• Title/Summary/Keyword: Carrier free

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Studies on Carrier-Free Yttrium-90 with Membrane Filters (막여과지에 의한 무단체 이트륨-90에 관한 연구)

  • Jae, Won-Mok
    • Journal of the Korean Chemical Society
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    • v.14 no.4
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    • pp.347-355
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    • 1970
  • The state of carrier-free yttrium-90 has been studied by filtration method with membrane filters. The studies include the adsorption ratio of carrier-free yttrium-90 on membrane filters by the change of PH, concentration of yttrium-90, and the pore size of member filters. The adsorption followed to Freundlich adsorption isotherm. The adsorption mechanism was proposed by the adsorption of transient state as an ionic form of $Y^{3+}$, and the experimental results were explained satisfactorily by the proposal. The adsorbed state of yttrium was present in the forms of yttrium such as $Y^{3+},\;Y(OH)^{3+},\;Y(OH)^{2+},\;Y(OH)^+_3,\;and\;Y(OH)_3$,and the existing ratios of the forms of yttrium were sharply changed by PH. It seems to be valid tha the carrier-free yttrium-90 exists mostly in $Y^{3+}$ state.

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Magnetically levitated transport system for a controller-free carrier (제어기 무장착 운송대를 위한 선형운동 자기부상 운송시스템)

  • Son, Yeong-Uk;Park, Gi-Hwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.12
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    • pp.2196-2208
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    • 1997
  • In this work, a magnetic levitation (maglev) system is developed to transport a wafer between semiconductor fabrication process modules in clean rooms to take advantages of eliminating particle and oil contamination that normally exist in conventional transport systems due to contact motion of mechanical components. A main feature of the maglev system developed in this work is that a controller and power supplying part are not mounted on the moving carrier but on the stationary track, which is defined a controller-free carrier, to reduce carrier's weight. Iron-core electromagnets and irons are used for levitation, and air-core electromagnets and permanent magnets are used for stabilization. Analysis, design, and modeling of the magnetically levitated transport system are presented. The performance of the maglev system is experimentally demonstrated.

MAGNETOTRANSPORT OF SEMIMETALLIC Bi THIN FILMS CROWN BY ELECTROPLATING AND SPUTTERING

  • M. H. Jeon;Lee, K. I.;Lee, K. H.;J. Y. Chang;K. H. Shin;S. H. Han;Lee, W. Y.;J. G. Ha
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.150-151
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    • 2002
  • In recent years, semi-metallic Bismuth (Bi) has attracted significant attention due to very large magnetoresistance (MR) at room temperature originating from long carrier mean free path l and small effective carrier mass m*[1, 2]. In particular, the MR behavior and long carrier mean free path l in Bi thin films can be exploited for spintronic devices, e.g. magnetic field sensors and spin-valve transistors. In present work, we present the magnetotransport properties of the electroplated and sputtered Bi thin films in the temperature range 4-300 K. (omitted)

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Numerical Simulation Study on Gas-Particle Two-Phase Jets in a Crossflow (I) -Two-Phase Jet Trajectory and Momentum Transfer Mechanism- (고체입자가 부상된 자유 횡분류 유동에 대한 전산모사 연구 (I) -2상 분류궤적과 운동량 전달기구-)

  • 한기수;정명균
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.1
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    • pp.252-261
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    • 1991
  • A particle trajectory model to simulate two-phase particle-laden crossjets into two-dimensional horizontal free stream has been developed to study the variations of the jet trajectories and velocity variations of the gaseous and the particulate phases. The following conclusions may be drawn from the predicted results, which are in agreement with experimental observations. The penetration of the two-phase jet in a crossflow is greater than that of the single-phase jet. The penetration of particles into the free stream increases with increasing particle size, solids-gas loading ratio and carrier gas to free stream velocity ratio at the jet exit. When the particle size is large, the solid particles separate from the carrier gas , while the particles are completely suspended in the carrier gas for the case of small size particles. As the particle to carrier gas velocity ratio at the jet exit is less than unity, the particles in the vicinity of the jet exit are accelerated by the carrier gas. As the injection angle is increased, the difference of the particle trajectory from that of the pure gas becomes larger. Therefore, it can be concluded that the velocities and trajectories of the particle-laden jets in a crossflow change depending on the solids-gas loading ratio, particle size, carrier gas to free stream velocity ratio and particle to gas velocity ratio at the jet exit.

