• 제목/요약/키워드: Technology evolution

검색결과 2,186건 처리시간 0.036초

단섬유 금속복합체에서의 소성역 전개과정 및 바우신저 효과에 관한 연구 (A Study on the Evolution of Local Plasticity and the Bauschinger Effects in Short Fiber Reinforced Metal Matrix Composites)

    • 한국생산제조학회지
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    • 제7권1호
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    • pp.22-33
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    • 1998
  • A continuum analysis of the evolution of plasticity and Bauschinger effect in a short fiber reinforced metal matrix composite, based on the FEM solution for a single fiber model has been performed to investigate the strengthening behavior. The evolution of matrix field quantities during one cycle of fully reversed loading have been examined in detail. The results indicate that the role of constrained matrix flow in generating different levels of matrix triaxiality during forward and reversed loading provides an important contribution to the developement of the Bauschinger effect in the metal matrix composite. Therefore, even when the plastic flow of the matrix material follows on isotropic hardening behavior, the Bauschinger effect is predicted for the composite material.

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Fuzzy Controller of Three-Inertia Resonance System designed by Differential Evolution

  • Ikeda, Hidehiro;Hanamoto, Tsuyoshi
    • Journal of international Conference on Electrical Machines and Systems
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    • 제3권2호
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    • pp.184-189
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    • 2014
  • In this paper, a new design method of vibration suppression controller for multi-inertia (especially, 3-ineritia) resonance systems is proposed. The controller consists of a digital fuzzy controller for speed loop and a digital PI controller for current minor loop. The three scaling factor of the fuzzy controller and two PI controller gains are determined by Differential Evolution (DE). The DE is one of optimization techniques and a kind of evolutionary computation technique. In this paper, we have applied the DE/rand/1/bin strategy to design the optimal controller parameters. Comparing with the conventional design algorithm, the proposed method is able to shorten the time of the controller design to a large extent and to obtain accurate results. Finally, we confirmed the effectiveness of the proposal method by the computer simulations.

페라이트계 스테인레스강의 집합조직 형성에 미치는 초기 방위 및 오스테나이트사의 영향 (Effect of Initial Orientation and Austenitic Phase on Texture Evolution in Ferritic Stainless Steels)

  • 이용득
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1999년도 추계학술대회논문집
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    • pp.149-152
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    • 1999
  • The effect of initial orientation on the microstructure and texture evolution of two ferritic stainless steels was investigated. the columnar and equiaxed crystal specimens which were prepared from continuous casting slab were hot rolled annealed cold rolled and annealed respectively. The rolling and recrystallization textures at each process stage were examined by orientation distribution function (ODF) and electron back-scattered diffraction (EBSD); The observation showed that the orientation density of the $\alpha$-fibre of hot rolled band of columnar crystal specimen was more pronounced than that of the equaxed one at the center layer. Nevertheless the cold rolled textures of Type 430 steel have demonstrated a rather similar development . Compared to Type 430 steel the development of the $\alpha$-fibre in the center layer of Type 409L steel was much more pronounced. The relation between texture evolution and ridging behaviour has been discussed.

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${Ni_3}Al-{Ni_3}V$ 준이원계 합금 포함 삼원계 시스템에서의 meso-scale 미세구조의 전산 모사에 관한 연구 (A computer simulation of the peso-scale microstructural evolution in the ternary Ni- ${Ni_3}Al-{Ni_3}V$ system)

  • 박성일;이혁모
    • 한국재료학회지
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    • 제11권11호
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    • pp.947-952
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    • 2001
  • The meso-scale microstructure of the $Ni-Ni_3Al- Ni_3V$ system is crucial to obtain both high strength and high toughness. Its evolution may be predicted with the aid of computer simulation of the compositional separation for heat-treated alloys. In this study, computer simulations of the hypothetical A-B-C ternary system, which is similar to the $Ni-Ni_3Al- Ni_3V$ system in terms of phase equilibria, have been performed using the kinetic modeling. Simulated morphologies were changed with nominal compositions and model parameters. It was showed the current model was useful and the more realistic model was proposed.

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금형강의 동적 및 정적 재결정 거동과 미세조직 변화 예측에 관한 연구 (A Study on Dynamic and Static Recrystallization Behaviors and Microstructure Evolution Prediction of Die Steels)

  • 정호승;조종래;차도진;배원병
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2001년도 춘계학술대회 논문집
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    • pp.131-135
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    • 2001
  • Evaluation of microstructural changes during open die forging of heavy ingots is important for process control. The objective of the control of forging parameters, such as shape of the dies, reduction, temperature and sequence of passes, is to maximize the forging effects md to minimize inhomogeneities of mechanical properties. The hot working die steel is produced by using the multistage open die forging. The structure is altered during forging by subsequent processes of plastic deformation, recrystallization and grain growth. A numerical analysis using an rigid visco-plastic finite element model was performed to predict microstructural evolution of hot working die steel.

