed both exothermic md endothermic phenomena at specific temperature. Peel strength was decreased with increasing PCMMc content.

• Textile Coloration and Finishing
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• v.30 no.2
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• pp.90-97
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• 2018

Hydrophilic reactive hot-melt polyurethane adhesive(HRHA) using a hydrophilic polyol having different molecular weight and NCO index was synthesized. This HRHA was synthesized using Polyethylene glycol(PEG) as a hydrophilic polyol, Polypropylene glycol(PPG) and Polycaprolactone diol(PCL) as hydrophobic polyols, and Methylene diphenyl diisocyanate(MDI) as an isocyanate. The changes in IR spectrum, viscosity and thermal properties of HRHA with different PEG molecular weights and NCO index were investigated, and the tensile strength and elongation of the HRHA casting film and the peel strength, moisture permeability and water pressure of the HRHA coated fabric were confirmed. In this experiment, as the molecular weight of PEG and NCO index increased, the adhesive strength, tensile strength, elongation and moisture permeability was increased but viscosity and Tg was decreased.