• Journal of the Korean Society of Visualization
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• v.18 no.1
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• pp.18-25
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• 2020

The droplet impact behavior is dominated by some parameters such as surface temperature, We number, surface and fluid property. Especially, Leidenfrost effect which prevents the contact between surface and droplet is very powerful phenomenon for determining droplet impact behavior. Due to this effect, the impact regime is divided into contact boiling regime and film boiling regime whether the droplet contact with the surface. Many studies have found that surface micro-structures which processed by surface processing are effective to overcome the Leidenfrost effect. In this study, droplet impact behaviors were compared using ethanol both on flat and laser-ablated Al surface. On the flat surface, impact regime was mainly divided by surface temperature. And there is key dominant parameter for each regime. On the laser-ablated surface, we could see changed impact regime and different impact behavior such as jetting and ejection of tiny droplets despite of same impact conditions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.930-935
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• 2005

In order to synthesis of the materials and modulus for floor impact sound reduction, we investigated effect on dynamic elastic modulus of floor impact sound reduction materials and module made by inorganic porous materials, EVA chips and so on. We find correlation property between dynamic elastic modulus and light-weight impact noise. And we measured the dynamic elastic modulus of materials and module for floor impact sound reduction. And we predicted reduction efficiency on floor Impact Noise of those. The dynamic elastic modulus is reduced by increase of filler contents and filler species. When the materials for floor impact sound reduction is consisted of l5wt% EVA Chip and l5wt% inorganic porous materials, its dynamic elastic material is the lowest. And when the module is consisted of PE (upper side), PS embossing board(lower side) and the materials for floor impact sound reduction(middle), its dynamic elastic material is the lowest.

• 한국IT서비스학회:학술대회논문집
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• 2006.11a
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• pp.143-150
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• 2006

본 연구는 한미FTA 체결이 우리나라의 소프트웨어 산업에 미치는 영향에 대해서 논의하였다. 소프트웨어 산업의 현황을 패키지소프트웨어, IT서비스, 디지털콘텐츠 등으로 구분하여 경쟁력 및 대미 수출입을 중심으로 분석하고, 관련된 한미 FTA 협상 영역중에 통신 및 전자상거래, 서비스, 저작권, 그리고 정부조달 영역 등에 대해서 각각 소프트웨어 산업 부분에 파급되는 영향과 시사점을 도출하였다. 결론으로는 우리나라 소프트웨어산업의 자체 경쟁력을 제고하고 미국 관련 시장에 폭넓게 진출하기 위한 전략의 관점에서 소프트웨어 산업 관련 정책상의 제안이 제시되어 있다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.30-31
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• 2015

High velocity impact of projectile generate local failure such as penetration, scabbing, perforation on concrete. It has been reported that local failure is affected by such as nose shape, mass of projectile. In this study, comparing and weighing the impact failure properties of concrete by high velocity impact test that using spherical nose and flat nose type projectile. As a result, It was considered that scabbing of Flat nose projectile reduced more than spherical nose projectile by dispersion of impact force.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.65-66
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• 2019

In this study, flexural strength and impact resistance were evaluated to investigate the fiber length effect of amorphous metallic fiber. As a result, in the case of 30AFRCC, cutoff behavior due to excellent bonding performance by large specific surface area has greatly influence on the flexural and impact resistance performance. In the case of 15AFRCC, the bonding efficiency is relatively low, because the specific surface area is smaller than that of 30AFRCC and the number of fiber is large, so the effect of improving the flexural and impact resistance performance is smaller than that of 30AFRCC.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2165-2171
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• 2002

Poly-butylene-terephalate(PBT) can be impact-modified by blending with ABS material. The effects of compatibilizers and ABS content on the mechanical properties of PBT/ABS blend were examined in this study. EPDM-g-GMA and polycarbonate(PC) were used as a compatibilizer. As the GMA content in EPDM-g-GMA increased, the tensile strength of PBT/ABS blend increased and the impact strength decreased. With increasing the EPDM-g-GMA content in PBT/ABS blend, the tensile strength and impact strength decreased. With PC compatibilizer, the particle size of ABS in PBT/ABS blend became smaller than that of the blend without compatibilizer and the particles were more evenly dispersed in matrix. The maximum impact strength of the PBT/ABS blend was observed in the range of 20~30% ABS content.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.3
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• pp.107-113
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• 2003

Microelectronics device performance and its reliability are directly related to and controlled by its constituent materials and their microstructure. Specific processes used to form and shape the materials microstructure need to be controlled in order to achieve the ultimate device performance. Examples of front-end and back-end ULSI processes, packaging process, and novel optical storage materials are given to illustrate such process-structure-property-reliability relationship. As more novel materials are introduced to meet the new requirements for device shrinkage, such under-standing is indispensable for future generation process development and reliability assessment.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.655-658
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• 2004

This study was performed to verify the possibility of the integrity estimation of the bridge substructure focusing on the dynamic property change of concrete pier with penetration depths using experimental modal analysis. As a result of the impact vibration test, it is found that scour reduces the stiffness of the foundation, and measurement the accelerance residue and natural frequency can be used for the estimation of the integrity index.

• Journal of the Korean Wood Science and Technology
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• v.36 no.1
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• pp.30-35
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• 2008

Degradation of mechanical properties of fire-killed Korean red pine has been investigated after death in 5 years period. Impact bending absorbed energy was the most sensitive property by elapsed time after forest fire. It is an indication of incipient decay of the wood and can be useful indicator to monitor any change of mechanical property of fire-killed tree after death. Degradation of mechanical properties was more pronounced in sapwood than heartwood. Impact bending absorbed energy was more reduced than any other properties in both sapwood and heartwood, while compressive strength was least impacted by elapsed time after forest fire. It is recommended that the fire-killed Korean red pine can be harvested in one year after the fire for industrial uses by considering decay and consequent changes of mechanical properties.

• Journal of Korea Foundry Society
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• v.35 no.3
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• pp.45-52
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• 2015

The effect of different C and Cr/Mo contents, which were varied within the range allowed in the relevant specification, on the mechanical and corrosion properties of A487 alloy cast steel were examined. The increase in strength level with increasing C content and the decrease in strength along with the increase in tensile elongation with decreasing Cr/Mo contents were observed in A487 alloys with different C and Cr/Mo contents. At room temperature, the decrease in Cr/Mo content was beneficial in improving the impact properties of A487 alloy, with no notable difference in absorbed energy with varying C content. The impact properties of A487 alloy at $-60^{\circ}C$, on the other hand, greatly improved with the increase in C and the decrease in Cr/Mo contents. The corrosion behavior of A487 alloys in 3.5% NaCl solution did not show any meaningful change with different C and Cr/Mo contents.