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Evolution Strategies Based Particle Filters for Simultaneous State and Parameter Estimation of Nonlinear Stochastic Models

  • Uosaki, K.;Hatanaka, T.
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.1765-1770
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    • 2005
  • Recently, particle filters have attracted attentions for nonlinear state estimation. In this approaches, a posterior probability distribution of the state variable is evaluated based on observations in simulation using so-called importance sampling. We proposed a new filter, Evolution Strategies based particle (ESP) filter to circumvent degeneracy phenomena in the importance weights, which deteriorates the filter performance, and apply it to simultaneous state and parameter estimation of nonlinear state space models. Results of numerical simulation studies illustrate the applicability of this approach.

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Evolution and Design Principles of the Diverse Chloroplast Transit Peptides

  • Lee, Dong Wook;Hwang, Inhwan
    • Molecules and Cells
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    • 제41권3호
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    • pp.161-167
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    • 2018
  • Chloroplasts are present in organisms belonging to the kingdom Plantae. These organelles are thought to have originated from photosynthetic cyanobacteria through endosymbiosis. During endosymbiosis, most cyanobacterial genes were transferred to the host nucleus. Therefore, most chloroplast proteins became encoded in the nuclear genome and must return to the chloroplast after translation. The N-terminal cleavable transit peptide (TP) is necessary and sufficient for the import of nucleus-encoded interior chloroplast proteins. Over the past decade, extensive research on the TP has revealed many important characteristic features of TPs. These studies have also shed light on the question of how the many diverse TPs could have evolved to target specific proteins to the chloroplast. In this review, we summarize the characteristic features of TPs. We also highlight recent advances in our understanding of TP evolution and provide future perspectives about this important research area.

다결정 미세입자 소각입계면에서의 전위밀도 확산 (Dislocation Density Propagation adjacent to the Low Angle Grain Boundaries of Polycrystalline Materials)

  • 마정범
    • 한국생산제조학회지
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    • 제20권5호
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    • pp.618-622
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    • 2011
  • Specialized large-scale computational finite-element and molecular dynamic models have been used in order to understand and predict how dislocation density emission and contact stress field due to nanoindentation affect inelastic deformation evolution scales that span the molecular to the continuum level in ductile crystalline systems. Dislocation density distributions and local stress fields have been obtained for different crystalline slip-system and grain-boundary orientations. The interrelated effects of grain-boundary interfaces and orientations, dislocation density evolution and crystalline structure on indentation inelastic regions have been investigated.

430 스테인리스강의 미세조직 및 집합조직 형성에 미치는 냉간압연 및 소둔조건의 영향 (Effect of Cold Rolling and Annealing Conditions on the Microstructure and Texture Evolution)

  • 김광육
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 춘계학술대회논문집
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    • pp.202-205
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    • 2000
  • The effect of two step cold rolling and intermediate annealing conditions on the microstructure and texture evolution in type 430 stainless steel has been investigated tin order to improve ridging characteristic and deep drawability. The rolling and recrystallization textures were examined by orientation distributionfunction(ODF) and electron backscattered diffraction(EBSD). The observation showed that the intensity of ${\gamma}$-fiber was increased with two-step cold rolling process and so ridging characteristic and deep drawability were considerably improved. The relation between these properties an texture evolution has been discussed.

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Opposition Based Differential Evolution Algorithm for Capacitor Placement on Radial Distribution System

  • Muthukumar, R.;Thanushkodi, K.
    • Journal of Electrical Engineering and Technology
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    • 제9권1호
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    • pp.45-51
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    • 2014
  • Distribution system is a critical link between customer and utility. The control of power loss is the main factor which decides the performance of the distribution system. There are two methods such as (i) distribution system reconfiguration and (ii) inclusion of capacitor banks, used for controlling the real power loss. Considering the improvement in voltage profile with the power loss reduction, later method produces better performance than former method. This paper presents an advanced evolutionary algorithm for capacitor inclusion for loss reduction. The conventional sensitivity analysis is used to find the optimal location for the capacitors. In order to achieve a better approximation for the current candidate solution, Opposition based Differential Evolution (ODE) is introduced. The effectiveness of the proposed technique is validated through 10, 33, 34 and85-bus radial distribution systems.