• Title, Summary, Keyword: Current density

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Synthesis and Magnetic Properties of Electrodeposited Cobalt-Iron-Vanadium Thin Films

  • Chae, Kwang-Pyo
    • Journal of Magnetics
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    • v.11 no.2
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    • pp.87-89
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    • 2006
  • CoFeV thin film alloys were fabricated by electrodeposition, and the dependences of their magnetic properties on the current density were investigated using an X-ray diffractometer and a vibrating sample magnetometer. The deposited Co increased from about 45 to 60 wt.% with increasing current density until $25mA/cm^2$ whereas the deposited Fe decreased from about 55 to 40 wt.% with increasing current density until $25mA/cm^2$. The deposited V, about 2 wt.%, was independent of the current density. The current efficiencies of electrodeposition decreased linearly from about 40 to 29% with increasing current density. The X-ray diffraction measurement showed that all peaks of the CoFeV films were consistent with those of a typical Co hcp and Fe bcc mixed phase. An increase in the current density decreased the grain size and increased the lattice constant. The saturation magnetization increased from about 2.2 to 2.5 T with increasing current density. The coercivity measured in the perpendicular direction decreased from 260 to 120 Oe with increasing current density; a drastic drop of 60 Oe occurred at $5mA/cm^2$. The coercivity measured in the in-plane direction remained almost unchanged, at about 20 Oe, with increasing current density.

Property and Surface Morphology of Copper Foil on the Current Density (구리 박막의 표면형상과 물성에 대한 전류밀도 영향)

  • Woo, Tae-Gyu;Park, Il-Song;Jung, Kwang-Hee;Seol, Kyeong-Won
    • Korean Journal of Materials Research
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    • v.20 no.10
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    • pp.555-558
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    • 2010
  • This study examined the effect of current density on the surface morphology and physical properties of copper plated on a polyimide (PI) film. The morphology, crystal structure, and electric characteristics of the electrodeposited copper foil were examined by scanning electron microscopy, X-ray diffraction, and a four-point probe, respectively. The surface roughness, crystal growth orientation and resistivity was controlled using current density. Large particles were observed on the surface of the copper layer electroplated onto a current density of 25 mA/$cm^2$. However, a uniform surface and lower resistivity were obtained with a current density of 10 mA/$cm^2$. One of the important properties of FCCL is the flexibility of the copper foil. High flexibility of FCCL was obtained at a low current density rather than a high current density. Moreover, a reasonable current density is 20 mA/$cm^2$ considering the productivity and mechanical properties of copper foil.

Magnetic Resonance Imaging of a Current Density Component

  • Oh, Suk-Hoon;Park, Tae-Seok;Han, Jae-Yong;Lee, Soo-Yeol
    • Journal of Biomedical Engineering Research
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    • v.25 no.3
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    • pp.183-188
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    • 2004
  • Magnetic resonance current density imaging (MRCDI) is a useful method for measuring electrical current density distribution inside an object. To avoid object rotations during the conventional MRCDI scans, we have reconstructed current density component images by applying a spatial filter to the magnetic field data measured both inside and outside the object. To measure the magnetic field outside the object with MRI, we immersed the object in a water tank. To evaluate accuracy of the current density imaging, we have made a conductivity phantom with a corresponding finite element method model. We have compared the experimentally obtained current density images with the ones calculated by the finite element method. The average errors of the reconstructed current density images were 6.6 ∼ 45.4 % when the injected currents were 1 ∼ 24 mA. We expect that the current density component imaging technique can be used in diverse biomedical applications such as electrical therapy system developments and biological electrical safety analysis.

Estimate of Current Density Distribution in Electroforming Process Using Finite Element Analysis (유한요소해석을 이용한 전주공정에서의 전류밀도 분포 예측)

  • 강대철;김헌영;전병희
    • Transactions of Materials Processing
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    • v.13 no.3
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    • pp.279-284
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    • 2004
  • Electroforming is the highly specialized use of electrodeposition for the manufacture of metal parts and basically a specialized form of electroplating. So, we can apply electrochemical system analysis for electroforming process. Electrochemical systems are concerned with the interplay between electricity and chemistry, namely the measurements of electrical quantities, such as current density, potential, and charge, and their relationship to chemical parameters. This paper based on the basic equations of electrics and electrochemical kinetics, was employed for a theoretical explanation of the current density distribution on electroforming process. We calculated current density distribution and potential distribution on cathode. Also, calculated current density distribution of vertical direction. It was shown that current density is related with distance of between anode and cathode and mass transfer process.

Development of a predictive model of the limiting current density of an electrodialysis process using response surface methodology

  • Ali, Mourad Ben Sik;Hamrouni, Bechir
    • Membrane Water Treatment
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    • v.7 no.2
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    • pp.127-141
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    • 2016
  • Electrodialysis (ED) is known to be a useful membrane process for desalination, concentration, separation, and purification in many fields. In this process, it is desirable to work at high current density in order to achieve fast desalination with the lowest possible effective membrane area. In practice, however, operating currents are restricted by the occurrence of concentration polarization phenomena. Many studies showed the occurrence of a limiting current density (LCD). The limiting current density in the electrodialysis process is an important parameter which determines the electrical resistance and the current utilization. Therefore, its reliable determination is required for designing an efficient electrodialysis plant. The purpose of this study is the development of a predictive model of the limiting current density in an electrodialysis process using response surface methodology (RSM). A two-factor central composite design (CCD) of RSM was used to analyze the effect of operation conditions (the initial salt concentration (C) and the linear flow velocity of solution to be treated (u)) on the limiting current density and to establish a regression model. All experiments were carried out on synthetic brackish water solutions using a laboratory scale electrodialysis cell. The limiting current density for each experiment was determined using the Cowan-Brown method. A suitable regression model for predicting LCD within the ranges of variables used was developed based on experimental results. The proposed mathematical quadratic model was simple. Its quality was evaluated by regression analysis and by the Analysis Of Variance, popularly known as the ANOVA.

