• 한국해안·해양공학회논문집
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• 제25권3호
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• pp.123-127
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• 2013

본 논문에서는 해상풍력발전터빈의 기초형식 중 하나인 버켓기초의 관입시 발생할 수 있는 좌굴거동에 대한 연구를 수행하였다. 유한요소를 사용하여 대상구조물을 모델링하고 현재 설계기준의 기본인 원통형 쉘의 좌굴거동을 해석하여, Batdorf의 계수에 따라 설계기준에 제시된 식과 비교하여 모델의 검증을 수행하였다. 검증된 해석 모델을 바탕으로 인접한 지반의 영향 및 하중조건을 적용하고 종방향보강재와 관입깊이가 좌굴성능에 미치는 영향을 평가하였다. 평가결과 종방향보강재의 적용은 특정영역에서 좌굴강도를 크게 증가시키고 인접한 지반의 영향은 관입에 따라 선형적으로 증가하는 것으로 나타났다.

• Structural Engineering and Mechanics
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• 제72권5호
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• pp.541-555
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• 2019

Wind induced dynamic responses on hyperbolic cooling tower (HCT) shells are complicated functions of structure and wind properties, such as the fundamental frequency f_min, damping ratio ζ, wind velocity V, correlationship in meridian direction and so on, but comprehensions on the sensitivities of the dynamic responses to these four factors are still limited and disagree from each other. Following the dynamic calculation in time domain, features of dynamic effects were elaborated, focusing on the background and resonant components σ_B and σ_R, and their contributions to the total rms value σ_T. The σ_R is always less than σ_B when only the maximum σ_T along latitude is concerned and the contribution of σ_R to σ_T varies with responses and locations, but the σ_R couldn't be neglected for structural design. Then, parameters of the above four factors were artificially adjusted respectively and their influences on the gust responses were illustrated. The relationships of σ_R and the former three factors were expressed by fitted equations which shows certain differences from the existing equations. Moreover, a new strategy for wind tunnel tests aiming at surface pressures and the following dynamic calculations, which demands less experiment equipment, was proposed according to the influence from meridian correlationship.

• 한국강구조학회 논문집
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• 제27권1호
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• pp.119-129
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• 2015

강재량을 줄이면서도 풍하중의 영향을 완화시킬 수 있는 장점으로, 수평재로 서로 연결된 다수의 수직 원형강관으로 구성된 멀티기둥 풍력타워 시스템은 기존의 단일 실린더형 타워구조에 대한 대안으로 고려될 수 있다. 멀티기둥 타워를 하나의 타워구조로 거동하게 하기 위해서는 수직 강관과 수평 강관의 연결부인 강관조인트의 강도 확보가 중요하다. 본 연구에서는 멀티기둥에 적용될 수 있는 T 조인트의 강도평가를 수행하였다. AISC, Eurocode3, ISO 19902, CIDECT의 4가지 강관조인트 설계기준을 검토하고, 조인트에서 주강관과 지강관의 세장비에 대한 매개변수해석을 통하여 설계기준에서 제공되는 강도산정식의 타당성을 검토하였다.

• 한국강구조학회 논문집
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• 제27권1호
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• pp.109-118
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• 2015

풍력발전 타워용 원형단면 강재 쉘에 대하여 재료 및 기하학적 비선형 유한요소법으로 극한휨강도 해석을 수행하였다. 쉘의 기하학적 초기변형, 반경 대 두께비, 적용 강종 등이 극한휨강도에 미치는 영향을 분석하였으며, Eurocode 3와 AISI 설계기준에 의한 설계휨강도와 유한요소해석으로 구한 극한휨강도를 비교하였다. 비선형 FE 해석에는 DNV-RP-C202에 제시된 쉘의 좌굴모드와 유로코드에 규정된 진원도 허용오차 및 용접에 의한 변형을 기하학적 초기 결함으로 고려하였다. 원통형 쉘의 반경 대 두께비는 60~210 범위를 고려하였으며 SM520과 HSB800 강재로 제작된 것으로 가정하였다.

