• Journal of the Korean Magnetics Society
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• v.9 no.5
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• pp.227-233
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• 1999

The magnetic field in single-layer solenoid with multi-current is calculated using Elliptical function, Legendre polynomials and Biot-Savart law. The optimization conditions to a highly uniform magnetic field in the center of solenoid has been studied. The variation of magnetic field depending on radius difference was examined. The uniformity of magnetic field is compared with that obtained each multi-current method. The five-current method increases the working space within 0.02 ppm uniformity by eighty times that using single current method. And this method improves the magnetic field uniformity which is equivalent to the effect of 160 m long solenoid by using single current.

• Journal of the Korean institute of surface engineering
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• v.18 no.3
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• pp.105-115
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• 1985

Lead-tin-copper ternary alloy electrodeposition is conducted onto the inner bore surface of plain bearings as an overlay in order to investigate the effect of slot width, current density and fluoboric acid concentration on the uniformity of overlay. The thickness of overlay is analyzed by means of current distribution resulting from the overvoltage of plating bath and the apparent distance between cathode and anode. The result demonstrate that the uniformity of overlay is remarkably dependent of the slot size and current density, but has little bearing on the fluoboric acid concentration over 100g/L. This present study indicates that uniform overlay is obtainable within the tolerable thickness of ${\pm}2{\mu}m$ by using the slot width of 22mm. The surface morphology examination also shows the important role of concentration polarization of the micro-uniformity of overlay. The micro-uniformity has improved at the low concentration polarization which resulted from operating at the low current density and high fluoboric acid concentration. The surface morphology of deposits exhibits the vivid pyramid crystalline in the plating condition of low concentration polarizatio and all deposits have columnar structure parallel to the applied electric field regardless of the electroplating condition used.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1436-1439
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• 2005

A novel current-type data driver for active matrix organic light emitting diode (AMOLED) is proposed for current uniformity enhancement among its output channels. New architecture is composed of shadow DACs that precharge output stages, a single-real DAC that correct the output level to a real target current level and output stages that operate in 3 states of sampling, correcting and driving. Simulation results show that the proposed driving method and circuits improve the current uniformity among output channels of a current-type driver IC.

• Journal of the Korean Electrochemical Society
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• v.12 no.4
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• pp.317-323
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• 2009

Theoretical calculations for the secondary current distributions for the electrode with a projection part in electroplating were performed. Two kinds of electrodes were considered. One is a electrode with the overall conducting surfaces(Case 1) and the other is an electrode in which only a projection part has a conducting surface(Case 2). The effects of applied potential, the ratio of ion exchange current to conductivity, $\xi$ and the aspect ratio on the current distribution were examined. The increase of applied current or the value of $\xi$ decreased the uniformity of current distribution. The small value of aspect ratio resulted the more uniform current distribution and Case 2 showed the better uniformity than Case 2. When this model was applied into an electrode with various projection parts, the local current distribution along the electrode surface were obtained successfully. In this case, the decrease of $\xi$ also increase the uniformity of current distribution as seen previously.

• Progress in Superconductivity and Cryogenics
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• v.9 no.3
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• pp.41-45
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• 2007

This paper presents transport current non-uniformity in a joint for superconducting multistage cable-in-conduit conductor (CICC) and relaxation in the CICC. The joint is considered to have a current loop linked to an external magnetic field so that it becomes an emf voltage source. It is numerically analyzed using an electrical transmission line model. The inductive current in a resistive joint is compared to that of a non-resistive joint when the ramping field is applied vertically to the joints. Regarding the parameter values of the model. a full scale $Nb_3Sn$ CICC and a strand-to-strand (STS) joint for the toroidal field magnet of the KSTAR (Korea Superconducting Tokamak Advanced Research) device are referenced to. It is found that the resistive joint prevents the current from rising too much and enhances decaying the current when the ramping stops. The 'flattop' current is found to be proportional to the ramp rate of the field (dB/dt). The relaxation length, which is defined as the length within which the maximum induced current falls by 1/e. is found to saturate within 0.27m.

• Korean Journal of Materials Research
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• v.14 no.3
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• pp.196-202
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• 2004

A numerical simulation based on the finite element method is used to investigate the effect of a reciprocal paddle on the uniformity of deposition rates at a patterned electrode. The calculated deposition rates agreed well with the measured values. The influences of the paddle velocity, the gap between cathodes and paddles, anode size and the distance between the anode and cathode have been studied. The optimum conditions on the paddle and geometric factors for electrodeposit uniformity could be obtained.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.285-286
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• 2007

Current distributions according to electrode patterns in vertical structured InGaN/GaN LED (light emitting diode) were investigated quantitatively by utilizing three dimensional electrical circuit modeling method. The uniformity of the injected current density in the active layer was compared among different electrode patterns. It was found that the current uniformity was greatly dependent on the electrode pattern in vertical InGaN/GaN LEDs.

• Journal of Information Display
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• v.3 no.3
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• pp.35-43
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• 2002

Silicon-based 0.69-inch AMOEL microdisplay with integrated driver and timing controller circuits for microdisplay applications has been developed using 0.35 ${\mu}m$ l-poly 4-metal standard CMOS process with 5 V CMOS devices and CMP (Chemical Mechanical Polishing) technology. To reduce the large data programming time consumed in a conventional current programming pixel circuit technique and to achieve uniform display, de-amplifying current mirror pixel circuit and the current-mode data driver circuit with threshold roltage compensation are proposed. The proposed current-mode data driver circuit is inherently immune to the ground-bouncing effect. The Monte-Carlo simulation results show that the proposed current-mode data driver circuit has channel-to-channel non-uniformity of less than ${\pm}$0.6 LSB under ${\pm}$70 mV threshold voltage variaions for both NMOS and PMOS transistors, which gives very good display uniformity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.753-758
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• 2011

Magnetic field and Electric field of High Temperature Superconducting magnet are very important to analysis of superconducting magnet. The maximum perpendicular magnetic field was applied to the outermost pancake windings. The critical current of all the magnet windings is limited by the critical current of the outermost pancake windings. The E-J relation was used to determine the critical current, and an evolution s trategy was adopted for the optimization of gap length between each pancake windins. The results of calculations show that the critical current and the central magnetic field and uniformity increased by 82.6% and 31.6% and 50.8%, respectively, for a magnet consisting of ten pancake windings. This paper did an analysis the cause of increase the critical current and central magnetic field and uniformity in no gap and optimal gap model.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.100-102
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• 2005

This paper presents evaluation of the electrical uniformity of zinc oxide varistors for lightning arresters. Two types of varistors were prepared which are a domestic varistor destroyed in the long duration current impulse withstand test and a new imported varistor. The domestic varistor exhibited good electrical uniformity except destroyed parts, but the imported varistor showed the worse results.