• Title/Summary/Keyword: Diffusion Length

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Defect evaluation of Fe metallic contamination in silicon wafers (Si 웨이퍼의 내부 금속 불순물 Fe의 결함분석)

  • 오민환;남효덕;김흥락;김동수;김영덕;김광일
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.578-581
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    • 2001
  • Silicon wafers using DRAM devices required for high cleaning technology and this cleaning technology was evaluated by defect level or electron life time. This paper examined the correlation of SPV(Surface Photo Voltaic Analyzer) which analyzes diffusion length of minority carriers and DLTS(Deep level Transient Spectroscope) which analyzes defect level.

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Separative Power of an Optimised Concurrent Gas Centrifuge

  • Bogovalov, Sergey;Borman, Vladimir
    • Nuclear Engineering and Technology
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    • v.48 no.3
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    • pp.719-726
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    • 2016
  • The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to ${\delta}U=12.7(V/700m/s)^2(300K/T)(L/1m)kg{\cdot}SWU/yr$, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

Derivation of dc Voltages in a Magnetic Multilayer Undergoing Ferromagnetic Resonance

  • Oh, Dong-Keun;Lee, Cheol-Eui
    • Journal of Magnetics
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    • v.10 no.3
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    • pp.77-79
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    • 2005
  • In this work, we present a comprehensive and systematic approach for the derivation of the dc voltage generated by a magnetic multilayer undergoing ferromagnetic resonance, originally derived by Berger. Our alternative derivation applies especially in the limit of the spin diffusion length much longer than the carrier mean free path.

An Analysis on the Discharge Characteristics through 1-D Numerical Simulation in an AC PDP (AC PDP에서 1차원 수치해석을 통한 방전 특성 연구)

  • Lee, J.H.;Seo, J.H.;Lee, S.H.
    • Proceedings of the KIEE Conference
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    • 2003.10a
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    • pp.220-222
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    • 2003
  • In this paper, we analyze on the discharge characteristics through 1-D simulations in an at plasma display panel discharge cell. The model is based on a Poisson' equation, continuity and drift-diffusion equation. Results are presented in a 95% neon, 5% xenon gas mixture, for a gap length of 100us and a gas pressure of 400Torr at ambient temperature. Results for other gap length are also discussed. As a result, an increase of the gap cause increase of luminous efficiency but with larger sustaining voltage.

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Effect of Oxygen Enriched Air on the Combustion Characteristics in a Coaxial Non-Premixed Jet ( I ) - Lift-off and Flame Stability - (산소부화공기가 동축 비예혼합 제트의 연소특성에 미치는 영향 (I) - 화염의 부상과 안정성)

  • Kwark, Ji-Hyun;Jeon, Chung-Hwan;Chang, Young-June
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.2
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    • pp.160-166
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    • 2004
  • Combustion using oxygen enriched air is known as a technology which can increase flame stability as well as thermal efficiency due to improving the burning rate. Lift-off, blowout limit and flame length were examined as a function of jet velocity, coflow velocity and OEC(Oxygen Enriched Concentration). Blowout limit of the flame below OEC 25% decreased with increase of coflow velocity, but the limit above OEC 25% increased inversely. Lift-off height decreased with increase of OEC. In particular, lift-off hardly occurred in the condition above OEC 40%. Flame length of the flames above OEC 40% was increased until the blowout occurred. Great flame stability was obtained since lift-off and blowout limit significantly increased with increase of OEC.

Lift-off and Flame Stability of a Coaxial Non-Premixed Jet Using Oxygen Enriched Air (산소부화공기를 이용한 동축 제트화염의 부상과 연소 안정성)

  • Kwark, Ji-Hyun;Jeon, Chung-Hwan;Chang, Young-June
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.326-331
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    • 2003
  • Combustion using oxygen enriched air is known as a technology which can increase flame stability as well as thermal efficiency due to improvement of the burning rate. Lift-off, blowout limit and flame length were examined as a function of jet velocity, coflow velocity and OEC(Oxygen Enriched Concentration). Blowout limit of the flame below OEC 25% decreased with coflow velocity, but the limit above OEC 25% increased inversely. Lift-off height decreased with increase of OEC. Especially lift-off hardly occurred in the condition above OEC 40%. Flame length of the flames above OEC 40% was increased until the blowout occurred. Flame stability became improved since lift-off and blowout limit increased much with increase of OEC.

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Dynamic Heterogeneity in Spin Facilitated Model of Supercooled Liquid: Crossover from Fragile to Strong Liquid Behavior

  • Choi, Seo Woo;Kim, Soree;Jung, YounJoon
    • Proceeding of EDISON Challenge
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    • 2014.03a
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    • pp.183-195
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    • 2014
  • Kinetically constrained models (KCM) have attracted interest as models that assign dynamic origins to the interesting dynamic properties of supercooled liquid. Signs of dynamic heterogeneity in the crossover model that linearly interpolates between the FA-like symmetric constraint and the East model constraint by asymmetric parameter b were investigated using Monte Carlo technique. When the asymmetry parameter was decreased sufficiently, smooth fragile-to-strong dynamic transition was observed in terms of the relaxation time, diffusion constant, Stokes-Einstein violation, and dynamic length scale. Competition between energetically favored symmetric relaxation mechanism and entropically favored asymmetric relaxation mechanism is behind such transition.

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Spin Valve Effect in Lateral Py/Au/Py Devices

  • Ku, Jang-Hae;Chang, Joon-Yeon;Koo, Hyun-Cheol;Eom, Jong-Hwa;Han, Suk-Hee;Kim, Gyu-Tae
    • Journal of Magnetics
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    • v.12 no.4
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    • pp.152-155
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    • 2007
  • Spin dependent transport was investigated in lateral $Py(Ni_{81}Fe_{19})/Au/Py$ spin valve devices. Clear spin valve effect was observed in conventional four-terminal measurement geometry. Higher resistance was found in antiparallel magnetization field of two Py electrodes which is determined by anisotropy magnetoresistance (AMR) measurements. The rectangular shape of spin signal together with good agreement of switching field convinces observed spin valve signal is resulted from effective spin injection and detection. The magnetoresistance ratio decays exponentially with channel length by which spin diffusion length of Au channel was estimated to be 76 nm.

Operation of Electrodialysis at Over Limiting Current Density (한계전류밀도 이상에서 전기투석공정의 운전)

  • 박진수;최재환;문승현
    • Membrane Journal
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    • v.12 no.3
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    • pp.171-181
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    • 2002
  • The parameter which determines the plateau length of current-voltage curve for ion- exchange membranes was studied at various concentrations of NaCl and different flow rates. Moreover, the feasibility of the electrodialytic removal of 0.1 M NaCl solution at various current densities was tested by assessing the electrodialysis performance parameters such as salt removal efficiency, current efficiency, energy consumption and water dissociation. The diffusion boundary layer (DBL) thickness decreased with the NaCl concentration and flow rate of fled solution and it was observed that the plateau length of current-voltage curves was related with the DBL thickness. The removal efficiency and current efficiency were not affected significantly by the current densities even at the overlimiting current region indicating that most current were passed by electrolyte, and water dissociations are not responsible for the overlimiting current. Energy consumption increased when the current density supplied exceeded the limiting current density (LCD) values, because additional energy was necessary to overcome the plateau potential. Beyond the LCD values the energy consumption required to get a certain removal efficiency was not affected by the current density applied. The result suggests that it is allowed to operate electrodialysis processes at as high as possible current density unless water-splitting does not occur.