• 제목/요약/키워드: macroscopic

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국소장이 원자계에 미치는 영향에 대한 이론 II: 이준위 원자계에서의 거시 양자 Langevin 방정식의 유도 (Effect of local field on atomic systems II : Derivation of macroscopic quantum Langevin equations in two-level systems)

  • 안성혁
    • 한국광학회지
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    • 제14권1호
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    • pp.103-106
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    • 2003
  • 쌍극자들로 이루어진 이준위계의 해밀토니안이 주어질 때 이 계가 만족시키는 미시적인 양자 Langevin방정식을 유도하고, 이 방정식을 거시적인 구간 내에서 평균 함으로써 거시 양자 Langevin방정식을 유도하고 국소장 효과가 양자적으로 어떻게 표현되는 지를 살펴본다.

캐비티-유도된 원자측정 장치 (A Cavity-Assisted Atom Detector (CAAD))

  • Chough, Young-Tak;Hyuncheol Nha;Kyungwon An
    • 한국광학회:학술대회논문집
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    • 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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    • pp.124-125
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    • 2000
  • We introduce a scheme with a maximized efficiency of detecting atoms passing through an optical standing-wave mode cavity. Consider a standing-wave optical cavity illuminated by a weak probe beam through one of its mirrors where the transmission through the other mirror is monitored by a photodetector. If an atom is put in the cavity, the atom-cavity coupling shifts the resonance frequency of the system via the so-called normal mode splitting, and thereby the transmission power will drop. In fact, this type of atom detection scheme has been used in recent single atom trap experiments In practice, however, the field in a standing-wave mode will have a geometrical structure having nodes and antinodes that when the atom traverses the cavity through one of the nodes, there will be no such effect of atom-field interaction. (omitted)

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육미지황탕 가미방 투여로 호전된 소아 재발성 혈뇨 1례 (A Case Report of Treating Recurrent Hematuria in Childhood by Yukmijihwangtang-gamibang)

  • 이선정;박은정
    • 대한한방소아과학회지
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    • 제31권2호
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    • pp.57-63
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    • 2017
  • Objectives The purpose of this case study is to report the effect of Yukmijihwangtang-gamibang on recurrent hematuria in childhood. Methods The subject was a male child with macroscopic hematuria. This patient was only treated with oriental herbal medicine. The improvement was observed by subjective symptoms and routine urinalysis. Results After the treatment with Yukmijihwangtang-gamibang, the symptoms of macroscopic hematuria were relieved. The occult blood test was negative as well. The number of red blood cells in urine was within the normal range. He was less tired but hematuria did not recur even after intense exercise. Conclusions This study showed that Korean medical treatment with using herbal medicine such as Yukmijihwangtanggamibang can be an effective treatment option for asymptomatic macroscopic hematuria.

초크랄스키 실리콘 단결정에서 인상 속도의 거시적 변동이 OSF-링 형성에 미치는 영향 (Effect of a Macroscopic Fluctuation in Pulling Rate on the Formation of OSF-ring Cz-Si SIngle Crystal)

  • 박봉모;서경호;김건
    • 한국결정학회지
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    • 제11권3호
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    • pp.157-161
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    • 2000
  • In a 200nm Cz-Si crystal, a macroscopic fluctuation in pulling rate was intentionally introduced an then the variations of the pulling rate and the position of OSF-ring were compared each other. The formation behavior of OSF-ring in the effective volume, defined as the region between the growth interface position -α and the growth interface position +α, is most affected by the pulling rate fluctuation. To understand the correct effect of a macroscopic pulling rate fluctuation, its cumulative effect in the effective volume should be considered. A new concept of modeling for it was proposed here.

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Numerical study on the influence of mesomechanical properties on macroscopic fracture of concrete

  • Zhu, W.C.;Tang, C.A.;Wang, S.Y.
    • Structural Engineering and Mechanics
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    • 제19권5호
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    • pp.519-533
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    • 2005
  • The numerical simulations on the influence of mesoscopic structures on the macroscopic strength and fracture characteristics are carried out based on that the concrete is assumed to be a three-phase composite composed of matrix (mortar), aggregate and bond between them by using a numerical code named MFPA. The finite element program is employed as the basic stress analysis tool when the elastic damage mechanics is used to describe the constitutive law of meso-level element and the maximum tensile strain criterion and Mohr-Coulomb criterion are utilized as damage threshold. It can be found from the numerical results that the bond between matrix and aggregate has a significant effect on the macroscopic mechanical performance of concrete.

