• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.729-734
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• 1995

원자력용 316L강에 질소를 첨가한 경우의 고온 인장성질을 조사하였다. 온도가 증가하면 인장강도는 감소하다가 온도범위가 30$0^{\circ}C$~50$0^{\circ}C$에서는 일정한 값을 나타낸 후 급격한 감소를 나타내었고 연신율은 감소하다가 40$0^{\circ}C$에서 최소값을 나타낸 후 다시 증가하는 경향을 나타내었다. 질소를 첨가하면 인장강도증가와 함께 연신율도 증가하였다. 동적변형시효 온도구간에서 변형속도변화에 따른 인장강도 및 연신율의 변화는 매우 작다. 동적변형시효를 위한 활성화에너지를 구해본 결과 동적변형시효를 일으키는 원소는 Cr이다. 질소를 첨가하면 동적변형시효가 발생되는 온도가 고온 쪽으로 이동되었는데 이것은 질소가 Cr과의 상호작용에 의해 Cr의 확산속도를 낮추기 때문이다. 가공경화지수는 동적변형시효와 회복의 영향으로 40$0^{\circ}C$에서 최대값을 나타내었으며 이 온도는 연신율이 최소값을 나타내는 온도와 인장강도가 일정하게되는 온도와 일치하므로 강도강화기구는 동적변형시효로 판명되었다.

• 대한치과보철학회:학술대회논문집
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• 1999.11a
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• pp.83-83
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• 1999

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.83-89
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• 2000

The purposes of this study were to evaluate clinical applicability of resin modified glass ionomer cements and to determine the effect of salivary contamination on the tensile bond strength. Fourty extracted human permanent premolars were prepared lot bonding and standard edgewise brackets were bonded with Ortho-One, Fuji Ortho LC, Vitremer and Advance. Fourty extracted human permanent premolars were contaminated with saliva, dried and bonded with same materials above. The tensile bond strength was tested by Instron testing device aster storage in normal saline at ,$37^{\circ}C$ for 24 hours from bonding. The results were as follows : 1. The tensile bond strength of Ortho-One group was $7.68\pm1.76$, Advance group was $7.87\pm2.80$, Fuji Ortho LC group was $4.99\pm2.53$, Vitremer group was $2.80\pm0.88$ MPa. The tensile bond strength in contaminated condition of Ortho-One group was $4.12\pm1.67$, Advance group was $5.37\pm0.68$, Fuji Ortho LC group was $4.41\pm1.61$, Vitremer group was $2.60\pm1.10$ Mpa. 2. Salivary contamination did not affect the tensile bond strength when compared with the uncontaminated enamel group in Fuji Ortho LC and Vitremer (p>0.05) and there was great significant difference in the tensile bond strength of Ortho-One and Advance. 3. Advance, Ortho-One and Fuji Ortho LC seemed to have clinically a proper bond strength.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.4
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• pp.96-100
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• 1997

Tensile properties of carbon fiber reinforce composite laminates with non-woven carbon mat are evaluated in this paper. Composite laminates are made by inserting non-wovon carbon mat between layers, The specimens were cut and polished according to ASTM standard . Longitudinal and Transverse Young's modulus are obtained by tensile test. Young's moduli without non-woven carbon mat are compared with those with non-woven carbon mat. Longitudinal and Transverse tensile strength are also investigated. Experimental results show that the transverse Young's modulus of composite materials with non-woven carbon mat is about 10% higher than that of composite materials without non-woven carbon mat. Longitudinal tensile strength of composite materials with non-woven carbon mat is about 24% higher than that of composite materials without non-woven carbon mat. Transverse tensile strength and torughness also increase by inserting non-woven carbon mat between layers.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.536-538
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• 2011

