• Title/Summary/Keyword: 오일-에어

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계단형 낙차공의 수리모형 실험 및 수치모의 세굴 형상 비교 분석

  • Lee, Ji-Hun;Jo, Hun-Sik;Yeo, Chang-Geon;Lee, Seung-Oh
    • Proceedings of the Korea Water Resources Association Conference
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    • 2011.05a
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    • pp.142-142
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    • 2011
  • 자연형 하천 복원 사업은 하천 복원 사업과 함께 친환경적 기능을 중시하는 연구가 활발하게 진행중이다. 본 연구에서는 계단형 낙차공의 평면형상의 곡선형 낙차공에서의 수리모형 실험과 수치모의를 통해 흐름 특성 및 형상을 검증하였다. 계단형 낙차공으로 수리모형 실험과 수치모의를 한 결과 복잡한 수공 구조물의 흐름 특성은 동일하게 나타났다. 본 연구에서 수리모형과 수치모형은 동일한 SCALE과 실험조건으로 하였다. 계단형 낙차공은 우측에어도가 설치되어 있어 흐름이 우측으로 많이 편향 되어 세굴심이 일어나는 것을 확인 할수 있다. 이러한 세굴 특성은 실제 자연형 하천에 적용 되었을 경우 문제점을 야기 시킬 수 있으므로 본 연구 결과를 분석하여 물받이공 산정 등에 활용될 수 있을 것이다.

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A Stud on the Water Vapor Permeability of Air Cell Structure of Ultra Rapid Harding Membrane Waterproofing Using Fixed Screw Hybrid Method (고정형 스크류 혼합 방식을 이용한 초속경 도막방수층 에어 셀 구조의 수증기투과성에 관한 연구)

  • Kim, Yun-Ho;Kim, Hyun-Min;Park, Jin-Sang;Song, Je-Young;Oh, Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.05a
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    • pp.225-226
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    • 2013
  • Existing polyurethane membrane waterproofing has been raised defects such as heaving. Therefore, We will be utilizing as the basic experimental data by the water vapor permeability test to the air cell structure of ultra rapid harding membrane waterproofing using the static mixing system in this study.

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Numerical Study on the Effects of Air Decking in Half Charge Blasting Using AUTODYN (AUTODYN을 이용한 하프장전 발파공법의 에어데크 효과에 대한 수치해석적 연구)

  • Baluch, Khaqan;Kim, Jung-Kyu;Kim, Seung-Jun;Jin, Guochen;Jung, Seung-Won;Yang, Hyung-Sik;Kim, Nam-Soo;Kim, Jong-Gwan
    • Explosives and Blasting
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    • v.36 no.4
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    • pp.1-8
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    • 2018
  • This numerical study was intended to evaluate the applicability of the half charge blasting to mining and tunnelling. The half charge blasting is a method that two separate rounds are sequentially blasted for the rock burdens in which long blast holes have already been drilled at one operation. The aim of the method is to decrease the construction cost and period in mining and tunnelling projects as well as to increase the blasting efficiency. Several numerical analyses were conducted by using the Euler-Lagrange solver on ANSYS AUTODYN to identify the effects of the suggested method on the blasting results in underground excavations. The overall performance of the suggested method was also compared to an ordinary blasting method. The analysis model was comprised of the Eulerian parts (explosive, air, and stemming materials) and the Lagrangian parts (rock material). As a result, it was found that, owing to the air decks formed in the bottom parts of the long blast holes, the first round of the suggested method presented a higher shock pressure and particle velocities in the vicinity of the blast holes compared to the ordinary blasting method.

The narrative space of sound design in films (영화 사운드디자인의 내러티브 공간 연구)

  • Lee, Dong-Hwan
    • Journal of Digital Contents Society
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    • v.17 no.5
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    • pp.391-400
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    • 2016
  • The purpose of this study is to reassert the important role of sound design in creating narrative space in films. The main focus is on re-interpreting Chion's sound space composition as a narrative structure. The sound design process has been analyzed to find that the physical properties of sound are purposely manipulated to create the layers of sound to be perceived by the audience in the same way as human perception and cognition of the actual reality work, eventually to create the cinematic reality. The hierarchy of the layers is determined by the importance of the narrative information contained in each sound, with the higher layers being appropriate to convey the information of the narrative, and the lower layers being efficient to deliver the emotion to the audience. With this idea, each of the Chion's space composition is explained as a distinctive area in telling a story with the separate narrative role from the others.

Thermal Characteristic Analysis of a High-Speed Horizontal Machining Center with Built-in Motor and Linear Motors (내장형 모터와 리니어 모터를 적용한 초고속 수평형 머시닝센터의 열 특성 해석)

  • 김석일;조재완
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.416-423
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    • 2004
  • This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/fin. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

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Reactor design of PECVD system using a liquid aerosol feed method (미립액상법을 위한 PECVD 반응로설계)

  • 정용선;오근호
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.7 no.2
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    • pp.235-243
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    • 1997
  • The high-$T_c$ superconducting phase, $YBa_2Cu_3O_x$, was deposited on the single crystal MgO substrate, using a liquid aerosol feed method in a plasma enhanced chemical vapor deposition(PECVD) reactor. The effect of the plasma distribution depending on the design of a reactor was studied by the analysis of the microstructures of thin films. The particles landed were frequently observed on the films and the two causes that were responsible for the particle deposition were explained. The particles were deposited by the unstable and non-uniform plasma and the low evaporation rate of the precursors. Also, the thin film deposition rate decreased significantly as the distance between the evaporating location and the substrate increased.