거시적 모델을 다르게 고려한 철근콘크리트 벽체의 비선형 해석 연구 (Research on the Non-linear Analysis of Reinforced Concrete Walls Considering Different Macroscopic Models)

  • 신지욱;김준희;유영찬;최기선;김호룡
    • 한국지진공학회논문집
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    • 제16권5호
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    • pp.1-11
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    • 2012
  • 본 연구에서는 주기하중에 대하여 거시적 모델링 방법을 다르게 적용하여 철근콘크리트 벽체의 비선형 해석을 수행하고 기존에 나타난 실험 연구와 비교/분석하였다. ASCE41-06에서 제시하는 높이-길이 비에 따른 벽체의 파괴유형을 참고하여 기존에 수행된 실험연구 중에서 높이-길이비가 3.0을 초과하는 세장한 벽체와 높이-길이비가 1.5인 낮은 벽체를 선택하였다. 각 실험체에 대하여 거시적 모델을 다르게 고려하여 비선형 해석을 수행하였다. 본 연구에서 적용한 거시적 모델은 휨에 대한 거동을 정확히 묘사할 수 있는 방법과 벽체의 복부에서 발생되는 대각 전단을 고려할 수 있는 방법이다. 세장한 벽체는 거시적 모델에 따른 실험과 해석의 결과 차이가 거의 없는 것으로 나타났지만 낮은 벽체는 모델링 방법에서 고려할 수 있는 요소에 의해 이력 거동이 크게 달라지는 것으로 조사되었다. 또한, 높이-길이 비가 1.5인 철근콘크리트 벽체가 건축물에 적용된 경우 정확한 횡 저항능력을 평가하기 위해서 복부의 대각 압축 전단을 고려할 수 있는 모델을 사용하는 것이 타당하다.

승용차환산 계수에 관한 이론적 연구 (A Theoretical Study on Passenger Car Eguivalent Factors)

  • 박창호;김동녕
    • 대한교통학회지
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    • 제9권2호
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    • pp.5-26
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    • 1991
  • Concepts of passenger car equivalent(PCE) based on various philosophies is reviewed. The headway method is redefined in two ways namely a macroscopic headway method and a microscopic headway method of which the concepts are confused in literature. As definition of the microscopic headway method is from intuitive approach so theoretical basis for this method is explained in connection with the macroscopic headway method. In addition new classification and evaluation of complicated existing theories was conducted to make the reader understand more easily.

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화포추진제의 거시적 연소모델에 대한 연구 (A Study on the Macroscopic Combustion Models of Gun Propellants)

  • 윤재건;현형수
    • 대한기계학회논문집
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    • 제18권8호
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    • pp.2201-2209
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    • 1994
  • Macroscopic combustion models used in gun interior ballistic codes are discussed and experimental methods to measure propellant burning rate are reviewed. Comparing with gun firing results, the limit of combustion model is shown and modified combustion model is proposed. But combustion model should be selected with respect to total gun system including propellants.

Determination of the linear elastic stiffness and hygroexpansion of softwood by a multilayered unit cell using poromechanics

  • Gloimuller, Stefan;de Borst, Karin;Bader, Thomas K.;Eberhardsteiner, Josef
    • Interaction and multiscale mechanics
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    • 제5권3호
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    • pp.229-265
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    • 2012
  • Hygroexpansion of wood is a known and undesired characteristic in civil engineering. When wood is exposed to changing environmental humidity, it adsorbs or desorbs moisture and warps. The resulting distortions or - at restrained conditions - cracks are a major concern in timber engineering. We herein present a multiscale model for prediction of the macroscopic hygroexpansion behavior of individual pieces of softwood from their microstructure, demonstrated for spruce. By applying poromicromechanics, we establish a link between the swelling pressure, driving the hygroexpansion of wood at the nanoscale, and the resulting macroscopic dimensional changes. The model comprises six homogenization steps, which are performed by means of continuum micromechanics, the unit cell method and laminate theory, all formulated in a poromechanical framework. Model predictions for elastic properties of wood as functions of the moisture content closely approach corresponding experimental data. As for the hygroexpansion behavior, the swelling pressure has to be back-calculated from macroscopic hygroexpansion data. The good reproduction of the anisotropy of wood hygroexpansion, based on only a single scalar calibration parameter, underlines the suitability of the model. The multiscale model constitutes a valuable tool for studying the effect of microstructural features on the macroscopic behavior and for assessing the hygroexpansion behavior at smaller length scales, which are inaccessible to experiments. The model predictions deliver input parameters for the analysis of timber at the structural scale, therewith enabling to optimize the use of timber and to prevent moisture-induced damage or failure.