In this study, the moisture absorption behaviors of the CNT reinforced unsaturated polyester composites were investigated along with exposure temperature and time. The tensile properties of the specimens were evaluated to identify the effect of absorbed moisture on the mechanical properties. The exposure temperatures of $25^{\circ}C$ and $75^{\circ}C$ were considered and the exposure time up to 600 hours was applied. According to the results, moisture absorption rate was increased as CNT content and exposure temperature were increased. The rate of decrease in tensile strength of the CNT reinforced unsaturated polyester composites was reduced due to the reinforcing effect of CNT compared to the unsaturated polyester resin.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.55-60
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• 2003

Case that long-fiber reinforced polymeric composites of fiber orientation situation of a direction state is J=1 that is direction of tensile strength of another state appeared highest. And theoretical tensile strength value of long-fiber reinforced polymeric composites board of fiber orientation situation of a direction state appeared similarly with tensile strength value that long-fiber reinforced polymeric composites board of fiber orientation situation of a direction state. Also, than case that efficiency of fiber orientation situation of long-fiber reinforced polymeric composites is J=1 in it is J=0.1 of fiber orientation situation effect of long-fiber reinforced polymeric composites about 60% high appear.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.9
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• pp.788-795
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• 2008

To understand the tensile behaviors of GFRP at low temperature, three types of specimen have been used in this study. Tensile properties and fracture mechanisms for three orthogonal orientations of plain weave glass fabric reinforced epoxy resin laminate were investigated at temperature range of about -30 to $15^{\circ}C$. The tensile properties of axial and edge type specimen decrease slightly with decreasing temperature to $-20^{\circ}C$. However, at $-30^{\circ}C$ the decreases in the tensile properties increased considerably. Below $-20^{\circ}C$, thickness type specimen showed a marked decreases in the tensile properties. It was obvious that the fracture manner of thickness type specimen was adhesive failure at above $-10^{\circ}C$ and a mixed adhesive and cohesive failure at below $-20^{\circ}C$.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.629-634
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• 1995

Zr-2.5 % Nb 합금 압력관에서 집합조직이 강도에 미치는 영향을 조사하여 기저면 성분(F)의 강화 효과를 분리하였으며 아울러 온도에 따른 강도의 변화를 조사하였다. As-received 압력관 재료의 상온 항복 강도는 인장 응력에 수직한 면에서 측정한 기저면 성분(F)에 대하여 $\sigma$$_{YS}$ =600 + 410 F 의 관계를, annealing 처리한 등축정 재료의 상온 항복 강도는 $\sigma$$_{YS}$ = 410 +310 F 의 관계를 따르는 것으로 나타나 기저면 성분이 주도적인 강화 효과를 갖는다는 것을 확인 할 수 있다. 따라서 Zr 합금의 항복 강도는 인장 응력에 수직한 면에서의 기저면 성분에 따라 좌우되며, Zr-2.5% Nb 압력관에서 길이 및 원주 방향에서의 항복 강도의 차이는 주로 기저면 성분의 차이 (F)에 의한 것이라고 결론지을 수 있다. $\alpha$-Zr 에서 슬립과 쌍정의 임계 전단 응력 및온도에 따른 변형 기구의 변화에 대하여 논의하였다.

• 대한치과보철학회:학술대회논문집
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• 1999.11a
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• pp.59-59
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• 1999

• Composites Research
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• v.13 no.1
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• pp.50-60
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• 2000

This paper presents an analytical method considering tensile strength enhancement in hybrid $Al_2O_3$ fiber/particle/aluminum composites(MMCs). The tensile strength and elastic modulus of the hybrid MMCs are even 20% higher than those of the fiber reinforced MMCs with same volume fraction of reinforcements. This phenomenon is explained by the cluster model which is newly proposed in this research, and the strengthening mechanisms by a cluster is analyzed using simple modified rule of mixtures. From the analysis, it is observed that cluster structure in hybrid MMCs increase the fiber efficiency factor for the tensile strength and the orientation factor for the elastic modulus. The present theory is then compared with experimental results which was performed using squeeze infiltrated hybrid MMCs made of hybrid $Al_2O_3$ short fiber/particle preform and AC8A alloy as base metal, and the agreement is found to be satisfactory.