The Effect of Surface Recombination Current on the Saturation Current in Si Solar Cell (Si 태양전지(太陽電池)의 표면재결합(表面再結合) 전류(電流)가 포화전류(飽和電流)에 미치는 영향(影響))

  • Shin, Kee-Shik;Lee, Ki-Seon;Choi, Byung-Ho
    • Solar Energy
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    • v.8 no.2
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    • pp.12-18
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    • 1988
  • The effect of surface recombination current density on the saturation current density in Si solar cell has been studied. Theoretical model for surface recombination current was set up from emitter transparent model of M.A. Shibib, and saturation current of Si solar cell made by ion implantation method was also measured by digital electrometer. The theoretical surface recombination current density which is the same as saturation surface recombination current density in Shibib model was $10^{-11}[A/cm^2]$ and the measured value was ranged from $8{\times}10^{-10}$ to $2{\times}10^{-9}[A/cm^2]$. Comparing with the ideal p-n junction of Shockley, transparent emitter model shows improved result by $10^2$ order of saturation current density. But there still exists $10^2$ order of difference of saturation current density between theoretical and actual values, which are assumed to be caused by 1) leakage current through solar cell edge, 2) recombination of carriers in the depletion layer, 3) the series resistance effect and 4) the tunneling of carriers between states in the band gap.

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The Effect of Additives on the Current Efficiency and the Microstructure of Trivalent Cr Electrodeposits Plated in Flow Cell System (고속도금된 3가 크롬도금의 전류효율 및 조직특성에 미치는 첨가제의 영향)

  • 예길촌;서경훈
    • Journal of the Korean institute of surface engineering
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    • v.37 no.2
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    • pp.92-98
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    • 2004
  • The current efficiency and the microstructure of the trivalent Cr deposits plated in flow cell system were investigated according to additives in sulfate bath and current density. The current efficiency of the deposits plated in the formic acid complexed bath was noticeably higher than that of the deposits from glycine complexed bath. The current efficiency of the deposits from the complexed baths with boric acid buffer increased linearly with current density in the range of 60-100 A/dm$^2$, while that of the deposits from the baths with both Al sulfate and mixed buffers increased parabolically with current density. The nodular crystallite size of the deposits increased with current density, and the deposits plated in low current density region had relatively smooth surface appearance with fine grains. The structure of the deposits from the complexed baths with boric acid buffer changed from amorphous structure to crystalline one with strong (110)peak with increasing current density. The deposits from the baths with both Al sulfate and mixed buffers had generally amorphous structure.

Influence of Applied Current Density on Properties of Cu thin layer Electrodeposited from Copper Pyrophosphate Bath (피로인산동 도금용액으로부터 전기도금 된 Cu 도금층의 물성에 미치는 인가전류밀도의 영향)

  • Yoon, Pilgeun;Park, Deok-Yong
    • Journal of the Korean institute of surface engineering
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    • v.53 no.4
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    • pp.190-199
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    • 2020
  • Copper pyrophosphate baths were employed in order to study the dependencies of current efficiency, residual stress, surface morphology and microstructure of electrodeposited Cu thin layers on applied current density. The current efficiency was obtained to be more than about 90 %, independent of the applied current density. Residual stress of Cu electrodeposits was measured to be in the range of -30 MPa and 25 MPa with the increase of applied current density from 0.5 to 15 mA/㎠. Relatively smooth surface morphologies of the electodeposited Cu layers were obtained at an intermediate current range between 3 and 4 mA/㎠. The Cu electrodeposits showed FCC(111), FCC(200), and FCC(220) peaks and any preferred orientation was not observed in this study. The average crystalline size of Cu thin layers was measured to be in the range of 44~69 nm.

Effects of baffles through the parallel flow channel in a PEM fuel cell (PEM 연료전지 평행류 채널에서 Baffle의 영향)

  • Oh, Chang-Mook;Lee, Kyu-Jung
    • Proceedings of the SAREK Conference
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    • pp.9-14
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    • 2008
  • The effects of baffles in PEM fuel cell with parallel flow channel has been simulated by using conmmercial program. The simulation has been conducted through the channel and there are four different heights of baffles, No Baffle($H_b$=0), Partially Blocked Baffle(0.25, 0.5, 0.75), Fully Blocked Baffle(1) conditions. The result shows that current density changes while placing a baffle at the various positions along the channel. Current density with a single baffle is higher than that without baffle and current density using Fully Blocked Baffle(FBB) is much higher than current density using Partially Blocked Baffle(PBB). When the baffle is closer to outlet of the channel, current density increases. It is found that pressure is related to current density. If the pressure is higher, the better performance will be expected.

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Current Density and Thickness Effects on Magnetic Properties of Electrodeposited CoPt Magnetic Films

  • Kim, Hyeon Soo;Jeong, Soon Young;Suh, Su Jeong
    • Journal of Magnetics
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    • v.18 no.4
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    • pp.417-421
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    • 2013
  • The dominant magnetization reversal behavior of electrodeposited CoPt samples with various thicknesses deposited at different current densities was the domain wall motion by means of wall pinning. The magnetic interaction mechanism was dipolar interaction for all samples. The dipolar interaction strength was significantly affected by the sample thickness rather than by the current density, while the magnetic properties were closely related to the current density.