• 한국의류학회지
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• 제25권2호
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• pp.350-357
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• 2001

In this study, seam strength, seam elongation and seam efficiency of polyurethane coated fabrics were examined under various sewing conditions using three kinds of fabrics, four kinds of sewing threads and three kinds of stitch lengths. And the sewability of polyurethane coated fabrics were evaluated by FAST system. The results were as follows: 1. Seam strength decreased with the increase of stitch length. The loop strength of sewing thread and the type of base fabric than the type of coated surface had an effect on seam strength. 2. Seam elongation also decreased with the increase of stitch length and was affected by the type of base fabric. The tensile elongation of polyurethans coated fabric had an effect on seam elongation. 3. Sean efficiency also was related to stitch length, the type of base fabric, and seam strength. The suitable seam efficiency was within 50%∼65% in which polyurethane coated fabric and sewing thread broke at the same time. Therefore PS thin and PPC thin sewing threads and 3mm stitch length were suitable to polyurethane coated fabrics. 4. The relaxation shrinkage(RS) of polyurethane coated fabric was smaller than the smallest value of control chart in FAST system. And the extensibility(E) and the shear rigidity(G) were larger than the largest value.

• 한국해양공학회지
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• 제20권1호
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• pp.1-6
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• 2006

The effects of microstructure on the damping capacity and tensile properties of 316L stainless steel were investigated. Increasing the degree of cold working, the volume fraction of $\varepsilon-martensite$ decreased after rising to maximum value at specific level of cold working, the volume fraction of d-martensite slowly increased and then dramatically increased from the point of decreasing $\varepsilon-martensite$ volume fraction. Increasing the degree of cold working, the behnvior of damping capacity is similar to that of the $\varepsilon-martensite$. After the damping capacity showing the maximum value at about $20\%$ of cold rolling, damping capacity was decreased with the volume fraction of $\varepsilon-martensite$. Tensile strength was proportional to the volume fraction of d-martensite, and elongation steeply decreased in the range low volume fraction of a'-martensite, then slowly decreased in range the above $10\%$ volume fraction of d-martensite. The damping capacity and elongation is strongly controlled by the volume fraction of $\varepsilon$ martensite with liner relationship. However, the effect of the volume fraction of d-martensite and austenite phase on the damping capacity was not observed. Tensile strength was governed by the volume fraction of d-martensite.

• 한국식품영양과학회지
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• 제30권3호
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• pp.494-499
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• 2001

어분으로부터 추출한 어분 단백질을 이용하여 가식성 및 생분해성 필름을 제조할 때, 어분 단백질의 추출 시간을 달리하여 제조된 필름의 수증기 투과도, 인장강도, 신장률 및 용해도의 변화를 측정한 결과는 다음과 같다. 어분단백칠 추출시간이 FMPI 필름의 수증기 투과도에 미치는 영향은 크지 않았다. 가소제로써 glycerol을 첨가한 필름의 수증기 투과도가 sorbitol을 첨가한 필름보다 높았다. 인장강도의 신장률은 어분 단백질의 추출시간이 증가함에 따라 증가하다가 1시간일 때 가장 높았으며 그 이상 추출시간이 증가함에 따라 감소 하였다. 총 용해물질의 함량과 수용성 단백질 함량은 어분 단백질의 추출시간이 증가함에 따라 감소하였다가 1시간일 때 가장 낮았으며, 추출시간이 1시간 이상 증가함에 따라 증가하였다. 필름의 수용성 단백질 함량과 인장강도와 신장률은 음의 상관 관계를 나타내었으며 신장률($r^{2}=0.62$)보다는 인장강도($r^{2}=0.83$)가 수용성 단백질의 함량과 밀접한 상관관계를 나타내었다.

• 한국압력기기공학회 논문집
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• 제19권1호
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• pp.11-19
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• 2023

Additive manufacturing technology, called as 3D printing, is one of fourth industrial revolution technologies that can drive innovation in the manufacturing process, and thus should be applied to nuclear industry for various purposes according to the manufacturing trend change in the future. In this paper, we performed tensile tests of 3D printed stainless steel 316L as-built specimens manufactured by two types of technology; DED (Directed Energy Deposition) and PBF (Powder Bed Fusion). Their mechanical properties (tensile strength, yield strength, elongation and reduction of area) were compared. As a result of comparison, the mechanical properties of the PBF specimens were slightly better than those of DED specimens. In the same additive type of specimens, the tensile and yield strength of specimens in the X and Y direction were higher than those in the Z direction, but the elongation and ROA were lower.

• 수산해양기술연구
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• 제29권2호
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• pp.117-123
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• 1993

In order to analysis the tensile properties of the high-tech fibers for fishing gear materials. tensile strength was tested on raw materials, single yarns and netting twines(plied yarns)made of nylon, kevlar 29 and techmilon respectively. The results obtained are as follows: 1. The tensile stress and tenacity of unknotted single yarns in dry and wet conditions were 3 to 3.5 times greater in the high-tech fibers than in nylon. But the elongation of the high-tech fibers was about 15% of that in nylon. 2. The tensile strength of knotted single yarns in dry and wet conditions was arranged in order of as follows : techmilon. kelver 29, and nylon. The ratio of knot strength to tensile strength, knot efficiency, was the highest in nylon. 3. The tensile strength of unknotted netting twines in dry and wet conditions was 2.3 to 2.5 times greater in the high-tech fibers than in nylon. 4. The tensile strength of knotted netting twines in dry and wet conditions was arranged in order of as follows : techmilon, kevlar 29, nylon. The knot efficiency was the highest in nylon.

