• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2661-2665
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• 2011

In order to evaluate the structural integrity of a GFRP composite bogie frame due to flying railway ballast, the low velocity impact test and compressive test after impact was conducted for glass fiber/epoxy 4-harness satin woven laminate composites applied to skin part of a bogie frame. The impact test was performed using a instrumented impact testing system with energy levels of 5J, 10J and 20J and the designed impactor based on typical railway ballast shapes such as sphere, cube and cone to simulate the ballasted track environments. The compressive strength was tested to according to ASTM D7137 to evaluate the degradation of mechanical property of impact damaged laminate composites. The results showed that the damage area and the degradation of compressive strength after impact for laminate composites was increased with increase in impact energy for all ballast shapes and was particularly most influenced by cone ballast shape.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.418-425
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• 2022

For a commercial building, property managers play an important role in maximizing the benefit by reducing cost and increasing revenue in the operation and maintenance phase of the building. However, most of property managers are spending their time in monitoring facility managers who have little impact on cost reduction and maximization of operating profit. The industry practitioners have difficutlty in increasing the efficiency of thier work due to this work environment. In addition, both property managers(PMr) and facility managers(FMr) are dependent on the paper drawings and manuals, which can worsen the inefficiency and human errors are inevitable. This study aims to contribute to improvement of the current practice by developing a novel algorithm that autmatically links the facility information with 3D model, which can provide an efficient property management for commercial buildings.

• 한국재료학회지
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• 제15권1호
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• pp.19-24
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• 2005

For the good combination of high-temperature strength, toughness and creep property, $9-12\%$ chromium steels are often used for gas turbine compressors, steam turbine rotors, blade and casing. In this study, the correlation of microstructural evolution and mechanical properties was investigated fur the specimens heat-treated at 600, 650 and $700^{\circ}C$ for 1000, 3000 and 5000 hrs. The microstructure of as-received specimen was tempered martensite with a high dislocation density, small sub-grains and fine secondary phase such as $M_23C_6$. Aging for long-time at high temperature caused the growth of martensite lath and the decrease of dislocation density resulting in the decrease in strength. However, the evolution of secondary phases had influence on hardness, yield strength and impact property. In the group A specimen aged at $600^{\circ}C\;and\;650^{\circ}C$, Laves phase was observed. The Laves phase caused the increase of the hardness and the decrease of the impact property. In addition, the abrupt growth of secondary phases caused decrease of the impact property in both A and B group specimens.

• 유통과학연구
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• 제18권4호
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• pp.13-26
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• 2020

Purpose: In this study, we will explore how the attributes of the airline's advertising model affect the corporate image and brand loyalty and the medium effect of the corporate image. Research design, data and methodology: Data collection for empirical analysis of this study was conducted online for about seven months from Jan. 2 to July 12, 2019, and was confirmed as part 292 of the final effective sample and used for demonstration analysis. Results: The property of the advertising model shown to have a significant impact in corporate image and brand loyalty. The property of the advertising, reliability and professionalism shown to have an impact in the social responsibility, but attractiveness is its responsibility and brand loyalty. Corporate images have been shown to play a meaningful role in the impact of advertising models on brand loyalty. Conclusions: The attributes of the airline's advertising model are divided into four categories, and reliability has the most influence on the image of a company and the formation of brand loyalty. The impact of the attributes of the advertising model on the relationship between corporate image and brand loyalty was investigated through an empirical analysis, and several implications were derived.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제25회 추계학술대회논문집
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• pp.173-176
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• 2005

본 연구는 지금까지 수행되어진 폭발볼트 몸체에 대한 검사방법의 신뢰성을 향상시키고 또한 각각의 검사에서 얻어진 기계적 물성수치의 비교 분석을 가능하게 함으로써 검사할 때 발생될 수 있는 착오 및 일반적인 방법만으로는 검사할 수 없는 부분들의 검사 방법을 확보하는데 있다. 볼트 몸체 검사를 위한 충격시험에 대한 충격치 기준을 마련하였으며 경도와 충격치와의 상관관계를 확인함으로써 검사항목간의 상호 확인이 가능하게 되었고, 폭발볼트 소재물성의 신뢰성을 향상시킬 수 있는 방법이 될 수 있을 것으로 판단된다.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4341-4346
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• 2011

Impact sensitivity, one of the most important screening factors for novel high energy density materials (HEDMs), was predicted by use of quantitative structure-property relationship (QSPR) based on the electrostatic potential (ESP) values calculated on the van der Waals molecular surface (MSEP). Among various 3D descriptors derived from MSEP, we utilized total and positive variance of MSEP, and devised a new QSPR equation by combining three other parameters. We employed 37 HEDMs bearing a benzene scaffold and nitro substituents, which were also utilized by Rice and Hare. All the molecular structures were optimized at the B3LYP/6-31G(d) level of theory and confirmed as minima by the frequency calculations. Our new QSPR equation provided a good result to predict the impact sensitivities of the molecules in the training set including zwitterionic molecules.

• 한국세라믹학회지
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• 제43권10호
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• pp.660-665
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• 2006

The mechanical properties of $Al_2O_3$-SiC composites manufactured with adding various amount and size of SiC particles have been measured and analyzed. Generally, the elastic modulus of the composites shows about 50% less than that of PL-8 (45 wt% $Al_2O_3$-51 wt% $SiO_2$-4 wt% other oxides), but the flexural strength is similar with each other. The impact resistance property of $Al_2O_3$-SiC composite against high velocity copper jet was lower than that of PL-8 when SiC particles of approximately 3 $\mu$m diameter was added to. It is caused probably due to the micro-pores made by oxidation of SiC particles. However, in the case of the less-weighted $Al_2O_3$-SiC composite adding to 10 wt% SiC with average diameter of 10 $\mu$m and sintering at 1200$^{\circ}C$, the impact resistance property was improved up to 37 percent compared with that of PL-8.

• 대한기계학회논문집A
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• 제20권12호
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• pp.3847-3855
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• 1996

In order to study the relationship between static and cynamic behaviors of silion caride, both quasi-static indentaiton and impact experiments of spherical particle have been conducted. The difference inmaterial behavior when using the two mehtods suggests a loading rate difference in the damate pattrern and fracture strength of silicon carbide. This investigation showed some difference in damage pattern according to particla property, especially inthe case of particle impact. There was no differences in deformation behaviors according to the loading rate when the crater profiles were compared with each other at the same contact radius. From the result of residual strength evaluation, it was found that the strength degradation began at the initiation of ring crack and its behavior was colsely related to morphologies of the damage developed which was also dependent upon the extent of deformation atthe loaidng point. In the case of static indentation, there didnot exist the particle property effects onthe strength degradation behavior.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 춘계학술발표대회 개요집
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• pp.85-85
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• 2002

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.138-140
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• 2004

In case of applying offshore standard of some class societies, the required impact test temperature is lower than that of class rule to be applied for general commercial ship. This study is performed to consider whether the impact value to be required at offshore standard of BV can be obtained or not under SAW method, 1 run both side welding, to be mainly used for butt joint of plates at domestic ship builder.