• 대한금속재료학회지
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• 제49권11호
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• pp.823-830
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• 2011

Structural change in an amorphous alloy was measured by applying a load below the global yield stregth at ambient temperatures. It was observed that the magnitude of the apparent structural change occuring in the amorphous alloy is determined by the compatative relationship between the stress-induced disordering process and the thermally-activated relaxation process. Structural disorder was observed to take place even at a stress well below the global yield, and the degree of the disorder was increased abruptly at the earlier stage of loading and saturated with time. In the mean time, unlike the previous belief, the relaxation process was observed to occur even at embient temperatures, and the degree of the relaxation was observed to increase linearly with time. The analytical equation predicting the structural change was proposed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.139-142
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• 2004

Nickel base superalloys are widely used for high temperature applications due to heat resisting capability and corrosion resistance at high temperatures. Superalloys with many strengthening alloying elements are frequently used in powder form to alleviate harmful effects of alloy segregation. HIP (hot isostatic pressing) and DB (diffusion bonding) as a form of solid-state bonding process is used to make turbine components, such as integrated turbine rotors. HIP/DB process requires many technical overcomes related to dimensional changes as well as microstructural control. In this research, HIP/DB process for nickel base superalloys, Udimet 720 and MM 247, were investigated with a view to control the dimensional change during the consolidation process. Simple disc-shaped cans were used to select the conceptual die design for the control of the dimensional change especially in radial direction. The change in the shape of consolidated shape was investigated using commercial FE code with constitutive equations fur low temperature plasticity deformation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.171-174
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• 2004

Superalloys with many strengthening alloying elements are frequently used in powder form to alleviate harmful effects of alloy segregation. HIP (hot isostatic pressing) and DB (diffusion bonding) as a form of solid-state bonding process is often used to make turbine components, such as integrated turbine rotors. HIP/DB process requires many technical overcomes related to dimensional changes as well as microstructural control. In this research, HIP/DB process for nickel base superalloys, Udimet 720, were investigated with a view to control the dimensional change during the consolidation process. Simple disc-shaped cans were used to select the conceptual die design for the control of the dimensional change especially in radial direction. The change in the shape of consolidated shape was investigated using commercial FE code with constitutive equations for low temperature plasticity and creep deformation.

• 지역사회간호학회지
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• 제23권3호
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• pp.316-326
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• 2012

Purpose: This study was to identify the factors associated with stages of exercise behavior change of residents in a community on the basis of the Transtheoretical Model. Methods: Data were collected from 520 residents of a community using a self-report questionnaire. The survey variables comprised the stages of exercise behavior change, the process of change, decisional balance and self efficacy. Results: There were significant differences in the process of change, decisional balance and self efficacy by the stages of exercise behavior change. The factors associated with transition from pre-contemplation to contemplation were consciousness raising and self efficacy; regarding those from contemplation to preparation, cons of the decisional balance and social liberation; regarding those from preparation to action, dramatic relief and counter conditioning; regarding that from action to maintenance, cons of the decisional balance. Conclusion: TTM would be applicable to explain the exercise behavior of some residents in a community, which suggested that the programs for improving exercise behavior of residents in a community need to be developed.

• International Journal of Precision Engineering and Manufacturing
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• 제7권3호
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• pp.56-59
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• 2006

UV laser micromachining is generally used to create microstructures for micro-products through a sequence of lithography-based photo-patterning steps. However, the micromachining process is not suitable for rapid realization of complex 3D micro-products because it depends on worker experience. In addition, the cost and time required to make many masks are excessive. In this paper, a more effective and rapid micro-manufacturing process, which was developed based on laser micromachining, is proposed for fabricating micro-products directly using UV laser ablation and phase-change filling. The filling process is useful for holding the micro-products during the ablation step. The proposed rapid micro-manufacturing process was demonstrated experimentally by fabricating 3D micro-products from functional UV-sensitive polymers using 3D CAD data.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.26-29
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• 2003

UV laser micromachining are generally used to create microstructures for micro product through a sequence of lithography-based photopatterning steps. However, the micromachining process is not suitable for the rapid realization of complex microscale 3D product because it depends on worker experiences, excessive cost and time to make many masks. In this paper, the more effective micro rapid manufacturing process, which is developed upon the base of laser micromachining. is proposed to fabricate micro products directly using UV laser ablation and phase change filling. The filling process is useful to hold the micro product during the next ablation step. The proposed micro rapid manufacturing process is also proven experimentally that enables to fabricate the 3D microscale products of UV sensitive polymer from 3D CAD data to functional micro parts.

