• Title/Summary/Keyword: anomalous behavior

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Effects of Surface Treatment of Cathode Materials on the Electrodeposition Behavior of Fe-Ni Alloy (표면처리와 전극 재료가 철-니켈 합금 도금에 미치는 영향)

  • Kang, Na Young;Lee, Jae Ho
    • Journal of the Microelectronics and Packaging Society
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    • v.29 no.4
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    • pp.71-75
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    • 2022
  • In this research, Fe-Ni alloy films were electrodeposited on stainless steel (SS304 and SS430) and Ti plates to investigate the effects of surface conditions of cathode on deposits. The Ti plates were electropolished in 3 M H2SO4-methanol electrolytes at various conditions before electrodeposition, and unpolished Ti and the optimized specimen, polished at 10 V for 8 min, were used as cathode. The anomalous codeposition, the phenomenon which more active Fe is reduced preferentially, occurred on all substrate, however, there were differences in composition of all deposits. As the results of potential monitoring during electrodeposition, it was confirmed that the larger overpotential was applied to the deposition cell when using Ti cathode, leading to high Fe content of deposits from unpolished Ti due to increase in nucleation of Fe. Also, it was founded that the polished Ti can reduced deposition overpotential.

Warping Analysis of Unsymmetric Laminated Composites (비대칭 복합적층판 의 Warping 해석)

  • 전완주;홍창선
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.7 no.4
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    • pp.404-409
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    • 1983
  • The warping of unsymmetric laminated composites is induced by residual curing stress at the room temperature. Classical lamination theory (C.L.T.) predicts the room temperature shapes of all unsymmetric laminates to be a saddle. Experimental observations, however, indicate some unsymmetric laminated composites have cylindrical room temperature shapes. This anomalous behavior is explained by the extention of C.L.T. which involves Von Karman's large deflection theory. It is shown that, depending on the thickness, width, length, curing temperature and room temperature of the laminate, critical boundaries of the shape change are determined. Theoretical predictions are compared with experimental results of Toray Graphite/Epoxy {O$_{n}$/90$_{n}$}$_{T}$./....

Development of stamping analysis process for formability prediction of aluminum alloy sheets (알루미늄판재 성형성 예측을 위한 평면이방성 해석기술개발)

  • Kim, Y.G.;Chung, W.J.;Kim, S.T.;Moon, M.S.;Yoon, J.W.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.304-307
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    • 2006
  • A plane stress yield function YLD2000(Yoon et al., 2000) is applied to the finite element analysis S/W Z-Stamp because it is required to conduct proper consideration of aluminum alloy which has anomalous behavior. In the previous study, verification of the yield function and developed S/W is implemented. In this paper, two real parts of automobile body are additionally considered to verify the validity of Z-Stamp. The one is the benchmark problem #2 of Numisheet 2005 and the other is a small member part. In case of benchmark problem, formability simulation result and try-out result are compared with each other. In case of the small member part, formability analysis is implemented to predict the problem during the developing time.

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Sectional Forming Analysis of Stamping Processes for Luminum Alloy Sheet metals (알루미늄 합금 박판 스탬핑 공정의 단면 성형 해석)

  • 이광병;이승열;금영탁
    • Transactions of Materials Processing
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    • v.6 no.4
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    • pp.279-290
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    • 1997
  • The sectional forming analysis of stamping pocesses for aluminum alloy sheet metals was investigated. For the modeling of the anomalous behavior of aluminum alloy sheet. the Barlat's strain rate potential and Hill's 1990 non-quadratic yield theory with an isotropic hardening rule were employed. The rigid-viscoplastic FEM formulation which solves equilibrium equation for plane-strain stage with mesh-normal geometric constraints was derived. A new method to determine the Barlat's anisotropic coefficients was also suggested. To verify the validity of the formulation, the stretch and draw forming processes of a square cup were simulated.

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Statistical and Entropy Based Human Motion Analysis

  • Lee, Chin-Poo;Woon, Wei-Lee;Lim, Kian-Ming
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.4 no.6
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    • pp.1194-1208
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    • 2010
  • As visual surveillance systems gain wider usage in a variety of fields, it is important that they are capable of interpreting scenes automatically, also known as "human motion analysis" (HMA). However, existing HMA methods are too domain specific and computationally expensive. This paper proposes a general purpose HMA method that is based on the idea that human beings tend to exhibit erratic motion patterns during abnormal situations. Limb movements are characterized using the statistics of angular and linear displacements. In addition, the method is enhanced via the use of the entropy of the Fourier spectrum to measure the randomness of subject's motions. Various experiments have been conducted and the results indicate that the proposed method has very high classification accuracy in identifying anomalous behavior.

