• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.12
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• pp.1133-1140
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• 2011

Current design process for the Hall effect thruster has relied on expensive experimental method based on the limited historical data. In this study, a proper design space for the Hall effect thruster is chosen and associated design space exploration is conducted based on a recently proposed numerical method in order to improve current design process. According to the results of the design space exploration, performance envelope is determined for the given design space and the correlations between performance metrics are analyzed. Further analysis shows that main factors in performances for the Hall effect thruster are the anode mass flow rate and the discharge voltage.

• Journal of Sensor Science and Technology
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• v.25 no.5
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• pp.310-319
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• 2016

Three types of gap sensors, a capacitive gap sensor, an eddy current gap sensor, and a Hall effect gap sensor are described and evaluated through experiments for the purpose of precise gap sensing for micrometer scale movement, and a novel type of differential hall effect gap sensor is proposed. Each gap sensor is analyzed in terms of resolution and environment dependency including temperature dependency. Furthermore, a transport system for AMOLED deposition is introduced as a typical application of gap sensors, which are recently receiving considerable attention. Based on the analyses, the proposed differential Hall effect gap sensor is found to be the most suitable gap sensor for precise gap sensing, especially for application to a transport system for AMOLED deposition. The sensor shows resolution of $0.63mV/{\mu}m$ for the overall range of the gap from 0 mm to 2.5 mm, temperature dependency of $3{\mu}m/^{\circ}C$ from $20^{\circ}C$ to $30^{\circ}C$, and a monotonic characteristic for the gap between the sensor and the target.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.315-317
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• 2003

This paper deals with the position control of an AC servo motor using linear hall-effect sensors. The price of these is very low, but it is possible to make position control of motor similar to a control using an encoder. This paper introduces the design of motor using linear hall-effect sensors and shows the results of control.

• Korean Journal of Materials Research
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• v.12 no.3
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• pp.195-199
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• 2002

Planar Hall effect of ferromagnetic GaMnAs thin films was investigated for the first time. The films were grown in an optimized growth condition via molecular beam epitaxy at low temperatures. For the optimization of the growth conditions, we used reflection high-energy electron diffraction, electrical conductivity, double crystal x-ray diffraction, and superconducting quantum interference device measurements techniques. We observed that the difference between the longitudinal resistance and the transverse resistance matches the planar Hall resistance. The ratio of the planar Hall resistance at saturation magnetic field to that at zero reached above 500%.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.187-190
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• 1991

The analytical model to investigate the effects of the drift and diffusion carrier transport upon the Hall effect is presented and applied to the general PN junction structure. The diffusion current effect on the Hall coefficient can not be considered in the conventional model, which produces the conversion of the direction of the induced Hall field between measured and calculated values. The proposed analytical model which considers the diffusion current effect provides the coincident results with the previous experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.70-75
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• 2010

The objective of this paper is to propose a new velocity measurement method for an electro-mechanical fin actuator. The model of the electro-mechanical fin actuator includes uncertainties such as unknown disturbances and parameter variations in flight condition. So, an electro-mechanical fin actuator system needs robust control algorithm which requires not only position information but also velocity information. Usually, analog tachometers have been used for velocity feedback in an electro-mechanical fin actuator. However, using these types of sensors have problems such as the cost, space, and malfunction. These problems lead to propose a new velocity measurement method using linear type Hall-effect sensor. In order to verify the proposed method, several experiments are performed using Model Following Sliding Mode Controller(MFSMC). It is shown that the MFSMC with a new velocity measurement method using linear type Hall-effect sensor can satisfy the requirements without using of velocity sensor.

• Journal of Magnetics
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• v.18 no.4
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• pp.454-459
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• 2013

This paper deals with an optimal angle error reduction method of magnetic position sensor using hall effect elements. The angle detection simulation for the magnetic position sensor is performed by 3 dimensional finite element method and Taguchi method, one of the design of experiments. The magnetic position sensor is required to generate ideal sine and cosine waveforms from its hall effect elements according to rotation angle for precise angle information. However, the output signals are easy to include harmonics due to uneven magnetic field distribution from permanent magnet in the air-gap in the vicinity of hall effect elements. For the Taguchi method, three design parameters related to position of hall effect elements and shape of back yoke are selected. The characteristics of optimal magnetic position sensor are compared with those of original one in terms of simulation as well as experiment. Finally, the performances of the motor adopting original model and optimal model are represented for the purpose of verification of motor performance due to signals from magnetic position sensor.

• Bulletin of the Korean Mathematical Society
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• v.55 no.3
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• pp.735-747
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• 2018

This paper deals with the asymptotic behavior of solutions to the generalized MHD and Hall-MHD systems. Firstly, the upper bound for the generalized MHD and Hall-MHD systems is investigated in $L^2$ space. Then, the effect of the Hall term is analyzed. Finally, we optimize the upper bound of decay and obtain their algebraic lower bound for the generalized MHD system by using Fourier splitting method.

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.59-59
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• 2009

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.377-386
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• 2015

DubaiSat-2 is the first satellite developed in Korea equipped with a hall-effect thruster. In this paper, the performance of the DubaiSat-2 hall-effect thruster is verified by analyzing the orbit information of DubaiSat-2. The preparation and performance of orbit operations during 8 months after launch (2013.11.21., UTC) is emphasized and the effects of solar activity on orbit evolution is analyzed. In particular, the hall-effect thruster's thrust is estimated by analyzing difference between observed orbit evolution and predicted orbit. As a result, the estimated thrust is similar to the ground experiment result of 11 mN. The summarized result in this paper would be important reference to improve the stability and effectiveness of satellite operation during the early operation and normal mission lifetime in case of low Earth orbit satellites.