• 소성∙가공
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• 제17권8호
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• pp.570-578
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• 2008

A flexible forming apparatus is composed a number of punches which have spherical pin tip shape instead of conventional solid die. The flexible forming tool consisted of punch array in a matrix form was proposed as an alternative forming method to substitute the conventional line heating method which use heat source to induce residual stress along specified heating lines. In this study, application of the flexible forming process to the small scale curved plate forming was conducted. Numerical simulations for both solid and flexible die forming process were carried out to compare the shape of the products between flexible and conventional die forming process. In addition, spring-back analysis was conducted to figure out the feasibility of the flexible forming process comparing with the die forming process in view of final configuration of the specimens. Moreover, experiment was also carried out to confirm the formability of the process. Consequently, it was confirmed that the flexible die forming method has capability and feasibility to manufacture the curved plates for shipbuilding.

• 한국의류학회지
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• 제28권6호
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• pp.819-829
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• 2004

This study was carried out to suggest a new swimsuit fabric with improved durability, comfort and appearance, by employing PTT(polytrimethylene terephthalate). Objective and subjective performances of newly woven PTT/PU (polyurethane) blend fabric were estimated and compared with nylon/PU(80/20) which is currently used for swimsuit. According to the questionnaire, the most serious problems of swimsuit fabrics were such that they were easily degraded by chlorinated water and this made fabric inelastic and transparent. After exposure to the chlorinated water, PTT blend fabrics showed higher retention of breaking strength, bursting strength, elastic recovery and crystallinity. suggesting that PTT/PU(87/13) was the most excellent material in durability. PTT blend fabrics absorbed less water and dried faster than nylon/PU and thus PTT/PU(87/13) was shown to be the best in respect of comfort. All of the specimens used in this study exhibited satisfactory colorfastness to sea water, chlorinated water and light except that nylon/PU(80/20) represented weak colorfastness to chlorinated water. From the subjective wearing sensation test, PTT/PU(82/18) was shown to posess the best wearing sensation. From the overall evaluation or objective and subjective properties, PTT blend fabrics exhibited superior performances to nylon/PU(80/20), suggesting that they can be successfully used as a new durable and comfortable swimsuit fabric.

• 한국의류학회지
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• 제27권1호
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• pp.40-47
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• 2003

This paper discussed the assessment of hand of Tencel denim fabrics finished by enzymatic hydrolysis. The subjective hand and the preference of Tencel denim fabrics were evaluated using the developed scale. The factors affecting consumers taste for Tencel denim fabrics were analyzed by statistics using SAS program. Also, the effects of cellulase treatment on the properties of Tencel denim fabrics were evaluated by the subjective hand measurements. The results are as follows: As the weight loss increased. fabrics were evaluated as finer, smoother, softer, warmer, more refined (surface properties), more compact and weaker (durability), more flexible, flossier, lighter, softer, thinner (sense of weight), more elastic, and less wrinkly (shape recovery). Fabrics were evaluated to have the dry touch regardless to the rate of weight loss (moisture properties). Overall hand preference of Tencel denim fabrics was in the side of not preferred. Hand of Tencel fabrics seems not to appeal to Korean people. Color preferences were not significantly different among five groups. The correlations between subjective hand and preference showed that fine, smooth, flexible, warm, refined, loose, soft, dry touches were preferred in Tencel denim fabrics.

• 수산해양기술연구
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• 제16권1호
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• pp.23-26
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• 1980

The pure polypropylen rope has been used for the head rope, and the lead cored polypropylen rope for the ground rope in the anchovy boat seine. These ropes revealed the disadvantage that deforms the net shape due to their elongation. Te improve the disadvantage, authors developed the rope of new construction which is cored by wires and wrapped by polypropylene fibers, 20mm in diameter for the head rope and 40tnm for the ground rope. To compare the physical properties of the improved rope with the conventional ones, some factors are valued and the following results are found. 1. The improved ropes rev~al some disadvantages, such as the head rope is heavier, the ground rope lighter, and both of them are stiffer than the conventional ones, contrary to the required condition of ropes) However no special difficulties are found in practical use. 2. The improved ropes display much advantages, such as elongation is 30 percent less, breaking strength is 35 precent greater, and elastic recovery is 10 percent greater than the conventional ones. Thus, it is considered that the improved ropes are more suitable for the head rope and the ground rope of the anchouy boat seine net than the conventional ones.

• 한국정밀공학회지
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• 제25권1호
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• pp.99-107
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• 2008

There are being a lot of studies for achievement of high speed Dehydration, high-strength and Lightweight of washing machine in the latest washing machine business. It is essential that strength of mechanical press-Joining (MPJ) for spin drum is improved to attain that target. MPJ of spin drum is composed of seaming and caulking process. Because Seaming process of MPJ has various design factors such as thickness, bending radius, seaming width, caulking press width and the dynamic factor such as multistage plastic working, elastic recovery, residual stress, the optimum conditions can't be easily determined. Using a design of experiment (DOE) based on the FEM (Finite Element Method), which has several advantages such as less computing, high accuracy performance and usefulness, this study was performed investigating the interaction effect between the various design factor as well as the main effect of the each design factor during drum MPJ and proposed optimum condition using center composition method among response surface derived from regression equation of simulation-based DOE.