Transonic flow past a Whitcomb airfoil with a deflected aileron

  • Kuzmin, Alexander
    • International Journal of Aeronautical and Space Sciences
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    • v.14 no.3
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    • pp.210-214
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    • 2013
  • The sensitivity of transonic flow past a Whitcomb airfoil to deflections of an aileron is studied at free-stream Mach numbers from 0.81 to 0.86 and vanishing or negative angles of attack. Solutions of the Reynolds-averaged Navier-Stokes equations are obtained with a finite-volume solver using the $k-{\omega}$ SST turbulence model. The numerical study demonstrates the existence of narrow bands of the Mach number and aileron deflection angles that admit abrupt changes of the lift coefficient at small perturbations. In addition, computations reveal free-stream conditions in which the lift coefficient is independent of aileron deflections of up to 5 degrees. The anomalous behavior of the lift is explained by interplay of local supersonic regions on the airfoil. Both stationary and impulse changes of the aileron position are considered.

Anomalous superconducting spin-valve effect in NbN/FeN/Cu/FeN/FeMn multilayers

  • Hwang, Tae Jong;Kim, Dong Ho
    • Progress in Superconductivity and Cryogenics
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    • v.19 no.3
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    • pp.23-26
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    • 2017
  • We have studied magnetic and transport properties of NbN/FeN/Cu/FeN/FeMn spin-valve structure. In-plane magnetic moment exhibited typical hysteresis loops of spin valves in the normal state of NbN film at 20 K. On the other hand, the magnetic hysteresis loop in the superconducting state exhibited more complex behavior in which exchange bias provided by antiferrmagnetic FeMn layer to adjacent FeN layer was disturbed by superconductivity. Because of this, the ideal superconducting spin-valve effect was not detected. Instead the stray field originated from unsaturated magnetic states dominated the transport properties of NbN/FeN/Cu/FeN/FeMn multilayer.

Corrosion Fatigue Cracking of Low Alloy Steel in High Temperature Water

  • Lee, S.G.;Kim, I.S.;Jang, C.H.;Jeong, I.S.
    • Corrosion Science and Technology
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    • v.2 no.2
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    • pp.93-97
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    • 2003
  • Fatigue crack growth test or low alloy steel was performed in high temperature water. Test parameters were dissolved oxygen content. loading frequency and R-ratio ($P_{min}/P_{max}$). Since the sulfur content or the steel was low, there were no environmentally assisted cracks (EAC) in low dissolved oxygen(DO) water. At high DO, the crack growth rate at R = 0.5 tests was much increased due to environmental effects and the crack growth rate depended on loading frequency and maximized at a critical frequency. On the other hand, R = 0.7 test results showed an anomalous decrease of the crack growth rate as much different behavior from the R = 0.5. The main reason of the decrease may be related to the crack tip closure effect. All the data could be qualitatively understood by effects of oxide rupture and anion activity at crack tip.

Effects of Sb2O3 on the PTCR Properties of (Ba,Sr)TiO3-based Ceramics ((Ba,Sr)TiO3계 세라믹스의 PTCR 특성에 미치는 Sb2O3의 영향)

  • Lee Ho-Won;Kim Young-Min;Ur Soon-Chul;Kim Il-Ho
    • Korean Journal of Materials Research
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    • v.14 no.2
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    • pp.115-120
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    • 2004
  • Perovskite barium-strontium titanate, $(Ba, Sr)TiO_3$ was prepared and effects of $Sb_2$O$_3$ additives on its PTCR properties were investigated. $The (Ba,Sr)TiO_3$ with 0.05~0.25 mol% $Sb_2$$O_3$ showed semiconducting PTCR behavior and anomalous grain growth was also observed when it was sintered above $1330^{\circ}C$. It was considered that charge compensation by doping 8b203 as well as abnormal grain growth by sintering lead to resistivity reduction from insulating to semiconducting transition.

ANOMALOUS HALL EFFECT IN AMORPHOUS $Fe_{0.33}Zr_{0.67}$ ALLOY

  • Rhie, K.;Naugle, D.G.
    • Journal of the Korean Magnetics Society
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    • v.5 no.6
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    • pp.952-955
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    • 1995
  • It is well kown that the side-jump effect, originated from the spin-orbit scatterring of the transport electrons at the site of spin-orbit scatterers, is the reason for the anomalus Hall resistivity which is proportional to the magnetization. Our recent magnetization study implied that abundant ferromagnetic Fe clusters made of for Fe ions dominate the temperature and field dependence of magnetization at high field and low temperature regime for a paramagnetic $Fe_{0.33}Zr_{0.67}$ alloy. We measured the Hall resistivity of this alloy and observed that the Hall resistivity followed the M-H cure at low temperature, and the Hall coefficients at moderate temperatures were proportional to the magnetic susceptibility. We explain the behavior of Hall resistivity with the change of field and temperature in terms of side-jump effect.

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