• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1059-1064
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• 2012

In this study, tensile tests were performed on specimens that simulated the cold-bending and heat-treatment of pipe bends to understand the mechanical properties of pipe bends manufactured by cold-bending followed by heat-treatment for relieving residual stress. The strength and ductility of cold-worked materials were respectively found to be higher and lower than those of the parent material although heat-treatment was carried out to relieve residual stress. In addition, the increase in strength and decrease in ductility were proportional to the applied strain levels for cold-working. It was thus inferred that the intrados and extrados regions of pipe bends that were cold-bended and heat-treated show higher strength and lower ductility compared to the parent straight pipe and that the mechanical properties at the crown region are nearly the same as those of the parent straight pipe.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.10
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• pp.1655-1664
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• 2009

Chitosan is an environment-friendly and natural cationic polymer that can be used as a hair cosmetic additive. Healthy hair and damaged hair samples were experimented on according to treatment conditions using a water-soluble chitosan. Chitosan treated hair samples were studied on the physical and mechanical property changes. It is most effective when the water-soluble chitosan treatment was adjusted to the Neutral (pH6.8) or Acid (pH4.5). When the water soluble chitosan was treated at pH4.5, the tensile strength, tensile elongation, and elasticity of decolorized hair all increased. The virgin and damaged hair both changed into elastic and soft hair. The effect of chitosan treatment is more noticeable in the healthy hair than in the damaged hair.

• Korean Journal of Human Ecology
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• v.23 no.2
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• pp.317-328
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• 2014

In this study, differences of texture image and preference for men's suit fabrics according to mechanical properties, hand and fabric information were investigated. 55 subjects evaluated texture image and preference of 12 kinds of wool blended fabrics. For statistical analysis, t-test and pearson correlation coefficients were used. The results were as follows: Most of mechanical properties effected on texture images, and bending property and shearing property were effected on tactile preference and purchasing preference. For hand, objective hand values showed correlations with subjective texture images and preferences, but THV had almost no correlations. In sensory images according to presence of fabric information, fabrics were evaluated thinner, lighter, more pliable and smooth by cognition of wool blending ratio. For sensibility images, fabrics were evaluated more refined, intellectual, dignified and less practicable after recognize of wool blending ratio. In preferences, tactile preference was increased and purchasing preference was decreased after recognize fabric information. Therefore, significant differences of texture image and preference were observed according to presence of fabric information.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.7
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• pp.1193-1202
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• 2001

The goal of this research is to investigate the effect of fusible interlinings on the mechanical characteristics and appearance related values for the Lyocell fabrics. In this study, to establish optimum fusing conditions, peel strength of the fused fabrics depending on the fusing temperature, pressure and time was measured. Appearance related properties and mechanical characteristics of the fused fabrics ere determined. The reulst are as follows: In the fusing condition of $120^{\circ}C,\;3kgf/textrm{cm}^2$, 15sec, peel strength was excellent. Peel strength was excellent in the case of tencel/cotton fabric, with increasing cover factor of woven interlining, with twill and nonwoven interlining. Flex stiffness was increased in the case of tencel/cotton fabric, with increasing weight of woven interlining, with twill and nonwoven interlining. Drapability was excellent in the case of 100% tencel fabric, with decreasing weight of woven interlining, with plain and woven interlining. Crease recovery was excellent in the case of 100% tencel fabric, with increasing weight of woven interlining, with twill and woven interlining. Shear and bend properties were increased in the case of tencel/cotton fabric, with increasing weight of woven interlining, with plain and nonwoven interlining.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.441-445
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• 2005

In the resent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. But, no detailed researches between the thermo-dynamic property in Nitinol alloy have been done yet. In this study, the thermal property of high temperature Nitinol shape memory alloy were evaluated using differential scanning calorimeter(DSC). The structure property was investigated using X-ray diffraction(XRD). A dynamic mechanical analyzer(DMA) with three point bending mode was used to study storage and loss modulus of shape memory alloy according to the thirteen frequencies in the temperature range between 30 and $200^{\circ}C$. The effects of the temperature heating/cooling rate, the frequency on the damping capacity have been systematically investigated. Such a frequency and temperature changes also influenced significantly to the damping behavior of the shape memory alloy. It was also found that Nitinol exhibited high damping capacity during phase transformation.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_2
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• pp.435-441
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• 2021

This research was performed to study the effect of the Ni + Mo addition on the fatigue properties in 12Cr steel. After heat treatment of 12Cr steel and 12Cr-Ni-Mo steel, tensile tests, impact tests, hardness tests, and rotary bending fatigue tests were performed, respectively. The fatigue fracture surface was observed and analyzed using SEM and EDS. The fatigue limit of 12Cr steel was 554 MPa, which was 49 MPa higher than 505 MPa of 12Cr-Ni-Mo steel. Striations, which are the shape of the typical fatigue fracture surface, were observed at the fracture surface near the starting point of fatigue fracture in the 12Cr steel and 12Cr-Ni-Mo steel. However, unlike the case of 12Cr steel, 12Cr-Ni-Mo steel also had a mixed fracture surface with the fatigue and the ductile fracture surface. When brittle non-metallic inclusions exist near the starting point of fatigue failure, the crack propagation was further promoted and the fatigue life was drastically reduced.

