• 제목/요약/키워드: mass movements

검색결과 129건 처리시간 0.023초

상판 위 질량의 순간적인 움직임에 의해 가진되는 6-자유도 공압제진대의 진동 응답에 대한 연구 (A study on response analysis of 6-DOF pneumatic vibration isolation table loaded by transient movements of carriage on it)

  • 선종오;신윤호;김광준
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 춘계학술대회논문집
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    • pp.97-102
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    • 2007
  • As environmental vibration requirements on precision equipments get more stringent, use of pneumatic vibration isolators becomes more crucial and, hence, their dynamic performance needs to be further improved. Dynamic behavior of those pneumatic vibration isolation tables is very important to both manufacturer and customer as performance specifications. Together with conventional transmissibility, transient response characteristics are another critical performance index especially when movements of components, e.g., x-y tables, of the precision equipments are very dynamic. In this paper, analysis on transient response of a pneumatic vibration isolation table loaded by a mass moving on it is presented. This is a conventional dynamics problem on a rigid body with 6 degree of freedom and a mass with another degree of freedom. How to obtain transient responses of the isolation table is described when the movements of the mass are prescribed relative to the table.

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상판 위 질량의 순간적인 움직임에 의해 가진되는 6-자유도 공압제진대의 진동 응답에 대한 연구 (A Study on Response Analysis of 6-DOF Pneumatic Vibration Isolation Table Loaded by Transient Movements of Carriage on It)

  • 선종오;신윤호;김광준
    • 한국소음진동공학회논문집
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    • 제17권6호
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    • pp.515-523
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    • 2007
  • As environmental vibration requirements on precision equipments get more stringent, use of pneumatic vibration isolators becomes more crucial and, hence, their dynamic performance needs to be further improved. Dynamic behavior of those pneumatic vibration Isolation tables is very important to both manufacturer and customer as performance specifications. Together with conventional transmissibility, transient response characteristics are another critical performance index especially when movements of components, e.g., x-y tables, of the precision equipments are very dynamic. In this paper, analysis on transient response of a pneumatic vibration isolation table loaded by a mass moving on it is presented. This is a conventional dynamics problem on a rigid body with 6 degree of freedom and a mass with another degree of freedom. How to obtain transient responses of the isolation table is described when the movements of the mass are prescribed relative to the table.

동축 케이블을 이용한 시간영역 반사법의 암반변위 계측에의 적용 (Application of Time Domain Reflectometry to the Monitoring or Rock Mass Deformation with Coaxial Cable)

  • 정슬람;정소걸;정현기;박철환;박철환;이희근
    • 터널과지하공간
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    • 제6권4호
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    • pp.306-315
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    • 1996
  • This paper presents an application of the TDR(Time Domain Reflectometry) to the monitoring of the deformation of rock mass with grouted coaxial cables through laboratory tests. The grouted cable can easily deform together with the rock mass movements, and the deformed cable loses its original capacitance and the reflected waveform produced along the deformed cable consequently represents a change of voltage pulse. Therefore, it is possible to monitor the deformation of rock mass by measuring the changes in these reflection signatures. Shear test of the cemented mortar containing a specimen of coaxial cable showed that the shear deformation correlated linearly with the reflection coefficient, so the TDR was effective to monitor the displacement of the rock mass. Bending test were carried out in order to determine the influence of the crooked cables on the monitoring of rock mass movements. Controlled cirmping and shearing test upon a cable of 50 m long, 12.7 mm diameter showed not only the fact that the reflection amplitudes decreased as the cable length increased but also the proper crimping depth, width and interval between two adjacent crimps. Two coaxial cables-one 100 m long and other 175m long-were installed and grouted into the separate boreholes drilled in a sedimentary formation. The behavior of the cable was monitored with metallic TDR cable tester to measure rock mass deformation based on the interpretative techniques developed through laboratory tests.