Modeling of free carrier absorption coefficients in anisotropic semiconductor quantum well structures (비등방성 반도체 양자우물에서의 자유전자 흡수에 의한 광자의 흡수계수의 모델링)

  • 김경염
    • Korean Journal of Optics and Photonics
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    • v.10 no.1
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    • pp.80-86
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    • 1999
  • The theoretical modeling of free carrier absorption in quantum wells grown on anisotropic materials is presented for the first time. The intersubband and intrasubband free carrier absorption are distinguished and the contribution of each subband to them is calculated separately. The calculated results are compared with the experimental values of $\delta$-doped Si quantum wells in literature.

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The Production of Carrier Free Indium-111 with MC-50 Cyclotron (MC-50 싸이클로트론을 이용한 In-111 제법 개발)

  • Chun, K.S.;Suh, Y.S.;Yang, S.D.;Chai, J.S.;Jee, K.S.;Lee, J.D.
    • Journal of radiological science and technology
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    • v.13 no.2
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    • pp.43-49
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    • 1990
  • [ $^{111}$ ]In has wide applications in nuclear medicine for labelling and in-vivo distribution studies. A method is developed for the production of carrier free $^{111}$In using the reaction $^{nat.}Cd(p,\;xn)$ $^{111}$In with MC-50 cyclotron. Carrier free $^{111}$In was separated from the irradiated metallic cadmium by liquid-liquid extraction and cation exchange chromatography. The yield of $^{111}$In at EOB is $0.8mCi/{mu}\;Ahr$ and the nuclidic purity is over 99%. $^{111}In-DTPA\;and\;^{111}In-bleomycin$ were prepared for medical study.

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Carrier Densities of CdSe Thin Films (CdSe 박막반도체의 반송자 밀도)

  • 김기원
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.21 no.5
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    • pp.7-10
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    • 1984
  • Generally, free carrier densities of single crystal semiconductors are indifferent to methods of measurement. Free carrier densities of CdSe thin films, however, were measured invarious values with different methods In this paper, C-V method, Seebeck effect and a.c. Hall effect were used to measure carries densities of CdSe thin films. Carrier densities of CdSe thin films were in the range of 10 - 10 carriers/㎤. And causes of different results were discussed.

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The Mitochondrial Tricarboxylate Carrier of Silver Eel: Chemical Modification by Sulfhydryl Reagents

  • Capobianco, Loredana;Impagnatiello, Tecla;Ferramosca, Alessandra;Zara, Vincenzo
    • BMB Reports
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    • v.37 no.5
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    • pp.515-521
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    • 2004
  • The tricarboxylate (or citrate) carrier was purified from eel liver mitochondria and functionally reconstituted into liposomes. Incubation of the proteoliposomes with various sulfhydryl reagents led to inhibition of the reconstituted citrate transport activity. Preincubation of the proteoliposomes with reversible SH reagents, such as mercurials and methanethiosulfonates, protected the eel liver tricarboxylate carrier against inactivation by the irreversible reagent N-(1-pyrenyl)maleimide (PM). Citrate and L-malate, two substrates of the tricarboxylate carrier, protected the protein against inactivation by sulfhydryl reagents and decreased the fluorescent PM bound to the purified protein. These results suggest that the eel liver tricarboxylate carrier requires a single population of free cysteine(s) in order to manifest catalytic activity. The reactive cysteine(s) is most probably located at or near the substrate binding site of the carrier protein.