• Wind and Structures
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• 제23권4호
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• pp.313-350
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• 2016

Taipei 101 Tower, which has 101 stories with height of 508 m, is located in Taipei where typhoons and earthquakes commonly occur. It is currently the second tallest building in the world. Therefore, the dynamic performance of the super-tall building under strong wind actions requires particular attentions. In this study, Large Eddy Simulation (LES) integrated with a new inflow turbulence generator and a new sub-grid scale (SGS) model was conducted to simulate the wind loads on the super-tall building. Three-dimensional finite element model of Taipei 101 Tower was established and used to evaluate the wind-induced responses of the high-rise structure based on the simulated wind forces. The numerical results were found to be consistent with those measured from a vibration monitoring system installed in the building. Furthermore, the equivalent static wind loads on the building, which were computed by the time-domain and frequency-domain analysis, respectively, were in satisfactory agreement with available wind tunnel testing results. It has been demonstrated through the validation studies that the numerical framework presented in this paper, including the recommended SGS model, the inflow turbulence generation technique and associated numerical treatments, is a useful tool for evaluation of the wind loads and wind-induced responses of tall buildings.

• 한국정보통신학회논문지
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• 제11권7호
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• pp.1400-1406
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• 2007

정보영재 교육의 핵심 내용은 프로그래밍을 위한 사고력 신장에 있다. 이 논문에서는 교육 프로그램 모형으로 4단계 - 문제이해, 시각화, 기호화, 알고리즘화 - 를 제안한다. 이 4단계의 모형은 트리 구조를 사용한 되부름의 추상적인 개념을 익히도록 하여 '하노이 타워'의 예를 통해 초등정보영재의 지적 호기심을 자극하고 사고력 신장에 크게 도움을 줄 수 있을 것이다. 또한, 초등정보영재라는 교육대상자의 수준과 특성을 고려하고, 프로그램의 유형과 학습내용의 성격, 사고력의 하위 요소를 명확하게 하여 교육 프로그램을 제작함으로써 각각의 주제와 학습 활동에 따라 어떻게 지도해야 하는지를 보다 분명하게 할 수 있다. 학생들이 자기 평가하는 활동을 통해 학습 내용을 보다 심화 발전시킬 수 있으며, 사고력의 신장은 교사의 지도를 통해 보다 강화될 수 있다.

• 대한건축학회논문집:구조계
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• 제35권8호
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• pp.169-176
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• 2019

The purpose of this study was to analyze outdoor thermal comfort of apartments planning characteristic of pedestrian height in Beijing, China. Selecting 322 apartment complexes with more than 1000 households and more than 10 buildings(including 10 buildings), mainly in Chaoyang District and Tongzhou District to select 32 basic layout types and then 12 typical layout types were select in 32 basic layout types. Finally, the simulation was conducted for the 12 typical layout types using the micro-climate model ENVI-met to evaluate the wind environment, the thermal environment and the comfort. The results of this study as follows: In the parallel arrangement, it has the best outdoor thermal comfort of Slab-East-Parallel(S/E/P). Next is Slab-South-Parallel(S/S/P), Tower-South-Parallel(T/S/P) in turn. In the stagger arrangement, Mixture-South-North and South Stagger-1(M/S/NSS-1) has the best outdoor thermal comfort and Slab-South-North and South Stagger(S/S/NSS), Tower-South-North and South Stagger(T/S/NSS), Mixture-South-North and South Stagger-3(M/S/NSS-3), Mixture-South-North and South Stagger-4(M/S/NSS-4), Mixture-South-North and South Stagger-2(M/S/NSS-2) in turn. In the cluster arrangement, Mixture-Mixture-Cluster-2(M/M/C-2) has the best outdoor thermal comfort and Mixture-Mixture-Cluster-3(M/M/C-3), Mixture-Mixture-Cluster-1(M/M/C-1) in turn. Due to the low wind speed and high air temperature, it is necessary to consider the layout types that can form the wind road at first, such as Mixture-South-North and South Stagger-1(M/S/NSS-1), Slab-South-North and South Stagger(S/S/NSS) and so on.

