• Title/Summary/Keyword: 정구창

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An Implicit Unstructured Finite Element Method for Diffraction of Water Waves by Two-Dimensional Floating Breakwaters (부유체 주위의 2차원 회절 문제를 위한 내율적 비정렬 격자 유한요소해법)

  • 정구창
    • Journal of Ocean Engineering and Technology
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    • v.11 no.4
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    • pp.90-101
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    • 1997
  • A hybrid element method is presented for two-dimensional diffraction problem of water waves. In this method, only a limited fluid domain close to irregular bodies is discretized into conventional finite elements, while the remaining infinite domain is treated as one element with analytical representations of high accuracy. A finite element grid is automatically generated by using Dealunay triangulation based on the Bowyer's algorithm and a linear system of equations is approximately solved with the ILU-CGS algorithm. To validate the present scheme, Computational results are compared with the existing experimental data and other numerical solutions.

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A study on the ideological foundation of Park jin-young[朴震英] - Mainly studied the relationship of Jung gu[鄭逑] - (광서(匡西) 박진영(朴震英)의 사상적 토대 고찰 - 한강(寒岡) 정구(鄭逑)를 위시한 사승(師承) 관계를 중심으로 -)

  • Kim, hyung-tae
    • (The)Study of the Eastern Classic
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    • no.54
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    • pp.235-252
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    • 2014
  • This paper is examining the ideological underpinnings of Park Jin-young[朴震英]. He was intellectual activity is based on Haman[咸安] Gyeongsang-namdo[慶尙南道]. And He was causing the Righteous Army[義兵] saved the country from the crisis of Imjin War[壬辰倭亂, 1592~1598] and the Byongja War[丙子胡亂, 1636~1637] in Mid-Joseon[朝鮮] Dynasty. Therefore, he had to practice patriotism and love people. The purpose of this paper is centered on the acts of Park Jin-young to focus on its ideological foundation to be sure. A cause[大義名分] was laying on the side and the real meaning of the terms of participation and his a far-sighted view [達觀] ever conduct of life[處世] divided into such discussions were developed. In addition, the formation of his ideas around the Jung gu[鄭逑] influenced correlating it with the teacher and student relationships were investigated. Park Jin-young is Im-Byeong War[壬丙兩難] since emerged on the Joseon [朝鮮] Social Jon-ju[尊周] thought was one of the representative figures. His mentor Jung gu was the cause, seriously. And he cause, the influence of the teacher very seriously here was typical of that era. The people loved teacher. And his disciples to overcome difficulties that influence the Righteous Army sought to raise the country. His teachers have taught him Confucian influence. And behave appropriately when life. Park Jin-young acted appropriately when affected by such a life. Consequently, he was a true intellectual in those times.

Surface damage analysis of Head/Disk interface using AFM (AFM을 이용한 Head/Disk의 표면파손에 관한 고찰)

  • 정구현;이성창;김대은
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.357-361
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    • 1997
  • In this work surface damage of head and disk of head disk drive was analysed using an Atomic Force Microscpoe. The initial damage of the disk occurred by generation of extermely small wear particles. Also it was show that wear particles tend to pile up near the front side of the slider. The surface damage mechanism of drag test and contact-start-stop test was found to be quite similar.

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A Study on the Surface Damage between Head/Disk Interfaces by Using AFM (AFM을 이용한 Head/Disk의 표면 파손에 관한 고찰)

  • 이성창;정구현;김대은
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.9
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    • pp.167-174
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    • 1998
  • In this work the surface damage of head and disk of a hard disk drive was analysed using an Atomic Force Microscope. The initial damage of the disk occurred by generation of extremely small wear particles. Also it was shown that wear particles tend to pile up near the front side of the slider. The surface damage mechanism of drag test and contact-start-stop test was found to be quite similar.

