• 한국의류학회지
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• 제45권6호
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• pp.1035-1051
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• 2021

This study compares the strength properties of Jumchi-Hanjis dyed with 70% and 100% persimmon juice concentrations and undyed Jumchi-Hanjis. The Juumchi-Hanjis were made from Dakjis (mulberry papers), which were mixed with different ratios of fibers from paper mulberries originating in Korea and Thailand, including wood pulp from Canada. Research results showed that tensile, wet tensile, and bursting strengths of Jumchi-Hanjis dyed with 70% concentration were higher than those of undyed Jumchi-Hanjis. However, the tearing strengths of the dyed Jumchi-Hanjis were lower than those of undyed Jumchi-Hanjis. The wet tensile strengths of Jumchi-Hanjis dyed with 100% concentration were higher than those of dyed with 70% concentration. The increase and decrease of tensile, tearing, and bursting strengths depending on persimmon juice dyeing differed as per the mixing ratio of the raw materials of Jumchi-Hanjis. Dyeing with 100% persimmon juice concentration tends to be more useful than 70% to increase the tensile (MD) and wet tensile strengths of Jumchi-Hanjis containing only Korean mulberry fibers (90%) and wood pulp (10%) as raw materials. Dyeing with 100% concentration tends to be less useful than 70% to increase the tensile, tearing and bursting strengths of Jumchi-Hanjis with high proportions (90% or 60%) of mulberry fibers from Thailand.

• 대한조선학회논문집
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• 제36권4호
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• pp.95-104
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• 1999

강 구조물의 대형화에 기인하여 대형 해양구조물, 선박, 교량 및 고층 구조물에서의 극후판의 사용이 지속적으로 증가하고 있으며, 이런 경향은 앞으로도 계속될 것으로 생각된다. 그러나, 극후판을 사용하여 구조물을 시공할 때, 층상균열의 발생이 보고되고 있으며 이것은 극후판의 두께방향 중심부를 따라 분포하는 황, 인등의 불순 개재물 및 용접에 기인하여 발생하는 구속 잔류응력에 의하여 발생하는 것으로 알려져 있다. 연속 주조공법에 의하여 제조되는 극후판의 제조공정의 특성상, 층상균열의 발생은 회피하기가 현실적으로 어려우며, 따라서, 본 논문에서는 강구조물의 층상균열 발생의 감소 방안으로서, 금속학적 측면보다는 용접강도 측면에서 유한요소법에 기초한 전산 프로그램을 사용하여 최적 개선부형상 및 용접순서를 선정하고자 한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.1017-1022
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• 2001

The bend resistance of coated reinforcing bar is greatly influenced by adhesion strength of bar and coating materials and transformation of coating materials to the bar. Expecially, tearing state or a limited microscopic cracks are predicted on the inside and outside of bending angle because of adhesion strength and elongation is very different with types of polymer materials using bar coating, and these parts are accelerated corrosion as penetration of bar corrosion effects factor. In this study, cement modified polymer are prepared four types and differ from polymer cement ratio of 50% and 100%, coating thickness of 250$\mu$m and 450$\mu$m, coating number, curing age of 3, 7, 14 and 280days, and then tested bend resistance as bending angle $90^{\circ}$, $135^{\circ}$ and $180^{\circ}$ for observe the microscopic demage effect according as bar bend. From the test results, when is used cement modified polymer as coating materials of bar, St/BA is showed excellent bend resistance than a polyacrylic emulsion and SBR because of softness. But it is to need attention because as coating parts are pressed down and tearing, also experimental study is proceeded to corrosion potential on the inside and outside of coated reinforcing bar.

• 한국염색가공학회지
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• 제22권4호
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• pp.356-361
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• 2010

This study was aimed to investigate the antibacterial efficiency of silver nano-particles and the dyeing properties of a brushed warp-knitted fabric. The properties of the brushed warp-knitted fabric containing silver nano-particle by field production processes were evaluated by analyzing its silver contents, antibacterial activity, color difference, exhaustion curve, fastness and tearing strength. Bacterial reduction ratio amounts to 91.4 and 99.9 for Staphylococcus aureus and Klebsiella pneumoniae respectively. As the brushed pile length of its fabrics is longer, the exhaution rate of disperse dye becomes higher. The brushing process of its fabrics reduces the tearing strength. The results indicate that the brushed warp knitted fabric containing silver nano-particle can be a practically promising product.

• 한국응용과학기술학회지
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• 제11권1호
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• pp.45-52
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• 1994

For the purpose of producing emulsified fire proofing agent for synthetic fibers, 2,3-dibromopropylmonoamido orthophosphate[DP-AOP] and bis(2,3-dibromopropyl)monoamidoorthophosphate[$(DP)_{2}AOP$] were synthesized, and their structures were identified by instrumental analysis, respectively. Using three kinds of emulsifiers, O/W emulsified fire proofing agents, DPF and DPDPF, were obtained corresponding to DP-AOP and $(DP)_{2}-AOP$, respectively. Various synthetic textiles were fire-retardant treated by prepared DPF and DPDPF, and fire retardancy and tearing strength of the resulting products were tested. The results showed that as the concentration of fire proofing agents increased, fire retardancy increased, but the tearing strength much decreased, where the tendencies of DPDPF were deeper than those of DPF. But, since the fire retardancy appeared favorable in the range of $10{\sim}20wt%$ of DPDPF, DPDPF is proven to be a fire proofing agent useful for various synthetic textiles.