• Fashion & Textile Research Journal
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• v.20 no.5
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• pp.600-607
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• 2018

Polypropylene fibers, while having many advantages such as light weight, sweat fast drying, water-repellent, drainage, thermal insulation, anti-static property has a drawback in dyeing. In recent years, the development of dyeable polypropylene fibers has expanded its value in the textile market. The purpose of this study is to fabricate composite spun yarns using polypropylene, acrylic, rayon and wool and to analyze tensile properties, uniformity characteristics, bending properties, hairiness, and surface shape according to the degree of fineness and blended ratio. The specimens consisted of 100% polypropylene spun yarn pp30, pp40 and ppa(pp/acrylic), ppr(pp/rayon), ppw(pp/wool), 5 altogether sed in this study. The results of the study are as follows. The breaking strength of polypropylene spun yarn blended with rayon and acrylic was higher than that of 100% polypropylene spun yarn. The polypropylene spun yarn is higher the fineness been shown to decrease the breaking strength and elongation. The bending properties of polypropylene spun yarns were in the order of ppa>ppr>pp40>pp30>ppw. The unevenness of ppw, ppr, and ppa was higher than pp40 and pp30. With the exception of ppw with crimp properties, pp30 and pp40 were found to have a hairiness index greater than ppr, ppa. In the microscopic photographs of polypropylene spun yarn, pp30, which had the highest hairiness index, was found to have a thick yarn and a large number of hairs, and ppw had hairs of 3 mm or more protruding elongated outwardly.

• Journal of the Korean Wood Science and Technology
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• v.25 no.4
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• pp.29-38
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• 1997

The effect and control of wood property of reconstituted composite panels for improved board properties by wood-waste materials and development of combination method for heterogeneous materials have been of interest to the wood science researchers. The purpose of this study is to consider the properties in relation to hot pressing conditions and to develope the optimum hot pressing condition with waste wood and waste tire for the manufacturing of composite boards. The study of composite boards for recycling of wood and waste tire is nothing up to the present. Physical and mechanical properties such as specific gravity, moisture content, swelling coefficient, modulus of rupture and modulus of elasticity in bending test were studied. The condition of 3-stage press time for the lowest moisture content of composite board was $4{\rightarrow}3{\rightarrow}3$ minutes. Specific gravity of composite panels was affected mainly by the amount of rubber chip. Because of the low rigidity and high elasticity in rubber chip, it is considered the composite panel was adequate material in the place of compression load, but not bending load. Therefore, it was concluded that a use of rubber-based wood composite panel is proper to the interior materials such as floor a room than exterior materials. From the test results, the most optimum hot pressing conditions were $4{\rightarrow}3{\rightarrow}3$ minutes for 3-stage press time and $45{\rightarrow}20{\rightarrow}5kg/cm^2$ for 3-stage press pressure. The rubber-based wood composite panel was very excellent in elasticity by combination of rubber chip in comparison with existing other wood-based materials. Therefore, it was considered that rubber-based wood composites can be applicable to every interior materials such as floor a room and will be expected to effective reuse and recycle of waste tires and wood-waste materials, and will be contribute to protection of environment pollution in earth.

• Geomechanics and Engineering
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• v.30 no.6
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• pp.525-538
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• 2022

This paper presents a more general model for T-shaped combined footings that support two columns aligned on a longitudinal axis and each column provides an axial load and two orthogonal moments. This model can be applied to the following conditions: (1) without restrictions on its sides, (2) a restricted side and (3) two opposite sides restricted. This model considers the linear soil pressure. The recently published works have been developed for a restricted side and for two opposite sides restricted by Luévanos-Rojas et al. (2018a, b). The current model considers the uniform pressure distribution because the position of the resultant force coincides with the center of gravity of the surface of the footing in contact with the soil in direction of the longitudinal axis where the columns are located. This paper shows three numerical examples. Example 1 is for a T-shaped combined footing with a limited side (one column is located on the property boundary). Example 2 is for a T-shaped combined footing with two limited opposite sides (the two columns are located on the property boundary). Example 3 is for a T-shaped combined footing with two limited opposite sides, one column is located in the center of the width of the upper flange (b₁/2=L₁), and other column is located at a distance half the width of the strip from the free end of the footing (b₂/2=b-L₁-L). The main advantage of this work over other works is that this model can be applied to T-shaped combined footings without restrictions on its sides, a restricted side and two opposite sides restricted. It also shows the deficiencies of the current model over the new model.

• Textile Coloration and Finishing
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• v.16 no.3
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• pp.22-30
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• 2004

The polyester fabrics were treated with the chitosan with various solubility in optimized treatment condition. The treatment method was discussed to be a high functional finishing for the polyester fabric to obtain the high moisture absorption and anti-microorganism property by evaluating the effect of the chitosan purification method on the yield and anti-microorganism property of the chitosan. On the other hand, soluble polyurethane was added to the chitosan treatment solution and/or plasma pretreatment was done. The addition of soluble polyurethane give a high add-on ratio as well as a linen like effect of treated polyester fabric. The results were as follows: 1. In the treatment of polyester fabric by the chitosan solution, a soluble PU resin and low temperature plasma treatment were done to obtain high binding force between the fabrics and the chitosan. The add-on rate and the moisture absorption ratio of the fabrics treated with the chitosan-PU after treated with the plasma slightly increased more than those of the fabrics treated with the chitosan only. 2. Anti-static property of the fabrics treated with the chitosan decreased rapidly with increasing of the chitosan concentration. The washing fastness of the fabrics treated with the chitosan-PU after treated with the plasma was better than those of the fabrics treated with chitosan only. The wrinkle resistance of the treated fabrics decreased constantly with the concentration of the chitosan. The bending rigidity of the treated fabrics increased greatly. On the treatment of polyester fabric under optimum condition, the microorganism reduction rate kept above 90％ after 10times launderings. 3. As the polyester fabrics which has flat yam was used as a weft yams were treated with the chitosan-PU as give a functional finishing effects such as durability, moisture absorption, anti-static and anti- microorganism property. Treated polyester fabric showed a good functional finishing effect and a linen like property.