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Investigation of ultraprecision machining characteristics by molecular statics simulation method (분자정역학 기법을 이용한 초미세 절삭특성에 관한 고찰)

  • 정구현;이성창;김대은
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.3
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    • pp.122-129
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    • 1997
  • Machining technology has emerged to the point of performing atomic-scale fabrication. In tail paper atomic-scale machining characteristics are investigated by using Molecular Statics simulation method. The cutting model used in this work simulates machining with tools such as an AFM. It is shown that built-up edge formation and cutting forces depend on tool tip geometry. Also, the material flow during cutting is shown for various cutting conditions such as depth of cut, rake angle, and edge radius of tool.

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Characteristics of friction and stiction in head/disk interface (헤드/디스크 시스템의 마찰력 측정 및 stiction 특성)

  • 이성창;정구현;김대은
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1997.10a
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    • pp.45-50
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    • 1997
  • In recent years the recording density of hard disk has been increasing largely due to the decreasing flying height of head. However, as the flying height is decreased the reliability issue becomes ever more critical. This is because the reliability and durability of hard disk is related to the head/disk interaction as the two components come into partial or full contact. In this work characteristics of friction and stiction in head/disk interface was investigated using constant speed drag test and CSS(contact-start-stop) test. The purpose of this research is to identify the frictional properties of head/disk interface

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Application Evaluation of Best Management Practices for Agricultural Non-Point Source Pollution using Delphi Survey Method (전문가 델파이 방법을 이용한 농업 비점오염 저감 기술의 현장 적용성 조사)

  • Kim, Min-Kyeong;Jung, Goo-Bok;Kim, Min-Young;Kim, Myung-Hyun;Cho, Kwang-Jin;Choi, Soon-Kun;Hong, Seong-Chang;So, Kyu-Ho
    • Korean Journal of Environmental Agriculture
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    • v.33 no.2
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    • pp.144-147
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    • 2014
  • BACKGROUND: It is essential to prioritize the exact and clear understanding of agricultural nonpoint source pollution (NPS) controls. The realistic policies and systems should also be developed based on this understanding. Therefore, this study aimed to present agricultural Best Management Practices (BMPs) applicable for the fields based on the Delphi survey result. METHODS AND RESULTS: This study deduced the evaluation items to assess each BMP for agricultural NPS control and conducted the surveying using the Delphi method based on agricultural BMP experts. In addition, its on-the-spot application were evaluated. Considering its importance, technical, social and economic proprieties showed that political support was ranked first and followed by cost investment, labor investment, reduction effect and resident participation. The survey findings by agricultural BMP experts showed the good performance of on-the-spot application can be achieved from fertilization by soil testing, residue and green manure application and contour plowing which are applicable within a field. Agricultural BMPs, highly applicable for the fields, were the countermeasures that farmers who are the principal bodies of agricultural NPS control could be participated directly. CONCLUSION: The active participation of farmers is essential for effective control of agricultural NPS. It is necessary to establish various incentive systems.

Inactivation of Escherichia coli in Surface Water of Saturated Soil with the Pig Manure-based Liquid Fertilizers by Ultraviolet Radiation (자외선에 의한 가축분뇨 액비 시용 논 표면수 중 대장균 사멸율 변화)

  • Kim, Min-Kyeong;Jung, Goo-Bok;Hong, Seung-Chang;Kang, Seong-Soo;Kwon, Soon-Ik
    • Korean Journal of Soil Science and Fertilizer
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    • v.44 no.3
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    • pp.368-370
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    • 2011
  • Liquid manure fertilizer drived from pig slurry is a valuable source of nutrients for crop production. However, there is no study for environmental assessment regarding microbial quality to apply liquid manure fertilizer. Therefore, this study aimed at quantifying the level of environmental impact on fecal coliform (Escherichia coli or E. coli ) survival in saturated soil such as paddy field. Surface water samples were collected up to 168 and 11 hours under natural sunlight and artificial ultraviolet radiation, respectively. The inactivation rate of E. coli under natural sunlight increased gradually after 48 hours. However, the inactivation rate of E. coli under artificial ultraviolet radiation increased linearly over time. Our findings suggested that the ultraviolet radiation is the limited factor on E. coli survival in surface water of saturated soil. This result will provide useful and practical guideline to applicators of agricultural soil in deciding appropriate handling and time frames for preventing pollution of water quality for sustainable agriculture.