• Title/Summary/Keyword: Ahn Jae-Hong

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Rheological perspectives of industrial coating process

  • Kim, Sun-Hyung;Kim, Jae-Hong;Ahn, Kyung-Hyun;Lee, Seung-Jong
    • Korea-Australia Rheology Journal
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    • v.21 no.2
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    • pp.83-89
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    • 2009
  • Coating process plays an important role in information technology such as display, battery, chip manufacturing and so on. However, due to complexity of coating material and fast deformation of the coating flow, the process is hard to control and it is difficult to maintain the desired quality of the products. Moreover, it is hard to measure the coating process because of severe processing conditions such as high drying temperature, high deformation coating flow, and sensitivity to the processing variables etc. In this article, the coating process is to be re-illuminated from the rheological perspectives. The practical approach to analyze and quantify the coating process is discussed with respect to coating materials, coating flow and drying process. The ideas on the rheology control of coating materials, pressure and wet thickness control in patch coating process, and stress measurement during drying process will be discussed.

Optimal prestress of Tensegrity Structures for External Load (텐세그러티 구조의 외력에 대한 적정 프리스트레스 결정)

  • Ahn, Jung-Tae;Lee, Jae-Hong
    • Journal of Korean Association for Spatial Structures
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    • v.13 no.1
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    • pp.59-67
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    • 2013
  • This paper presents a new numerical method to analyse tensegrity structures by using singular value decomposition and force method. The tensegrity system consisting of compressive and tensle elements are pin-jointed system. Tensegrity structures, unlike the general structure should be preceded by form-finding. Tensegrity structures form-finding of the self-equilibrium stress stability, seeking to have the process. In this study, tensegrity structures when subjected to external loads, find the optimal pre-stress values was studied.

Characterization of Combustion Oscillation and Reduction of Abnormal Oscillation in a Power Generation Gas Turbine (발전용 가스터빈에서 발생하는 연소진동 특성 및 이상연소진동의 저감)

  • Seo, Seok-Bin;Ahn, Dal-Hong;Chung, Jae-Hwa
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1682-1685
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    • 2004
  • Gas Turbine combustors for power plant can be reduced NOx emissions using lean premixed combustion technology. But the combustors are likely to occur combustion oscillations which damage operation reliability and mechanical life of the gas turbines. In this paper, characterizations of oscillation in a gas turbine combustor for power plant are presented. Combustion dynamics occur $1{\sim}1.5$ psi in amplitude with low frequency less than 140Hz during normal operation. An abnormal high level dynamics, 2.0 psi amplitude occur at 125 Hz frequency. Abnormal combustion oscillation is reduced by modulation of fuel supply valve control schedule.

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Optimum Manufacturing Condition of Side Wall End Milling Using Response Surface Methodology (측벽 엔드밀 가공 시 반응표면법을 이용한 최적가공조건)

  • Choi, Jae-Gi;Park, Jin-Woo;Hong, Do-Kwan;Woo, Byung-Chul;Ahn, Chan-Woo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1313-1317
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    • 2007
  • Manufacturing condition is one of the most important factors in precision manufacturing. In this study, we optimized minimizing the Z vibration acceleration using RSM(response surface methodology) by table of orthogonal array. RSM was well adapted to make the analytical model of the minimum vibration acceleration and enable the objective function to be easily created and a great deal of the time in computation to be saved. Therefore, it is expected that the proposed optimization procedure using RSM can be easily utilized to solve the optimization problem of manufacture condition.

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Optimization of District Heating Pipes Considering Thermal Fatigue Life (열피로 수명을 고려한 지역난방 배관의 최적화)

  • Ahn Min-Yong;Chang Yoon-Suk;Choi Jae-Boong;Kim Sang-Ho;Kim Youn-Hong;Kim Young-Jin
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.6 s.183
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    • pp.143-150
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    • 2006
  • Recently, in proportion to increased demand on environmentally-friendly heat source, efficient management of district heating(DH) system becomes one of important issue. The objectives of this paper are to systematize data processing of transition temperature, investigate the effect of temperature variations on thermal fatigue and find out a way to improve design fractures of Korean DH pipes. For this purpose, reliable fatigue lift evaluation procedures are examined and applied to quantify thermal fatigue lives. Also, as a prototypal optimization analysis results, mean value of original cross sectional area of selected pipes was reduced 18.6% sustaining their sufficient margins against fatigue failure. So, it is anticipated that the output of this research can be used as useful information of optimal design and operation in the future.

DEVELOPMENT OF CONVENIENT ANALYTICAL METHOD OF 4-TERT-OCTYLPHENOL

  • Cho, Jae-Min;Ahn, Mee-Ryung;Kwak, Son-Hyok;Kang, Mi-Kyung;An, Eun-Ju;Kim, Jung-Mi;Choi, Sun-Ok;Choi, Hong-Seok;Chung, Hye-Joo;Yang, Ji-Sun;Lee, Yong-Bok;An, Kwang-Seuk;Yoo, Tae-Moo;Sohn, Soo-Jung
    • Proceedings of the Korea Environmental Mutagen Society Conference
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    • 2002.11a
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    • pp.163-163
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    • 2002
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