• 한국의류학회지
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• 제6권2호
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• pp.9-15
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• 1982

This study was conducted to examine the relation between the clothing materials and the garment's ease under wearing condition. Wearing test of slacks in the same pattern which were made of 3 woven fabrics and 1 knitted fabric have teen carried out. Subjects were 5 female students. Some physical properties of these fabrics were investigated. The following results were obtained. 1, By analysis variance with the results of sensory test which was tested by paired com-parison method, it was obtained that the effect of materials on the garment's ease were significant at the $1\%$ level on every part of stacks and posture of subject. It indicates that there is a difference of materials from materials in garment's ease. 2. Significant at the $5\%$ level among the materials. Jersey and Jean were looser than the other two materials. Clothing materials have considerable effect on the garment's ease of slacks, therefore it was noticed that the ease of slacks must have considered the clothing materials. It is more necessary in working dress. 3. Elastic recovery of width was more contributive to garment's ease of slacks than any other physical properties.

• 한국의류학회지
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• 제31권1호
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• pp.77-84
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• 2007

The purpose of this study was to investigate and to compare the performances of silicone laminated materials sold for swimming cap in market, to get the basic data for product development. We selected 4 specimens and tested their air permeability, waterproofness and breathability. We also tested the physical and mechanical properties of the specimens using KES system. Silicone-laminated material was not bursted on high hydraulic pressure since silicone membrane gave waterproofness while PU/Polyester substrate gave elasticity. It didn't have air permeability and breathability at all. Any toxic materials such as Formaldehyde, Deldrin, PCP, Amin, TDBPP were not detected in silicone-laminated material and other materials. Silicone-laminated material had higher stretchability with the low force but it had lower elastic recovery and shape stability comparing to PU laminated material. It had lower flexibility than PU laminated material. It had lower unrecoverable amount in shearing direction. Friction coefficient was higher in silicone-laminated material than PU laminated material due to its surface stickiness. It was compressed easily and its compression resiliency was higher with compared to PU laminated material.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.201-204
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• 2008

In this paper, several process parameter studies of the manufacturing process of the steel cords are carried out to verify the relation between the process parameters and the residual stresses on the steel cords. At first, the finite element analysis of the drawing process is performed and the residual stress distributions with respect to the wire material and the area reduction ratio are obtained. The residual stress of the drawn wire is imported the finite element analysis of the twisting process as an initial stress. After that a parameter study of the twisting process is carried out. The process parameters are the applied tension, the over-twisting angle and the tensile strength of the drawn wire. Based on these studies, the optimum values of the process parameters which can remove or reduce the undesired residual stresses are determined. The optimum value of the process parameters are confirmed by the finite element analysis of the elastic recovery process of the steel cords. Finally, the finite element analysis of the roller straightening process is done to study the variation of the distribution of the residual stress before and after the process.

• 대한기계학회논문집A
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• 제29권1호
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• pp.132-138
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• 2005

In heavy industrial fields such as power plant and chemical plant, it is often necessary to restore damaged part of large machinery and structure which is installed in the hazard working place. In this paper, to estimate stress distribution which occurs during damage and restoration of cylindrical beam structure, the finite element technique has been used. A finite element model was verified by experiment for non deformed cylindrical beam structure. The displacements and elastic recovery have an excellent agreement between experiment and finite element analysis. The variations of stress distribution on deformation and restoration procedure for surfaces have been examined. The maximum von Mises stress appears in the surface for deformation and restoration procedure. In deformation procedure, the maximum stress occurs in the vicinity of support body. In restoration procedure, the maximum stress occurs in the vicinity of the fixing body. The fixing body allows avoiding stress concentration in adjacent support structure boundary.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2019년도 춘계종합학술대회
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• pp.385-386
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• 2019

본 연구의 목적은 균형에 이상이 있는 20대 정상 성인에게 혈류제한성 탄력밴드 훈련 적용 시 균형능력 회복에 미치는 효과를 알아보고자 하였다. 12명의 남성을 대상으로 대조군(n=6), 실험군(n=6)으로 무작위할당하였다. 두 군은 고강도 축구경기를 통한 균형능력 손상 유발 후 실험군은 1주일 3회 1시간씩 4주 동안 혈류제한성 탄력밴드 훈련을 실시하였고, 대조군은 아무런 훈련을 실시하지 않았다. 모든 대상자는 경기 전, 경기 후, 경기 4주 후에 정적 및 동적 균형을 측정하였다. 연구 결과, 정적균형에서 대조군은 경기 전으로 유의한 회복을 나타내지 않았으나, 실험군은 유의한 회복을 나타냈다. 동적균형에서는 대조군과 실험군 모두에서 유의한 회복을 나타냈다. 혈류제한성 탄력밴드 운동은 단기간에 효율적으로 근력을 향상시킴으로써 균형능력 회복에 긍정적 영향을 줄 수 있다고 판단된다.