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대중운동의 파시즘적인 폭력의 가능성과 그에 대한 아도르노의 비판 (Adorno's critique of the possibility of fascist violence in popular movements)

  • 김진애
    • 철학연구
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    • 제144권
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    • pp.141-166
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    • 2017
  • 아도르노가 대중운동에서 가장 중요하게 비판하고 있는 지점은 혁명 지도자와 추종자의 동일성이다. 그 동일화 작업은 세 가지의 특징을 가진다. 첫 번째 특징은 실제의 적대자보다 더 한 이미지를 만들어 적과 동지의 구분을 확실하게 해 집단 내에 연대감을 조성하는 것이다. 이렇게 연대감에 의해 조성된 대중 안에서 저항하는 개별적 주체들은 사라지고 집단과 동일화된 주체만이 존재하게 된다. 두 번째 특징은 낙관주의적인 유토피아를 제시해 대중이 초월적 가치로부터 구원이 도래한다고 믿게 만드는 것이다. 또한 이러한 대중운동은 본인이 속한 연대에 어긋난다고 여겨지는 다른 집단이나 사람들에 대해 논의 과정 없이 비난하는 데에 그친다. 세 번째 특징은 나르시시즘을 기반으로 한 대중 최면상태를 통해 개별적 주체가 사라진 대중이 지휘자들과 동일화 되어 다른 주체들에게 자신이 걸린 최면상태를 강요하는 것이다. 본 논문의 목적은 아도르노가 대중운동의 파시즘적인 폭력에 대해 어떻게 비판하고 있는지 살펴보고 대중운동의 과제에 대해 어떤 것을 제시하고 있는지 분석하는 것이다.

개폐식 지붕구조의 움직임에 대한 공간구조물의 진동해석 (Vibration Analysis of Space Structure with Retractable Roof)

  • 김기철;강주원;김현수
    • 한국공간구조학회논문집
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    • 제11권1호
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    • pp.113-120
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    • 2011
  • 지붕구조의 개폐가 가능한 체육시설 및 복합시설은 대공간구조물의 장점을 잘 나타내고 있으며 대공간구조물의 전천후 사용이 가능하도록 하였다. 개폐식 지붕구조는 구조형식, 마감재료, 개폐방식에 따라서 매우 다양하며 개폐방식에 따라서 중첩방식, 수평이동방식, 주름접기방식 등으로 구분할 수 있다. 특히 중첩방식이나 수평이동방식에 의한 지붕구조의 움직임은 주행하중, 충격하중, 관성력 및 제동력과 같은 동적하중이 구조물에 가해질 수 있으므로 이에 대한 대공간구조물의 진동해석이 필요할 것으로 사료된다. 지붕구조의 움직임에 의한 주행하중은 이동질량 또는 이동하중으로 적용할 수 있으나 비교적 움직임이 느린 개폐식 지붕구조에 의한 동적하중은 아동하중으로 적용하는 것이 타당하다. 따라서 본 논문에서는 지붕구조의 개폐로 야기되는 이동하중에 대한 새로운 적용방법을 제안하고 이를 이용하여 개폐식 지붕의 개폐속도에 따른 대공간구조물의 진동해석을 수행하였다. 본 논문에서 제안된 등가 이동하중은 지붕구조 개폐에 의한 대공간구조물의 진동해석에 있어서 매우 용이하게 활용할 수 있다.

지반굴착과 주변 구조물 손상평가 - 기본개념 (Excavation and Building Damage Assessment - Fundamentals)

  • 유충식
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2002년도 봄 학술발표회 논문집
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    • pp.263-270
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    • 2002
  • During deep excavation, changes in the state of stress in the ground mass around the excavation and subsequent ground losses inevitably occur. These changes in the stress and ground losses are reflected on surrounding ground in the form of ground movements, which eventually Impose strains onto nearby structures through translation, rotation, distortion, and possibly damage. A substantial portion of the cost of deep excavations in urban environments is, therefore, devoted to prevent ground movements. Prediction of ground movements and assessment of the risk of damage to adjacent structures has become an essential part of the planning, design, and construction of a deep excavation project in the urban environments. This paper presents excavation-induced ground movement characteristics as well as important issues related to excavation-induced building damage assessment.