• 영미문화
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• 제10권2호
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• pp.149-207
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• 2010

Written simultaneously with Prometheus Unbound, Shelley's "Julian & Maddalo" is a masterwork of dramatic poiesis, of doubling embedded in its couplets, dialogic debate on human nature and contrasted symbolic emblems. The emblems mirror each other and are themselves sites of generative paradox: the "heaven illumined" but "dreary tower" of the Maniac and the glorious sunsets on the "ever-shifting sand" of the Lido, a wasteland that is a place of self discovery but also of "abandonment" and barren mingling figured, inter alia, in its "amphibious weeds," a trope of the poem's personae. This essay also explores the poem's dramatic structure and various rhetorical devices, beginning with the Preface, a threshold of complex identity disguise that Shelley uses for veiled self-presentation, as in "Alastor," mirroring and literary references replete with nuanced ironies. I focus mainly on the complex figures of liminality Shelley uses to develop his own thoughts (as well as his ongoing debates with Byron) about man's potential for growth in thought, insight and empathy, in political reform and interpersonal and individual healing. Advancing Shelley's most optimistic ideas, Julian, escorted by Maddalo observes the Maniac, -- a living ruin whose pained eloquence reveals the link of eros to poiesis and the limits of the latter's ability to 'transform a world.' The Maniac is the core of muse-work (remembering, thinking and song) and Shelley presents him as its emblem. He also is prefigured in and reflects the quintessentially liminal Lido with its "barren embrace" of sea and land. Yet it is less the Maniac's feeling that his grief is "charactered in vain…on this unfeeling leaf" than Julian's rationales for leaving the site of pain that point to Shelley's final comment on poetry's transformative limits. As the primary haploids of the drama's meiosis re-combine and two of them, Maddalo and the maniac fall away, an analogy I briefly develop and embedded in the erotic dynamics of poiesis, Shelley suggests, as he did at the beginning of his poetic lyricism in "Alastor" and at its end in "the Triumph of Life"that images mislead and delude; that "the deep truth is imageless" and redemption is not in but beyond figuration.

• 공업화학
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• 제32권1호
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• pp.91-96
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• 2021

본 연구에서는 다양한 환경 공정에서 사용되는 황화수소 제거용 흡착탑 효율을 향상시키기 위해 유동 분석 및 흡착성능 향상 연구를 수행하였다. 연구를 위해 상업적으로 이용 가능한 다양한 활성탄에 칼륨(potassium, K)을 담지하여 개질 활성탄을 제조하였다. 또한 열처리 여부에 따라 흡착 성능과 열처리 과정에서 변화된 표면 특성 사이의 높은 상관관계를 고찰하고자 하였다. 함침법을 통해 K로 코팅된 활성탄은 57배 이상의 흡착 성능을 확인하였다. 이는 균일한 기공 형성과 탄소 표면의 K의 강한 결합은 황화수소의 화학적 및 물리적 흡수에 기여한다고 판단하였다. 다양한 상용 활성탄의 표면 구조에 대한 SEM 분석은 열처리를 통한 표면 특성의 변형으로 인해 기공 구조가 파괴되어 흡수 성능이 저하되는 것으로 확인하였다. 각 활성탄의 압력 손실 특성은 입자 크기와 모양에서 가장 낮은 압력 손실이 관찰되었다. 따라서 2~4 mesh 크기의 탄소입자 범위와 불규칙한 모양이 흡착탑의 성능을 향상시키고 경제적 효율성을 확보할 수 있다고 제안하였다.

• Wind and Structures
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• 제37권6호
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• pp.413-423
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• 2023

Wind turbines are usually steel hollow structures that can be vulnerable to dramatic failures due to high-intensity wind (HIW) events, which are classified as a category of localized windstorms that includes tornadoes and downbursts. Analyzing Wind Turbines (WT) under tornadoes is a challenging-to-achieve task because tornadoes are much more complicated wind fields compared with the synoptic boundary layer wind fields, considering that the tornado's 3-D velocity components vary largely in space. As a result, the supporting tower of the wind turbine and the blades will experience different velocities depending on the location of the event. Wind farms also extend over a large area so that the probability of a localized windstorm event impacting one or more towers is relatively high. Therefore, the built-in-house numerical code "HIW-WT" has been developed to predict the straining actions on the blades considering the variability of the tornado's location and the blades' pitch angle. The developed HIWWT numerical model incorporates different wind fields that were generated from developed CFD models. The developed numerical model was applied on an actual wind turbine under three different tornadoes that have different tornadic structure. It is found that F2 tornado wind fields present significant hazard for the wind turbine blades and have to be taken into account if the hazardous impact of this type of unexpected load is to be avoided.