• 한국정밀공학회지
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• 제22권11호
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• pp.196-201
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• 2005

UV laser micromachining are generally used to create microstructures for micro product through a sequence of lithography-based photopatterning steps. However, the micromachining process is not suitable for the rapid realization of complex 3D micro product because it depends on worker experiences, excessive cost and time to make many masks. In this paper, the more effective micro rapid manufacturing process, which is developed upon the base of laser micromachining, is proposed to fabricate micro products directly using UV laser ablation and phase change filling. The filling process is useful to hold the micro product during the next ablation step. The proposed micro rapid manufacturing process is also proven experimentally that enables to fabricate the 3D micro products of UV sensitive polymer from 3D CAD data to functional micro parts.

• 인터넷정보학회논문지
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• 제5권4호
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• pp.11-22
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• 2004

프로젝트를 수행함에 있어서 프로세스의 지속적인 개선 및 개선된 프로세스, 생산되는 산출물, 태스크들의 변경을 모든 사용자에게 통지하고 관리하는 작업은 필수적이다. 기존의 프로젝트 관리 도구는 프로젝트 활동의 정의 및 변경을 지원하고, 형상관리 도구는 버전제어, 작업공간 관리, 빌드 관리 등을 지원한다. 프로세스와 산출물을 관리하기 위해서 서로 다른 두개의 도구를 사용하는 것은 각각의 도구를 구매하는데 많은 비용이 들 뿐만 아니라 다양한 도구의 사용법을 익혀야 하는 번거로움이 있다. 따라서 된 논문에서는 웹을 기반으로 프로세스 및 산출물 관리 기능 통합, 인터페이스 통합, 자료 통합 도구의 모델을 제안하였다. 제안한 도구는 ebXML을 이용하여 컴포넌트 기반 개발 프로세스 모델을 정의하고. 프로세스의 진행 상태 기록, 변경 요청에 따른 처리, 태스크별 작업 진행 보고서 작성, 산출물 등록과 변경, 버전 기록, 산출물 또는 서식 검색 등의 기능을 수행하도록 하였다. 또한 제안한 통합관리 도구를 사용함으로써 소프트웨어 공학 활동에 참여하는 시스템 관련 자들이 분산 개발 환경에서 프로세스 수행에 필요한 정보와 산출물 관리에 요구되는 정보를 공유하여 관리의 체계화 및 표준화를 얻도록 하였다.

• 한국가시화정보학회지
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• 제21권2호
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• pp.63-71
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• 2023

Energy storage and distribution technologies are emerging as important factors as research on renewable energy continues. Analyzing the thermal flow of phase change material inside a latent heat storage device and to predict the phase change time is an important part for improvement of thermal performance. However, most of the current research is based on the trial-and-error experimental investigation to measure the phase change time. Therefore, in this study, a can-type phase change material container was designed, and the numerical method for analyzing the thermal flow of phase change material was established and validated. The error rate of the phase change time between the numerical and experimental results was within 5%, which proves its reliability. As a result, the phase change finishing times were found to be 78 minutes with inlet fluid temperature of 80℃ during charging process, and 126 minutes with inlet fluid temperature of 9℃ during discharging process.

• 대한산업공학회지
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• 제20권4호
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• pp.113-134
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• 1994

A radial basis hybrid neural network (RHNN) is presented for an on-line detection of machine condition change. Two-phase modeling by RHNN is designed for describing a machine condition process and for predicting future signal. A moving block procedure is also designed for detecting a process change. A fast on-line learning algorithm, the recursive least square estimation, is introduced. Experimental results showed the RHNN could be utilized efficiently for on-line machine condition monitoring.