• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.1
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• pp.1-7
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• 2006

Linear stability analysis of 2-dimensional wall jet is conducted by using parabolized stability equation (PSE). Wall jet is found to be modelled well by boundary layer approximation except for the neighborhood of the nozzle exit, and the introduction of local similarity variable makes the streamwise basic flow Reynolds number independent. Stability characteristics of the wall jet obtained

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.204-208
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• 2000

An approximate similarity theory has been applied to predict the forming load of non-axisymmetric forging of aluminum alloys through model material tests. The approximate similarity theory is applicable when strain rate sensitivity, geometrical size, and die velocity of model materials are different from those of real materials. Actually, the forming load of yoke, which is an automobile part made of aluminum alloys(Al-6061), is predicted by using this approximate similarity theory. Firstly, upset forging tests are have been carried out to determine the flow curves of three model materials and aluminum alloy(Al-6061), and a suitable model material is selected for model material test of Al-6061. And then hot forging tests of aluminum yokes have been performed to verify the forming load predicted from the model material, which has been selected from above upset forging tests. The forming loads of aluminum yoke forging predicted by this approximate similarity theory are in good agreement with the experimental results of Al-6061 and the results of finite element analysis using DEFORM-3D.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.71-75
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• 1999

An approximate similarity theory has been applied to predict the forming load of non-axisymmetric forging of aluminum alloys through model material tests. The approximate similarity theory is applicable when strain rate sensitivity geometrical size and die velocity of model materials are different from those of real materials. Actually the forming load of yoke which is an automobile part made of aluminum alloys(Al-6061) is predicted by using this approximate similarity theory. Firstly upset forging tests are have been carried out to determine the flow curves of three model materials and aluminum alloy(Al-6061) and a suitable model material is selected for model material test of Al-6061 And then and forging tests of aluminum yokes have been performed to verify the forming load predicted from the model material which has been selected from above upset forging tests, The forming loads of aluminum yoke forging predicted by this approximate similarity theory are in good agreement with the experimental results of Al-6061 and the results of finite element analysis using DEFORM-3D.

• (The)Study of the Eastern Classic
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• no.54
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• pp.253-288
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• 2014

A pen name Chuman(秋巒; a mountain of Fall), Jeong Ji-wun(1509-1561) is a famous person wrote "Cheonmyeong-Doseol" which made two men, Yi Hwang and Ki Dae-$s{\breve{u}}ng$ dispute Sachil-Nobyeon(traditional argument about heart/mind). But except this point, few people of nowadays know who Jeong Ji-wun was. Therefore this paper is made for understanding Jeong Ji-wun in the point of view in history of thought. "Cheonmyeong-Doseol" by Jeong Ji-wun had systemized traditional theory of Cheonil-Habil(sky and human are an organic body), through this theory, Jeong Ji-wun had taken an important role who developed the Neo-Confucian theory in the field of political thought at that time. All Neo-Confucian literati used the theory of heart/mind as a sole useful method in political field from after King Myeonjong and Seonjo. "Cheonmyeong-Doseol" by Jeong Ji-wun was a first step to this scene. Especially "Cheonmyeong-Doseol" was got famous by arguments of Yi Hwang and Ki $Dae-s{\breve{u}}ng$, great scholars in the history of Chosun Dynasty. They firstly developed Sachil-Nobyeon, Sandan(pure morality) comes from li, Chiljeong(emotions) comes from Ch'i, is it right or not? This argument with "Cheonmyeong-Doseol" raised up the level of Neo-Confucian theory at that time. Like this, "Cheonmyeong-Doseol" was on the first step for Neo-Confucian literati to study and develop their theory of political thought which covered politics in Chosun Dynasty.