• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1198-1201
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• 2006

ISO 140-1 recommends installing diffusing elements in the room if there are large variations of the sound pressure level caused by strong standing wave. Also it requires that reverberation time should not be long or short. In accordance to this regulation, we adjusted the reverberation time in the range of $1{\sim}2$ sec by using 4 types of diffusing elements. This paper demonstrates how to balance the reverberation time in the range of $1{\sim}2$ sec by using several types of diffusing elements.

• 대한기계학회논문집A
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• 제30권10호
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• pp.1284-1292
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• 2006

Heat treatment is a controlled heating and cooling process to improve the physical and/or mechanical properties of metal products without changing their shapes. Today finite element method is widely used to simulate lots of manufacturing processes including heat treatment and surface hardening processes, which aims to reduce the number of time- and cost-consuming experimental tryouts. In this study we tried, using this method, to simulate the full carburizing process that consists of carburizing, diffusing and quenching, and to predict the distribution of carbon contents, phase fraction and hardness, thermal deformation and other mechanical characteristics as the results. In the finite element analysis deformation, heat transfer, phase transformation and diffusion effects are taken into consideration. The carburizing process of a lock gear, a part of the car seat recliner, that is manufactured by the fine blanking process is adopted as the analysis model. The numerical results are discussed and partly compared with experimental data. And a combination of process parameters that is expected to give the highest surface hardness is proposed on the basis of this discussion.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.189-189
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• 2016

In this study, the Al-rich AlTiSiN thin films that consisted of TiN/AlSiN nano-multilayers were deposited on the steel substrate by magnetron sputtering, and their high-temperature oxidation behavior was investigated, which has not yet been adequately studied to date. Since the oxidation behavior of the films depends sensitively on the deposition method and deposition parameters which affect their crystallinity, composition, stoichiometry, thickness, surface roughness, grain size and orientation, the oxidation studies under various conditions are imperative. AlTiSiN nano-multilayer thin films were deposited on a tool steel substrate, and their oxidation behavior of was investigated between 600 and $1000^{\circ}C$ in air. Since the amount of Al which had a high affinity for oxygen was the largest in the film, an ${\alpha}-Al_2O_3-rich$ scale formed, which provided good oxidation resistance. The outer surface scale consisted of ${\alpha}-Al_2O_3$ incoporated with a small amount of Ti, Si, and Fe. Below this outer surface scale, a thin ($Al_2O_3$, $TiO_2$, $SiO_2$)-intermixed scale formed by the inwardly diffusing oxygen. The film oxidized slower than the $TiO_2-forming$ kinetics and TiN films, but faster than ${\alpha}-Al_2O_3-forming$ kinetics. During oxidation, oxygen from the atmosphere diffused inwardly toward the reaction front, whereas nitrogen and the substrate element of iron diffused outwardly to a certain extent.

• 한국세라믹학회지
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• 제35권1호
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• pp.55-65
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• 1998

Ag-36.8a%Cu-7.4at%Ti 조성의 브레이징 합금을 Si3N4 기판위에 브레이징한 후 브레이징 합금의 산화거동을 대기중 400, 500, 600$^{\circ}C$에서 조사하였다. 브레이징 합금의 구성원소인 Ag는 산화되지 않고 Cu와 Ti가 산화되며, 산화거동은 포물선적 산화법칙을 따랐다. 브레이징 합금의 산화에 따른 활성화에너지는 80kj/ mol 으로서 소량 첨가된 활성원소인 Ti에 의하여 순수한 Cu의 산화시 활성화에너지보다 감소하였다. 산화 초기에 생성되는 외부산화물은 Cu이온의 외부확산에 의해 성장이 지배되는 Cu산화물로 구성되어 있었다. 산화기간이 경과함에 따라 외부산화물층 아래에서 Cu의 농도는 감소되고 Ag의 농도는 증가하는 농도구배가 발생하여, 브레이징 합금의 산화물은 Cu산화물층(CuO)/Ag잉여층/Cu산화물층(Cu2O)/Ag잉여층의 다층구조를 갖았다. 또한, 분위기중의 산소는 Cu산화물 및 Ag잉여층을 통해 브레이징 합금 내부로 확산되어 브레이징 합금내의 Ti와 반응하여 내부산화물 TiO2를 생성하였다.

• 유통과학연구
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• 제14권4호
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• pp.67-79
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• 2016

Purpose - Over recent years, we have concerned about safety and quality on food products because of delivery complexity. The dependence of foreign food products escalate supply of products. And there are often negligent accident of marine and agricultural products. Therefore, the complexity increases the importance of safety on food and information quality for consumers. In spite of the interest augmentation of various interested parties, there is decrease in reliability and effectiveness, if it would be established without the right directivity. For the study, we tried to examine the first considerations the point of - view in service environment and information quality with accepting and diffusing the Traceability System. Then, we tried to verify the relationships between the factors of TS and the determinants of behavior decision. Next, we made efforts to find the mutual relationship among distributors, producers, consumers and the other prerequisite factors from the point of view in service environment and information quality in order to operate effectively the information perspective and system. Research design, data, and methodology - For the purpose of this study, the samples of consumers were targeted to Traceability System, and 661 people have been investigated. Through theoretical discussion of previous research, nine hypotheses were established, the influence of Continuous User Intention in TS. In order to test the hypotheses, a survey had conducted for 661 consumers as opinion leaders in their 20s-60s as data, and structural equation modeling was used. The difference analysis between Agricultural and Marine Products in TS; SPSS 22.0 and AMOS 22.0 were used for statistical analysis. Results - The major findings from this study were as follow; all factors of information quality excluding completeness and a social-impact had effects on the ease of use; all factors excluding understand ability in information quality and a social-impact had effects on the usefulness; completeness and social-impact had effects on perceived value; the ease of use had effects on usefulness and perceived value; usefulness had effects on perceived value and the intention of continuous use. From the results of different analysis, the CPLT(Completeness) factor has positive effects on Easy of USE and PV(Perceived Value) strongly in agricultural products. On the other hand, Social Duty has positive effects on Easy of Use strongly in marine products. Conclusion - In the age of information overflowing, TS will be a burden for users if it places too much emphasis upon accessibility. To accept and diffuse TS safely, therefore, Information System should be settled first into initial market formation. In addition, if TS elements are considered in conjunction with information factors and user environment, the acceptance and diffusion of TS would make synergy effect, even better. That is, this study contributes to the acceptance and diffusion of Traceability System. Accordingly, information quality will be settled into initial market formation. Also, social-impact element will be considered in conjunction with information quality's factors, and it will make synergy effect.