• Title/Summary/Keyword: Numerical Calculation

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An approach for deformation modulus mechanism of super-high arch dams

  • Wu, Bangbin;Niu, Jingtai;Su, Huaizhi;Yang, Meng;Wu, Zhongru;Cui, Xinbo
    • Structural Engineering and Mechanics
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    • v.69 no.5
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    • pp.557-566
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    • 2019
  • The reservoir basin bedrock produced significant impact on the long-term service safety of super-high arch dams. It was important for accurately identifying geomechanical parameters and its evolution process of reservoir basin bedrock. The deformation modulus mechanism research methods of reservoir basin bedrock deformation modulus for super-high arch dams was carried out by finite element numerical calculation of the reservoir basin bedrock deformation and in-situ monitoring data analysis. The deformation modulus inversion principle of reservoir basin bedrock in a wide range was studied. The convergence criteria for determining the calculation range of reservoir basin of super-high arch dams was put forward. The implementation method was proposed for different layers and zones of reservoir basin bedrock. A practical engineering of a super-high arch dam was taken as the example.

Guided Wave Calculation and Its Applications to NDE

  • Hayashi, Takahiro
    • Journal of the Korean Society for Nondestructive Testing
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    • v.24 no.2
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    • pp.125-135
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    • 2004
  • This paper describes the calculation technique for guided wave propagation with a semi-analytical finite element method (SAFEM) and shows some results of numerical calculation and guided wave simulation for plates, pipes and railway rails. The SAFEM calculation gives dispersion curves and wave structures for bar-like structures. Dispersion curve software for a pipe is introduced, and also dispersion corves for a rail are given and experimentally verified. The mode conversions in a plate with a defect and in a pipe with an elbow or a defect are shown as examples of our guided wave simulations.

Self-Tuning Control of Multivariable System (다변수 시스템의 자기동조제어)

  • Lee, D.C.
    • Journal of Power System Engineering
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    • v.3 no.4
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    • pp.69-78
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    • 1999
  • In the single-input and single-output system, the parameter of plant is scalar polynomial, but in the multiple input and multiple output, it accompanies, being matrix polynomial, the consideration of observable controlability index or problems non-commutation in matrix polynomial as well as degree, and it is more complex to deal with. Therefore, it is thought that a full research on the single-input and single-output system is not sufficient. This paper proposes that problems of minimum variance self-tuning regulator by using numerical calculation example of multivariable system and pole assignment self-tuning regulator.

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An Analysis of the acoustic source and radiation acoustic field of centrifugal fans (원심팬 음원 및 방사 음향장 해석)

  • Jeon, Wan-Ho;Lee, Duck-Joo
    • 유체기계공업학회:학술대회논문집
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    • 1998.12a
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    • pp.97-104
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    • 1998
  • The objective of this study is to understand the generation mechanism of sound and to develop a prediction method for the unsteady flow field and the acoustic pressure field of a centrifugal fan. Lowson's method is used to predict the acoustic pressure in a free field. A DVM(discrete vortex method) is used to model the centrifugal fan and to calculate the flow field. In order to compare the experimental data, a centrifugal fan and wedge introduced by Weidemann are used in the numerical calculation and the results are compared with the experimental data.

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Development of Numerical Calculation Software for OTF from Lens Design Data (광학설계제원으로부터의 OTF 수치계산 S/W 개발)

  • 이종웅
    • Korean Journal of Optics and Photonics
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    • v.4 no.4
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    • pp.381-389
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    • 1993
  • A software to calculate diffraction OTF from lens design data was developed and its accuracy was verified. To verify the accuracy, MTF of a standard lens system for OTF measurement were calculated. The results were compared with calculated values by another commercial software and measured values. We found that they have good agreements with one another.

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Heat Transfer Characteristics of a Circular Fin-tube Heat Exchanger (원형휜-원형관의 열전달 특성)

  • 강희찬;조동영;강민철
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.9
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    • pp.762-767
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    • 2003
  • An experimental study was conducted to investigate the heat transfer characteristics of a circular finned-tube heat exchanger. The nineteen cases of configuration varying fin material, fin outer diameter and fin pitch were tested by means of the experiment and the numerical calculation. The measured heat transfer data for the circular finned-tube heat exchanger were provided. A transition of heat transfer was found in the case of low fin pitch. The thermal conductivity of fin affected on the pure heat transfer coefficient.

Flow Characteristics of Photo Resist in a Slit-Coater Nozzle (Slit-Coater 노즐에서 Photo Resist의 유동 특성)

  • 김장우
    • Journal of the Semiconductor & Display Technology
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    • v.3 no.3
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    • pp.37-40
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    • 2004
  • This study presents numerical solutions of three-dimensional laminar flow-field formed by photo resist flow in a slit-coater model. We discuss on the governing equations, laminar viscosities and the computational model applied in our numerical calculation and some results. We prove that the structure of tapered-cavity aid to make uniform pressure-field and boundary effect is an important problem to improve coating uniformity. In view of uniformity improvement, it is necessary to study for the structure of cavity and flow path.

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Design of Integrated-Mirror Etalons for Surface-Emitting Lasers and Photonic Switching (광스위칭과 표면 발진 레이저를 위한 집적 거울 Etalon의 설계)

  • 정종술;윤태훈;김재창
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.3
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    • pp.41-46
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    • 1992
  • In this paper we report how to design integrated-mirror etalons for surface-emitting lasers and photonic switching without time-consuming numerical calculation. It consists of the following two-step process (step 1) find the minimum reflectance to achieve the maximum allowable linewidth. (step 2) find the number of the quarter-wave layers in each mirror to realize the reflectance given by step 1. The condition for maximum transmission in an integrated- mirror etalon is also derived. Under this condition we can achieve the required linewidth with the minimum number of quarterwave layers.

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Design of the gate drive circuit for floating MOSFET using the pulse transformer (펄스 변압기를 이용한 비접지 MOSFET의 게이트 구동 회로 설계)

  • Park, Chong-Yeun;Lee, Bong-Jin
    • Journal of Industrial Technology
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    • v.27 no.B
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    • pp.15-20
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    • 2007
  • This paper presents the new design method for the gate driver circuit of the floating MOSFET by using the pulse transformer. Each parameters of the proposed circuit are delivered by the numerical calculation method. By considering inner characteristics of MOSFET, the gate driver makes to increase the efficiency of the power conversion and decrease operating heat. Computer simulations and to experimental results for a Buck Converter are presented in order to validate the proposed method.

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Finite Difference Analysis of Safe Load and Critical Time in a Four-Parameter Viscoelastic Column

  • Shin, Jong-Gye;Lee, Jae-Yeul
    • Journal of Hydrospace Technology
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    • v.2 no.2
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    • pp.80-87
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    • 1996
  • A creep-buckling analysis is studied for a simply-supported viscoelastic column. The fluid-type four-parameter model is employed because of its general applicability to creep materials. Using the imperfection-based incremental approach, a nonlinear load deflection equation is derived. Safe load and critical (or life) time which characterize the stability of the viscoelastic column are obtained mathematically and interpreted physically. A finite difference algorithm is applied to solve the second-order differential equation of the viscoelastic stress-strain relation. Numerical calculation has been made and discussed far a SUS316 stainless steel column.

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