• 접착 및 계면
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• 제20권1호
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• pp.15-22
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• 2019

Polybutadiene diol (PBD)과 isophorone diisocyanate (IPDI)의 반응을 통하여 이관능 우레탄 아크릴레이트 올리고머 (PB-UAO)를 합성하고, 여기에 삼관능 아크릴레이트 모노머 (Tris(2- acryloyloxyethyl) isocyanurate (TAOEIC), 또는 Trimethylolpropane triacrylate (TMPTA) 또는 Pentaerythritol triacrylate(PETA)), 단관능 아크릴레이트 모노머 (Stearyl Acrylate) 그리고 광개시제를 혼합한 후 이형필름 위에 코팅하고 자외선 경화를 통하여 감압 점착 필름을 제조하였다. 삼관능 아크릴레이트 모노머의 구조 및 함량에 따른 감압 점착제의 박리강도, 인장강도, 신율, 열안정성 및 흡습 특성의 변화를 고찰하였다. 삼관능 아크릴레이트 모노머의 함량이 증가할수록, 그리고 분자량이 작을수록 감압 점착 필름의 박리강도, 연신율 및 흡습율은 감소하는 경향을 보였으며, 인장강도 및 열안정성은 증가하는 것을 확인하였다.

• 열처리공학회지
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• 제36권1호
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• pp.7-14
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• 2023

We investigated the effect of multiple tempering on the microstructure and mechanical properties of AISI 4340 steel. The austenitized and quenched AISI 4340 steels were tempered at 550, 600, and 650℃ for 1, 2, and 4 h by single-tempering (ST). The multiple tempering was conducted for 4 h by double-tempering (DT, 2 h + 2 h), and quadruple-tempering (QT, 1 h + 1 h + 1 h + 1 h). As tempering temperature increases, yield strength and ultimate tensile strength decrease and elongation increases due to recovery and recrystallization of martensite and coarsening of carbides. At 550℃, as the number of tempering cycles increases, the yield strength and tensile strength decrease at the expense of fracture elongation. At 600 and 650℃, the yield strength and tensile strength increase with increasing the number of tempering cycles while fracture elongation maintains similar values. The multiple tempering at the same tempering time of 4 h improves the modulus of toughness at all tempering temperatures, which is presumed to be due to the change in carbide precipitation behavior by multiple tempering.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1994년도 박판성형기술의 진보
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• pp.11-23
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• 1994

Formability of sheet metals can be evaluated using tensile testing. Easily measured tensile properties such as yield strength, tensile strength, elongation, strain hardening exponent, strain rate sensitivity and plastic strain ratio are important parameters to evaluated the sheet formability. This paper briefly explains how these properties are related to deep drawability and stretchability. The plastic anisotropy of sheet metals is usually attributed to the crystallographic texture. However dislocation distribution may influence the anisotropy.

• 열처리공학회지
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• 제24권5호
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• pp.271-276
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• 2011

The effect of grain size on the deformation induced martensite transformation and mechanical properties in austenitic stainless steel with high amount of Mn was studied. a'-martensite was formed by deformation and deformation induced martensite was formed with surface relief. With increase of grain size, volume fraction of deformation induced martensite was increased. With the increase in degree of cold rolling, hardness, and tensile strength was rapidly increased with linear relationship, while, elongation was decreased rapidly and then decreased slowly. With increase of grain size, hardness and tensile strength was rapidly increased with linear relationship, while elongation was decreased rapidly. The hardness, tensile strengths, and elongation were more strongly influenced by deformation induced martensite than the grain size.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.193-197
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• 2002

In this study, the casting/forging process was applied to the Shift-Fork, a manual transmission part of automobiles. In the casting experiments, the effects of additives, Sr, Ti＋B and Mg, on the mechanical properties and the microstructure of a cast preform were investigated. When 0.03% Sr were added into the molten aluminum alloy, the finest silicon-structure was observed in the cast preform and the highest tensile strength and elongation accomplished. And when 0.2% Ti＋B were added into the molten Al-Si alloy, the highest values of tensile strength were obtained. The maximum hardness was in case of 0.2% Mg. In the forging experiment, it was confirmed that the optimal configuration of the cast preform could be predicted by FE analysis. To minimize the cost as the press size, the compact shape of preform was proposed to reduce the volume of flash. The modification of shape in designing preform was performed to attain a satisfactory performance in the areas where the mechanical strength were more required. By using FVM(Finite Volume Method) software, it was verified that a proposed casting design was available. To identify the relationship between effective strain and mechanical properties of the final forged product, the compression test was performed. As the result, the tensile strength and elongation of a cast preform were much higher than before forging. The minimum forging temperature was found 40$0^{\circ}C$ to save heating time.