• 한국분말재료학회지
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• 제2권1호
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• pp.44-52
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• 1995

Effects of the extrusion temperature and die angle on the tensile properties of SiCIyAl composites in powder extrusion have been investigated. SiCP/Al composites were extruded at various extrusion temperatures (450, 500, $550^{\circ}C$) under the extrusion ratio of 25 : 1. The ram speed was maintained at 13 cm/min for all the extrusion conditions. The surface of the extruded rod appeared to be smooth without tearing at 450 and 50$0^{\circ}C$, whereas it was very rough due to tearing at $550^{\circ}C$. It was found that the tensile strength and elongation of the composites extruded at $500^{\circ}C$ are greater than those of composites extruded at $450^{\circ}C$ This is due to the easier plastic deformation of composite extruded at $500^{\circ}C$, compared with the composites extruded at $450^{\circ}C$. The effect of die angle was examined under 20=60, 120, $180^{\circ}$die angles at extrusion temperature of $500^{\circ}C$ under 25:1 extrusion ratio. The tensile strength of the composites extruded with 20=$60^{\circ}$approved to be higher than that of the composties extruded with 28 : 120 and $180^{\circ}$This is attributable to the higher extrusion pressure, which mixed composite powders could be densely consolidated at elevated temperatures, resulting from high friction force between billet and sliding surface of conical die.

• 한국의류학회지
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• 제30권3호
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• pp.481-486
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• 2006

한지를 의류용으로 사용하기 위한 시도들이 있었지만, 습윤상태에서 물리적 성질이 크게 감소한다는 문제점 때문에 많은 한계를 가지고 있었다. 따라서 한지의 습윤상태에서의 물리적 성질을 향상시키기 위해 내수성을 부여하고자, 실리콘 수지를 이용하여 한지에 발수가공을 행하였다. 패드-드라이-큐어 방법을 사용하여 처리하였고, 가공의 최적조건을 알아보기 위해 수지의 농도와 촉매의 농도, 큐어링 시간과 온도를 변화시켜 실험하였다. 한지의 발수도, 강연도, 방추도를 측정하였고, 습윤과 건조상태에서의 인장강도, 인열저항 마찰저항을 비교하였다. 그 결과 한지의 발수가공을 위한 최적처리조건은 실리콘 수지농도 40g/l, 촉매농도는 수지농도의 1/2인 20g/l, 큐어링 온도 160$^{circ}C$, 큐어링 시간 120초였다. 가공 후에도 한지의 유연성은 크게 저하되지 않았으며, 방추도는 약간 증가하였다. 가공 후, 건조상태에서의 인장강도, 인열저항은 큰 변화가 없었으나 내마모도는 증가하였고, 습윤상태에서의 인장강도, 인열저항, 내마모도 모두 증가하였다.

• Journal of Mechanical Science and Technology
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• 제15권1호
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• pp.35-43
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• 2001

Both tensile and tear properties of short-fiber reinforced Chloroprene rubber have been studied as functions of the fiber aspect ratio and fiber content. Both properties increased when both the fiber aspect ratio and fiber content were increased. The fiber reinforced rubbers exhibited maximum values of these properties at a fiber aspect ratio of about 300. When the fiber aspect ratio exceeds 400, the mechanical properties decreased with the fiber content because of the non-uniform dispersion of fibers. The tensile modulus was compared with the prediction by the Halpin-Tsai equations for randomly oriented cases. A bonding agent was used in the fiber treating process. It was found that the ultimate tensile strength, torque, tearing energy and tensile modulus of the rubbers with treated fibers were much higher than those with untreated ones.

• 한국의류학회지
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• 제13권4호
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• pp.357-369
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• 1989

The purpose of this study was to investigate the effects of treatment temperature and time on the, of easy-care and strength properties of the wet fixation processed rayon fabrics. Viscose rayon fabrics were treated with mixed resins of melamine formaldehyde (MF) and DMDHEU by one bath and two bath wet fixation processes. The MF/DMDHEU mixed resin concentrations were 50/100, 50/150, 100/100 and 100/150(g/1). Magnasium chloride was used as a catalyst. The wet fixation conditions were 24hrs at room temperature,20 mins at $75^{\circ}C$ and 5 mins at $105^{\circ}C$ Wet fixation processed fabrics did not show the difference in the resin add-one, DP ratings and wrinkle recovery angles by the different treatment temperatures and times. DP ratings were in the order of $105^{\circ}C>75^{\circ}C>room$ temp, in one bath and two bath wet fixation. Breaking and tearing strength of one bath processed fabrics showed in the order of $75^{\circ}C>room\;temp>105^{\circ}C$ The breaking strength of two bath processed fabrics showed in the order of $105^{\circ}C>75^{\circ}C>room$ temp. Tearing strength showed in the order of $75^{\circ}c>105^{\circ}C>room$ temp. Abrasion resistances were in the order of $75^{\circ}C>105^{\circ}C>room$ temp. in one bath and two bath processes.

• 한국공간구조학회논문집
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• 제10권2호
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• pp.127-134
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• 2010

막 구조는 자유로운 형태, 경량성, 내구성, 햇빛 투광성 및 균질성 때문에 전 세계적으로 현대 건축물에 다양하게 사용되어 왔다. 새로운 막 재료의 개발로 새로운 건축 구조설계에 대한 가능성을 열어가고 있다. 최근 주로 사용되는 막 구조의 지붕 재료에는 PVC, PVF, PVDF, PTFE 코팅 막재 및 ETFE 막재가 수로 사용되고 있다. 건축용 막은 내화성, 강도 부족, 인열강도, 내구성 및 탄성 등에 대한 몇가지 문제점들을 가지고 있다. 이러한 문제점들을 평가하기 위해서 본 연구에서는 PVDF 코팅 폴리에스터 막재에 대한 인장강도, 인열 강도 및 반복하중거동 시험을 실시하여 건축용 막재의 기초적인 역학적 특성을 분석하고자 한다. 막재의 탄성계수는 337.30~1257.63N/$mm^2$, 신율은 17.90~26.91%로 주어졌다.