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산지(山地)의 Mass Soil Movement 현상(現象)의 몇 가지 특성(特性) (Characteristics of the Mass Soil Movement Events)

  • 우보명
    • 한국산림과학회지
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    • 제15권1호
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    • pp.49-60
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    • 1972
  • 1972년(年) 8월(月) 18, 19 양일간(兩日間)의 호우(豪雨)(424.1mm)시(時)에 산지(山地)의 단위면적내(單位面積內)에 붕괴발생지(崩壞發生地)가 많았던 안성천유역(安城川流域)의 동북지역(東北地域) 약(約) 20,750 ha의 산지(山地)에서 발생(發生)된 mass soil movement 현상(現象)의 몇 가지 특성(特性)을 조사분석(調査分析)하였다. 결정편암지대(結晶片岩地帶)에서는 계안(溪岸)에 안상(岸狀) 및 여상붕괴(鑢狀崩壞)가, 또 화강암지대(花崗巖地帶)에서는 중상복부(中上腹部)에서 토석유형(土石流型)의 선상(線狀), 판상(板狀) 및 패각상산붕(貝殼狀山崩)이 많이 발생(發生)되었으며, 또 유립목지(有立木地)나 독나지(禿裸地)에서 보다도 치수(稚樹) 유령목지(幼齡木地) 및 척악임지(瘠惡林地)에서 많이 발생(發生)되었다. 평행사면(平行斜面)이나 상승사면(上昇斜面)에서 보다도 하강사면(下降斜面)이나 복합사면(複合斜面)에서, 특(特)히 변곡천이점부위(變曲遷移點部位)에서 많이 발생(發生)되었으며, 산록(山麓)에서 산중복부위(山中腹部位)보다도 중복(中腹)에서 상복(上腹)에 이르는 주곡(主谷)의 최상부(最上部) 분곡부위(分谷部位)에서 가장 많이 발생(發生)되었다. 이 연구결과(硏究結果) 예방치산계획수립(豫防治山計劃樹立)에 필요(必要)한 황폐위험지역(荒廢危險地域)의 판정(判定)에 유용(有用)한 자료(資料)가 될 것이다.

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성대의 비선형 2-mass 디지털 모델 구현 (Implementation of nonlinear two-mass vocal folds digital model)

  • 이희승;정명진
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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    • pp.9-11
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    • 2004
  • The vocal folds play an important role to produce glottal pulse which is an essential factor of phonation. There have been some models which implement the vocal folds' dynamics, such as one-mass model, two-mass model, multi-mass model and ribbon model. Among them, this paper uses nonlinear two-mass model, which is simple structure and produces similarly real glottal pulses and vocal folds' vibration, to realize vocal folds digital model. The pattern of movements in vocal folds will be shown in this paper by using vocal folds digital model. It will be verified how initial position of vocal folds. variation of tension and change of lung pressure influences vibration and glottal pulses.

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근대건축 형성기 영국과 독일의 건축이론 비교 연구 -러스킨과 무테지우스의 이론을 중심으로- (John Ruskin and Herman Muthesius - A Comparative Study on the Architectural Theories of the Early Modern Movements in Britain and Germany -)

  • 김봉열
    • 건축역사연구
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    • 제1권2호
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    • pp.116-136
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    • 1992
  • Architectural essence of John Ruskin's discourse can resolve itself into natural beauty, craftmanship, and truth in structure, surface, and process. His theories became disciplines of modern English school, Art and Craft and Free architecture, in aspects of organic architecture, morality, and rationality. These concepts disseminated continental Art Nouveau and also became it's basic principles. But his empirical theories hated use of machine, and should find a ideal model in medieval romanticism of Gothic. Anti-machine, as a instictive guideline of English modern architecture, couldn't cope with the industrialization of 20th century, and Gothic revival interfered with creating a new style. Muthesius' discourses were taught by the power of group movements and modern concept of form in English school, originally by Ruskin. But he accepted the potentiality of machine and mass production, and stressed creating the new German style suitable with machine. With the progress of Deutscher Werkbund, his theories were advanced to 'quality' connected with craftmanship, to discourse on mechanical 'form', and lastly to 'standardization and type' for mass production. Mechanical functionalism of Muthesius and DWB were sophiscated and handed down to Bauhaus, and then finally helped establishment of the Modern Architecture and Internationalism. Both English and German modern architecture owed their contribution as well as limitation to Ruskin and Muthesius as theorists. Through this comparative study, we can see the priority of theory to practice, the theoretical justification based on insight for its society and future, and the practical character of theory itself.

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