• Journal of the Korean Applied Science and Technology
• /
• v.26 no.4
• /
• pp.379-384
• /
• 2009

Epoxy resin based encapsulants are widely used in semiconductor packaging applications. Epoxy resin based encapsulants are often subject to crack or delamination during the reliability test due to the thermal stress caused by high modulus nature of epoxy resins. Epoxy functional siloxanes are often added into epoxy resin to reduce the modulus so that the thermal stress can be reduced. Epoxy functional siloxanes, additives for reduced modulus, were synthesized and added into the curable epoxy resins. The modulus and the coefficient of thermal expansion (CTE) were also measured to investigate the thermal stress and to see whether the epoxy functional siloxane adversely affects the CTE or not. As a result, around 26% to 72% of thermal stress reduction was observed with no adverse effect on CTE.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1833-1838
• /
• 2003

In the nuclear power plant, emergency core coolant system(ECCS) is furnished at reactor coolant system(RCS) in order to cool down high temperature water in case of emergency. However, in this coolant system, thermal stratification phenomenon can be occurred due to coolant leaking in the check valve. The thermal stratification produces excessive thermal stresses at the pipe wall so as to yield thermal fatigue crack(TFC) accident. In the present study, when the turbulence penetration occurs in the branch piping, the maximum temperature differences of fluid at the pipe cross-sections of the T-branch with thermal stratification are examine

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.10a
• /
• pp.555-556
• /
• 2012

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.11a
• /
• pp.509-512
• /
• 2003

Dehydration and micro crack thermal expansion occur in cement hydrates of concrete structure heated by fire for a long time. The characteristic of concrete exposed to high temperature can be analyzed from distribution of porosity and pore size. Porosity showed a tendency to increase irrespective of specimen types. This is due to both the outbreak of collapse of gel comprising the cement and a micro crack by heating. Porosity did not affect the variety of specimen and increased with the same tendency throughout every specimen. In addition, the deteriorate of compressive strength resulted from increase in porosity

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.186-186
• /
• 2010

The crack behavior in the ceramic Nd:YAG at a laser-diode end-pumped Nd:YAG ceramic laser was investigated. The fracture critical temperature difference of the ceramic Nd:YAG is about $355^{\circ}C$. The fracture of the 2 at% and the 4 at.% ceramic Nd:YAG occurred more than 14.9 W and 6.9 W pump powers, respectively, under lasing conditions.

• Proceedings of the KWS Conference
• /
• 2003.11a
• /
• pp.179-181
• /
• 2003

The present study focuses on the effect of geometrical discontinuity, strength mismatch, which can elevate plastic constraint due to heterogeneous plastic straining, and loading rate on the ductile crack initiation using two-parameter criterion. Fracture initiation testing has been conducted under static and dynamic loading using circumferentially notched round-bar specimens. In order to evaluate the stress/strain state in the specimens, especially under dynamic loading, a thermal elastic-plastic dynamic finite element (FE) analysis considering the temperature rise due to plastic deformation has been carried out.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.11a
• /
• pp.815-816
• /
• 2010

• Magazine of the Korea Concrete Institute
• /
• v.15 no.2
• /
• pp.108-112
• /
• 2003

• Magazine of the Korea Concrete Institute
• /
• v.15 no.6
• /
• pp.85-89
• /
• 2003

• Magazine of the Korea Concrete Institute
• /
• v.9 no.3
• /
• pp.38-47
• /
• 1997