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An Analysis of Engine Failures Using Multivariate Data Analysis Method (다변량해석법을 이용한 기관고장분석)

  • 윤석훈
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.23 no.4
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    • pp.198-203
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    • 1987
  • The basis of all approaches to improve reliability of marine engines exists in analyzing the field data of troubles and failures on marine engines. This paper analyses the data of troubles and failures on marine engines by Principal Component Analysis Method, one of Multivariate Data Analysis Method. The total number of data investigated is 211 and the observation period is 9 years. The analyzed factors are categorized among five groups respectively; electric.automatic control equipments, auxiliary machinery, pipings, refrigerators.air conditioners, and main engine. The failures in main engine are discovered by a definite fact of disorder, on the contrary, the failures in auxiliary machinery, refrigerators and air conditioners are discovered by sensible judgement of the operators.

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Air Cooling Characteristics of a High Speed Spindle System for Machine Tools (공작기계용 고속주축계의 공기냉각특성에 관한 연구)

  • Choi, Dae-Bong;Kim, Suk-Il;Song, Ji-Bok
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.1
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    • pp.123-128
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    • 1994
  • A high speed spindle system for machine tools can be used to reduce the machining time, to improve the machining accuracy, to perform the machining of light metals and hard materials, and to unite the cutting and grinding processes. In this study, a high speed spindle system is developed by applying the oil-air lubrication method, angular contact ball bearings, injection nozzles with dual orifices, cooling jacket and so on. And an air cooling experiment for evaluating the performance of the spindle system is carried out. Especially, in ofder to establish the air cooling conditions related to the development of a high speed spindle system, the effects of cooling air pressure, oil supply rate, air supply rate and rotational spindle speed are studied and discussed on the bearing temperature rise and frictional torque. Also the effects of cooling air pressure, rotational spindle speed and spindle system structure is investigated on the bearing temperature distribution. The experiment on the test model reveals the usefulness of the air cooling method.

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Kriging of Daily PM10 Concentration from the Air Korea Stations Nationwide and the Accuracy Assessment (베리오그램 최적화 기반의 정규크리깅을 이용한 전국 에어코리아 PM10 자료의 일평균 격자지도화 및 내삽정확도 검증)

  • Jeong, Yemin;Cho, Subin;Youn, Youjeong;Kim, Seoyeon;Kim, Geunah;Kang, Jonggu;Lee, Dalgeun;Chung, Euk;Lee, Yangwon
    • Korean Journal of Remote Sensing
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    • v.37 no.3
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    • pp.379-394
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    • 2021
  • Air pollution data in South Korea is provided on a real-time basis by Air Korea stations since 2005. Previous studies have shown the feasibility of gridding air pollution data, but they were confined to a few cities. This paper examines the creation of nationwide gridded maps for PM10 concentration using 333 Air Korea stations with variogram optimization and ordinary kriging. The accuracy of the spatial interpolation was evaluated by various sampling schemes to avoid a too dense or too sparse distribution of the validation points. Using the 114,745 matchups, a four-round blind test was conducted by extracting random validation points for every 365 days in 2019. The overall accuracy was stably high with the MAE of 5.697 ㎍/m3 and the CC of 0.947. Approximately 1,500 cases for high PM10 concentration also showed a result with the MAE of about 12 ㎍/m3 and the CC over 0.87, which means that the proposed method was effective and applicable to various situations. The gridded maps for daily PM10 concentration at the resolution of 0.05° also showed a reasonable spatial distribution, which can be used as an input variable for a gridded prediction of tomorrow's PM10 concentration.

Female Development in Nineteenth-Century England and Dynamics of the Bildungsroman (19세기 영국 여성의 "성장"과 성장소설의 역동성)

  • Oh, Jung-Hwa
    • Women's Studies Review
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    • v.29 no.2
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    • pp.3-35
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    • 2012
  • This paper attempts to examine complicated relations which the nineteenth-century English novel of female development has with the Bildungsroman genre, and to discuss that the story of female development effectively realizes the potential dynamics of the genre. It looks into the history of discussions on the Bildungsroman which began at the end of the nineteenth-century in Germany and developed among twentieth-century Anglo-American critics, and those on the female development which didn't start until feminist criticism ventured out at the end of 1970s, and have developed into various perspectives ever since in accordance to the progress of feminist criticism. In general, Bildungsroman criticism considers that it portrays the process how the protagonist develops self and achieves an accommodation with society. However, this paper points out that the Bildungsroman is the narrative form which represents conflicts between self and society caused by idealizing the infinitive possibility of self-determination while simultaneously presenting the limited goal of social integration. It argues that the subversive dynamics of the genre can give full play to its potential when it reveals contradictions and tensions between individual subjectivity and integration into society and connects them with criticism of political and social structures. It is the stories of female Bildungshelds depicted by nineteenth-century female writers that exquisitely embody the subversive potential of the Bildungsroman. They acutely experience alienation from society where independency or autonomy is fundamentally impossible because the ideology of separate spheres does not allow them to live a meaningful life economically and sociologically outside the marriage. An example of a female Bildungsheld whose conflicts between development of self and integration with society are doubled by gender is Jane Eyre. Jane Eyre is a representative Bildungsroman with subversive dynamics, which tells the story of female development but splits itself through various techniques inserting contradictory and opposite meanings, thus resignifying female development and questioning social and political structures.